So when I was looking through the scrap dumpster, I found a boardset with a big LCD on it and two wires sticking out the back. Didn't have a clue what it was, but reverse-engineered (not really) the board to find that the two wires were, hard to believe, hot and neutral for AC feed. Strange. Never seen anything that low-consumption take such a high input.
There's reason to the rhyme, though. Without isolation from the AC line, you can inject an RF signal back into the waveform.
I figured I'd bite the bullet and plug it in. I tested the connection to find that there was no short to speak of and the resistance was actually around 8 megaohms, telling me that there's a multi-stage powerup process. With a standard figure-8 cord as my socket, I put some distance between myself and the board and plugged it.
Nothing.
That is, until the display lit up and showed "Initializing..."
Once started, it showed eight choices, one for each button. I clicked the button below Info and got the details on what the device was. It turns out I had in my possession the internals for a home command center that normally goes for about $300. Only this one has some defect I don't know about yet.
Regardless, it has a 240x120 pixel LCD display with a nice white backlight.
Saturday, October 27, 2007
Friday, October 26, 2007
Let There Be Light: Reloaded
I hit the dumpster again and pulled out (after much digging and transferring) about fifty Sharp brand 3.6" QVGA TFT LCDs with touchscreens attached. I looked up the info through Google and found they use LEDs for the backlight. Seven white ones, specifically. Tearing a broken one open, I found The LEDs are on a tape about 1/8" wide and wired in series. The spec sheet says they are meant to be driven with about 28VDC. That's not easy to get out of a DC to DC converter. Most don't do that kind of step-up.
What isn't difficult is the task of getting the proper brightness out of the assembly. I used a 12VDC adapter to drive four LEDs initially and found they were decently bright. Hard to look at, at least. Then I remembered the spec of 28VDC and realized I was supposed to be driving three with the adapter I had. Well, I did that and saw dots for about six hours. Each one, spaced the way they are, is more powerful than the same length of a standard CCFL. Giggity.
The small modules mounted to the wider circuit boards are decent, but may be too big without dremel work. The upside to those units is the fact that they are wired in parallel, allowing for easier integration with the 5VDC drive the inverter normally uses. I have a switching converter that will drop 5VDC to the 4VDC I need.
What isn't difficult is the task of getting the proper brightness out of the assembly. I used a 12VDC adapter to drive four LEDs initially and found they were decently bright. Hard to look at, at least. Then I remembered the spec of 28VDC and realized I was supposed to be driving three with the adapter I had. Well, I did that and saw dots for about six hours. Each one, spaced the way they are, is more powerful than the same length of a standard CCFL. Giggity.
The small modules mounted to the wider circuit boards are decent, but may be too big without dremel work. The upside to those units is the fact that they are wired in parallel, allowing for easier integration with the 5VDC drive the inverter normally uses. I have a switching converter that will drop 5VDC to the 4VDC I need.
Tuesday, October 23, 2007
Let There Be Light
One of my earlier project ideas is now becoming very possible. I recall writing about my wish to design an LED backlight for one of my older laptop computers. The idea is the same, but the platform has changed. I will be targeting one of my Toshiba Portege 3490CT units for the upgrade.
The backlights I have are salvaged from LCD displays I recovered from the scrap box at the plant where I work. Since LCDs are basically worthless for recycling, rescuing them like this was a no-brainer.
I've measured the widths of the LCD panel and the backlight boards to find that five boards will fit if I trim the far edge of the backlight board to eliminate blank space. Also, the slim nature of the LEDs allows for the boards to be stacked with the LED sides placed together. With three LEDs on each board, this adds up to fifteen or thirty LEDs lighting up the panel. What I don't know is how bright each LED is. If I knew that, I could figure out what duty cycle I will need to drive the light bar with to get the same brightness as the original CCFL backlight.
After this operation, I will need to figure out the logic of the inverter control signals so I can design drive circuitry for the array.
The backlights I have are salvaged from LCD displays I recovered from the scrap box at the plant where I work. Since LCDs are basically worthless for recycling, rescuing them like this was a no-brainer.
I've measured the widths of the LCD panel and the backlight boards to find that five boards will fit if I trim the far edge of the backlight board to eliminate blank space. Also, the slim nature of the LEDs allows for the boards to be stacked with the LED sides placed together. With three LEDs on each board, this adds up to fifteen or thirty LEDs lighting up the panel. What I don't know is how bright each LED is. If I knew that, I could figure out what duty cycle I will need to drive the light bar with to get the same brightness as the original CCFL backlight.
After this operation, I will need to figure out the logic of the inverter control signals so I can design drive circuitry for the array.
Friday, October 12, 2007
Just chill!
My wife and I bought a mini-fridge from Target a little over two years ago and have used it for sodas ever since. While I never did measure the actual temperature of the machine, I knew when it wasn't chilling as well as it had been. This week, I opened it up to get a look at things and see about changing the heatsink grease out.
The backstory to this is I took it apart soon after buying it to figure out how well-built it was as I've long known anything Made In China tends to be slapped together at high speed in mass quantities. I was right. The heat transfer grease used was the standard white silicone goo with zinc oxide particles in it. Not very good, really. I replaced it with some cheap copper grease which was better than the stock compound. It stayed like this for two years.
I had used the copper compound on a few computer systems and noticed that it tended to separate after a few months, screwing up the coverage. I figured I'd take care of it when I had something better.
What I ended up with was a kit from Arctic Silver that had their two cleaning fluids and ceramic-based compound. A compound rated for high-output CPU dies should be able to take on the range of temperatures from the cold and hot side of the Peltier device used as the cooler in the fridge.
The added bonus in all of that was that the compound was being put on six surfaces, making three layers of the stuff, with the central aluminum cold block being the major addition to the design.
So, on with the process.
I undid the screws on the back to access the assembly and saw there was dust on the housing that the filter screens missed. I knew it was time for a cleaning anyway. No surprise there.
What I didn't expect was what I found when I removed the chiller assembly. The cooling fins were completely caked with dirt at the inflow on one side, explaining why the unit wasn't working as well as it did when new. Since Peltier devices don't wear out and the fans were fine, it had to be something like that.
A vacuuming later, the fins, fans and casing were clean as new, or at least close to it. It was time to tear into the cooler. The assembly is better than most of the plug-in travel coolers I've cannibalized for their Peltier modules. Those usually have a Peltier module sandwiched between a heatsink and coldsink and leave it at that. The only one I didn't see with this assembly style was a cheap one I picked up for a couple of dollars once. It had a cold-block with a thermostat for the heating function bolted to it.
The gigantic heatsink of about ten inches square and three inches thick has the Peltier module resting against it. This is where the high-grade compound really shines. That's what it's made for. The Peltier has the cold-block touching the cold-side (naturally) and the other side of this block is pressed against the back of the coldsink (their term, not mine). Ther entire assembly is bolted together with styrofoam insulation surrounding the primarily cold areas and silicone caulk sealing it all up.
When I replaced the factory silicone heatsink grease with the copper compound, I broke the seal and never replaced it. Luckily, I had a few syringes of RTV sealant salvaged from the trash at work to use for that.
I used the Arcticlean products and paper towels to remove as much copper as I could from the surface to which the Ceramique compound was to be applied. I figured any that stayed around was lodged in pits in the surface and likely wouldn't budge. Applying the new compound with the edge of an old driver's license was straightforward. Some use credit cards for this part, but both work equally well. I had to use a lot more compound than what is required for a computer CPU, but that's to be expected for the surfaces I was joining.
I pressed the greased Peltier module to the freshly greased heatsink and held the Peltier in place while covering the cold side with the new compound. That done, I put down a layer of RTV sealant over the foam contact area of the heatsink, inserted the bottom-greased cold-block into the insulator and fit it to the top of the Peltier device. The plastic frame that held the insulator in place from the coldsink side needed sealing as this was where the factory seal had been placed. I ran a bead of RTV around the top of the insulator where the frame contacted and on the top of the frame where the coldsink contacted. Then, just to be sure, I ran a bead on the ouside of the frame, joining it to the coldsink. To finish it all off, I bolted the entire assembly back together and replaced the silicone caulking in the screw holes with RTV.
I buttoned it all back up and started the fridge. The temperature dropped faster than I've ever seen and the air coming off the heatsink was actually hot. I had done it. The temp stabilized at 41.2F and would not go any lower over the next two days. I noticed that the fans weren't turning as fast and figured it was the thermostat limiting me. Yep.
I looked at the circuit board for the fridge and saw that it had no controls for the thermostat. I figured the thermostat might have controls inside it, however. Yep. It had a resistor network and an 8.2K resistor in series with it all. I shorted the 8.2K and found that the resistive output of the network was 17.49K at the highest and 9.9K at the lowest versus 23K at the highest and 16.48K at the lowest before the mod. Since the top reading was just barely getting into the refrigeration range, I left it at that, figuring the bottom rating of 9.9K would never have reason to be used.
I set the fridge to work cooling down. It got to 40.9 and slowed down the cooling trend a bit. It went to 39.2 over one hour's time and is now sitting at 38.3F, two hours after that. I will check the temperature in the morning and give updates as this goes on. I plan to make the fridge chill down as far as possible for the conditions and then add a resistor to keep it that way when close to the maximum setting. I'm sure there comes a point where the temperature won't get any lower with the Peltier module powered continuously. I'll have to find where it will pulse with the best efficiency to allow a lower temperature if that's the case.
Still, I met my goal of getting the temp down into the 30s. Anything extra from here is a bonus. I'd like 35F as an ideal temp and I'm very close. I'll have to stock the fridge with gamer fuel and cold ones since the ones shall be colder than ever before.
For the record, I used a cheap bimetallic thermometer in the past to check the temperature and was able to get down to 45F. The digital wireless thermometer I used for the readings posted in this blog are pretty close, measuring within a degree of the cheap thermometer, the cheap one reading low.
The sending unit was placed on the wire shelf in the fridge so I have no benefit of cold air tending to sink. I will get a bottom reading soon as that is where the beverages will be stored.
The backstory to this is I took it apart soon after buying it to figure out how well-built it was as I've long known anything Made In China tends to be slapped together at high speed in mass quantities. I was right. The heat transfer grease used was the standard white silicone goo with zinc oxide particles in it. Not very good, really. I replaced it with some cheap copper grease which was better than the stock compound. It stayed like this for two years.
I had used the copper compound on a few computer systems and noticed that it tended to separate after a few months, screwing up the coverage. I figured I'd take care of it when I had something better.
What I ended up with was a kit from Arctic Silver that had their two cleaning fluids and ceramic-based compound. A compound rated for high-output CPU dies should be able to take on the range of temperatures from the cold and hot side of the Peltier device used as the cooler in the fridge.
The added bonus in all of that was that the compound was being put on six surfaces, making three layers of the stuff, with the central aluminum cold block being the major addition to the design.
So, on with the process.
I undid the screws on the back to access the assembly and saw there was dust on the housing that the filter screens missed. I knew it was time for a cleaning anyway. No surprise there.
What I didn't expect was what I found when I removed the chiller assembly. The cooling fins were completely caked with dirt at the inflow on one side, explaining why the unit wasn't working as well as it did when new. Since Peltier devices don't wear out and the fans were fine, it had to be something like that.
A vacuuming later, the fins, fans and casing were clean as new, or at least close to it. It was time to tear into the cooler. The assembly is better than most of the plug-in travel coolers I've cannibalized for their Peltier modules. Those usually have a Peltier module sandwiched between a heatsink and coldsink and leave it at that. The only one I didn't see with this assembly style was a cheap one I picked up for a couple of dollars once. It had a cold-block with a thermostat for the heating function bolted to it.
The gigantic heatsink of about ten inches square and three inches thick has the Peltier module resting against it. This is where the high-grade compound really shines. That's what it's made for. The Peltier has the cold-block touching the cold-side (naturally) and the other side of this block is pressed against the back of the coldsink (their term, not mine). Ther entire assembly is bolted together with styrofoam insulation surrounding the primarily cold areas and silicone caulk sealing it all up.
When I replaced the factory silicone heatsink grease with the copper compound, I broke the seal and never replaced it. Luckily, I had a few syringes of RTV sealant salvaged from the trash at work to use for that.
I used the Arcticlean products and paper towels to remove as much copper as I could from the surface to which the Ceramique compound was to be applied. I figured any that stayed around was lodged in pits in the surface and likely wouldn't budge. Applying the new compound with the edge of an old driver's license was straightforward. Some use credit cards for this part, but both work equally well. I had to use a lot more compound than what is required for a computer CPU, but that's to be expected for the surfaces I was joining.
I pressed the greased Peltier module to the freshly greased heatsink and held the Peltier in place while covering the cold side with the new compound. That done, I put down a layer of RTV sealant over the foam contact area of the heatsink, inserted the bottom-greased cold-block into the insulator and fit it to the top of the Peltier device. The plastic frame that held the insulator in place from the coldsink side needed sealing as this was where the factory seal had been placed. I ran a bead of RTV around the top of the insulator where the frame contacted and on the top of the frame where the coldsink contacted. Then, just to be sure, I ran a bead on the ouside of the frame, joining it to the coldsink. To finish it all off, I bolted the entire assembly back together and replaced the silicone caulking in the screw holes with RTV.
I buttoned it all back up and started the fridge. The temperature dropped faster than I've ever seen and the air coming off the heatsink was actually hot. I had done it. The temp stabilized at 41.2F and would not go any lower over the next two days. I noticed that the fans weren't turning as fast and figured it was the thermostat limiting me. Yep.
I looked at the circuit board for the fridge and saw that it had no controls for the thermostat. I figured the thermostat might have controls inside it, however. Yep. It had a resistor network and an 8.2K resistor in series with it all. I shorted the 8.2K and found that the resistive output of the network was 17.49K at the highest and 9.9K at the lowest versus 23K at the highest and 16.48K at the lowest before the mod. Since the top reading was just barely getting into the refrigeration range, I left it at that, figuring the bottom rating of 9.9K would never have reason to be used.
I set the fridge to work cooling down. It got to 40.9 and slowed down the cooling trend a bit. It went to 39.2 over one hour's time and is now sitting at 38.3F, two hours after that. I will check the temperature in the morning and give updates as this goes on. I plan to make the fridge chill down as far as possible for the conditions and then add a resistor to keep it that way when close to the maximum setting. I'm sure there comes a point where the temperature won't get any lower with the Peltier module powered continuously. I'll have to find where it will pulse with the best efficiency to allow a lower temperature if that's the case.
Still, I met my goal of getting the temp down into the 30s. Anything extra from here is a bonus. I'd like 35F as an ideal temp and I'm very close. I'll have to stock the fridge with gamer fuel and cold ones since the ones shall be colder than ever before.
For the record, I used a cheap bimetallic thermometer in the past to check the temperature and was able to get down to 45F. The digital wireless thermometer I used for the readings posted in this blog are pretty close, measuring within a degree of the cheap thermometer, the cheap one reading low.
The sending unit was placed on the wire shelf in the fridge so I have no benefit of cold air tending to sink. I will get a bottom reading soon as that is where the beverages will be stored.
Sunday, October 7, 2007
Achilles
I've been working on my collection of LCD displays. I had one that wasn't working properly and one that didn't work at all. I'm working on the wimpy one, but the dead one is back to life. I'm calling it Achilles for the reason that it was felled by one stupid little capacitor smaller than a pencil eraser.
Using the multimeter my grandpa Floyd gave me in 1994, I checked out the culprit capacitors as noted by this link and found C507 was clocking in at .5 microfarads in-circuit. It took me about half an hour to find anything with a replacement of the proper rating before I cannibalized one from the spare guts of a wireless Logitech controller. Soldering it with my ten year old Tenma station and the original ten year old tip was difficult, but it worked.
Testing the suspect capacitor out of circuit revealed the same .5 microfarad reading. You are the weakest link, goodbye.
Upon finishing installation of the cap and reassembly of the electronics, I plugged the display in to see a quick flash of the status LEDs and then a blank display with an amber power LED. Turning the display off then on yielded the Dell test pattern. It was working as far as the insides, but would it take a signal?
After gathering the hardware (which I had knocked off the top of a computer tower and scattered all over my messy floor) and putting everything back together, it was time to see if the display would... display... anything. With VGA output from the Alienware hot with an SXGA signal, I plugged in and powered up to see the desktop wallpaper and a rather dim display. Whoa. Low brightness setting? Nope, it's maxed in software.
As is the case with many displays that see duty in a college computer lab, this one had seen heavy use. And, being made in 2001, it had seen more than five years of it before I got hold of it for a dollar in broken form. I'm unable to access the factory menu to see an hour counter like the ones on my 1800FP and 2001FP, but I don't need the details to know this beast needs a re-lamping. I'll wait until I find a broken LCD I can't resurrect or get a few tubes for cheap before I do that piece of surgery.
Until then, I'll put this thing to use, yellowish display and all.
For the record, the panel in this is an LTM170E4 model which is an 8-bit per channel part. No dithering is used and all colors are directly addressed. Unlike my HP F1703, this one has a DVI port, too.
The F1703 is a good story to tell:
In 2004, my wife's grandma told me her LCD panel had just died. It would come on for a short moment and then the backlight would shut off, leaving a very dark image. She let me take it to see what I could do with it and I couldn't find anything obvious. She elected to order a new panel, which is still serving her well.
I figured the problem could be solved by purchasing a display of the same model with a cracked display panel off of ebay and transferring parts between the two. I ended up dropping about $90 on a panel with the middle third of the viewing space blacked out across the LCD. I figured I'd put the good LCD in the good case and call it a day, trashing the rest.
Wrong. I took the ebay display apart to find the components were completely different. Where grandma's display had a Chunghwa LCD, the ebay one had a Samsung. The LVDS connector was the same, but the backlight connectors were completely different, the Samsung having four where the Chunghwa had two. It was while putting the ebay panel back together that I noticed the black bar would come back intermittently. I figured I'd have a look inside deeper to see if I could find anything.
It was one of the control ICs driving the horizontal lines. There were three and the middle one was tweaked out of position, facing away from the others. Factory defect or not, I put the LCD module back together with the ribbon facing the correct way and fired the panel up. It worked. I gave it to Allison to replace her rather clunky Dell CRT, but after hooking it up, the bar was back so I gave it a whack and everything was fine. Has been ever since.
So the next LCD is a Gateway model that will run just fine for about half an hour and then go blank until power cycled. I'll post an update when I get to the bottom of that issue.
Using the multimeter my grandpa Floyd gave me in 1994, I checked out the culprit capacitors as noted by this link and found C507 was clocking in at .5 microfarads in-circuit. It took me about half an hour to find anything with a replacement of the proper rating before I cannibalized one from the spare guts of a wireless Logitech controller. Soldering it with my ten year old Tenma station and the original ten year old tip was difficult, but it worked.
Testing the suspect capacitor out of circuit revealed the same .5 microfarad reading. You are the weakest link, goodbye.
Upon finishing installation of the cap and reassembly of the electronics, I plugged the display in to see a quick flash of the status LEDs and then a blank display with an amber power LED. Turning the display off then on yielded the Dell test pattern. It was working as far as the insides, but would it take a signal?
After gathering the hardware (which I had knocked off the top of a computer tower and scattered all over my messy floor) and putting everything back together, it was time to see if the display would... display... anything. With VGA output from the Alienware hot with an SXGA signal, I plugged in and powered up to see the desktop wallpaper and a rather dim display. Whoa. Low brightness setting? Nope, it's maxed in software.
As is the case with many displays that see duty in a college computer lab, this one had seen heavy use. And, being made in 2001, it had seen more than five years of it before I got hold of it for a dollar in broken form. I'm unable to access the factory menu to see an hour counter like the ones on my 1800FP and 2001FP, but I don't need the details to know this beast needs a re-lamping. I'll wait until I find a broken LCD I can't resurrect or get a few tubes for cheap before I do that piece of surgery.
Until then, I'll put this thing to use, yellowish display and all.
For the record, the panel in this is an LTM170E4 model which is an 8-bit per channel part. No dithering is used and all colors are directly addressed. Unlike my HP F1703, this one has a DVI port, too.
The F1703 is a good story to tell:
In 2004, my wife's grandma told me her LCD panel had just died. It would come on for a short moment and then the backlight would shut off, leaving a very dark image. She let me take it to see what I could do with it and I couldn't find anything obvious. She elected to order a new panel, which is still serving her well.
I figured the problem could be solved by purchasing a display of the same model with a cracked display panel off of ebay and transferring parts between the two. I ended up dropping about $90 on a panel with the middle third of the viewing space blacked out across the LCD. I figured I'd put the good LCD in the good case and call it a day, trashing the rest.
Wrong. I took the ebay display apart to find the components were completely different. Where grandma's display had a Chunghwa LCD, the ebay one had a Samsung. The LVDS connector was the same, but the backlight connectors were completely different, the Samsung having four where the Chunghwa had two. It was while putting the ebay panel back together that I noticed the black bar would come back intermittently. I figured I'd have a look inside deeper to see if I could find anything.
It was one of the control ICs driving the horizontal lines. There were three and the middle one was tweaked out of position, facing away from the others. Factory defect or not, I put the LCD module back together with the ribbon facing the correct way and fired the panel up. It worked. I gave it to Allison to replace her rather clunky Dell CRT, but after hooking it up, the bar was back so I gave it a whack and everything was fine. Has been ever since.
So the next LCD is a Gateway model that will run just fine for about half an hour and then go blank until power cycled. I'll post an update when I get to the bottom of that issue.
Wednesday, September 12, 2007
X-ray Vision
I was trained on the X-ray inspection rig last night at work. I was given permission to x-ray circuit boards I bring from home as long as I work on them under the same conditions as before (breaks only).
With that in mind, I'm excited since I can finally see what the hell is wrong with the motherboard from my dead Thinkpad R40. I traced the problem to the area of the northbridge, but because I couldn't see anything, I couldn't fix it. It only had trouble when heated up and would work again with the right pressure on it so I'm thinking a microcrack someplace. It will be interesting to see the result of this.
I'm also looking at doing a bigger project, namely one of those 600MHz upgrades to one of my SGI O2 machines. Since I have the means necessary to do the work, I'm strongly considering it. All I have to do is get a bare RM7000C-600 CPU, one of those SPROM chips and training on the board oven and hot-air rework machines.
Right now, I can do the following to prepare:
switch the resistors around for the voltage mod
have someone at work remove the original CPU or teach me how
clean the pads for the CPU
remove the SPROM and clean the pads
wash the board in preparation for the new CPU and SPROM
If I can make this work efficiently, I could convert more.
With that in mind, I'm excited since I can finally see what the hell is wrong with the motherboard from my dead Thinkpad R40. I traced the problem to the area of the northbridge, but because I couldn't see anything, I couldn't fix it. It only had trouble when heated up and would work again with the right pressure on it so I'm thinking a microcrack someplace. It will be interesting to see the result of this.
I'm also looking at doing a bigger project, namely one of those 600MHz upgrades to one of my SGI O2 machines. Since I have the means necessary to do the work, I'm strongly considering it. All I have to do is get a bare RM7000C-600 CPU, one of those SPROM chips and training on the board oven and hot-air rework machines.
Right now, I can do the following to prepare:
switch the resistors around for the voltage mod
have someone at work remove the original CPU or teach me how
clean the pads for the CPU
remove the SPROM and clean the pads
wash the board in preparation for the new CPU and SPROM
If I can make this work efficiently, I could convert more.
Sunday, September 9, 2007
Antiquing - Geek style
Right now I'm using my Alienware laptop to do research on a relic I picked up from the local Deseret Industries store. It's a Compaq LTE/286 notebook computer. I'm familiar with this model because I've owned one twice before. The first time, it worked. The second time, it would never work again (I'm looking in your direction, David Orn. Coward.)
This one cost me all of $8 and included a battery pack I'm trying to bring back from the dead as I write this. The battery used in these is odd. It's a D-cell pack with four NiCd cells and a rating of 4.8V at 5Ah capacity. That's a pretty good rating for those days. The advantage with a NiCd pack is they pretty much have an indefinite lifespan as long as they're stored correctly. This one hasn't been, most likely, but I did give it a test boost from a 5VDC 2.5A switched-mode adapter. The adapter is fixed to 12W output, meaning in this case the voltage would drop in proportion to the current requirements. It was pushing 5A into the battery at 1.9VDC. Pretty normal for losses through the leads. I let it idle for a bit like that and then rubber-banded the leads in voltmeter style to check the pack voltage.
Half an hour into a creeping 1.95 to 2.16VDC reading, it jumped to 2.3, then 2.8 and now 3.34V. I am expecting the current input to the pack to be somewhere around 3A. The pack should reach 5VDC soon. The adapter's actual output is 5.25VDC so I won't have to worry about an abysmal charge rate toward the end.
What I don't know is whether the old pack will be able to put out the current I need. I tried to turn the system on with the feed from the adapter, but it would drop the moment the hard disk spindle started. Not unexpected, really. Those motors take a pretty hard kick to start up.
I have a battery case I remember making to power my wife's cellphone when her Lithium cell died. It was okay for that, but what I'm thinking about now more than anything is the fact that the pack is the size of a D-cell. It holds 4 AA cells. If I had four of them, I could run the system for a very long time from 16 NiMh AA cells. That would prove interesting since I have a way of connecting a charge circuit that would make the internal one obsolete.
More likely, I can just put eight AA cells in using packs I have around here already. I'd really much rather put NiMh D-cells in the old pack and alter the charge circuit, though.
My plan for the LTE/286 is to soup it up a bit. Granted, it's going to be nearly impossible to make it anything great, but I can at least make it a killer WordPerfect 5.1 system.
What I want to do, assuming it turns out to work:
1 - Replace the NiCd technology power system with a NiMh one
2 - Replace the EL backlight with an LED one, maybe with the addition of making the display transflective
3 - Replace the hard disk with solid-state Flash storage (very difficult)
4 - Add a keyboard light
5 - Upgrade the RAM
6 - Add some kind of off-storage in the expansion slot where the modem should be
7 - Drive the display as though it's color
1. Insanely easy. Most of the time, NiMh cells are direct replacements you just have to be a bit careful with when letting them charge for a long time.
2. A bit more involved, but the technology is there for an easy conversion. All I have to do is figure out how to spread the light in from the sides the best.
3. This could be a tough one. Some hard disks have to be typed as certain capacities. I'd likely be limited to a 128MB flash device, but that's fine. I already have one. The connector poses a problem as it's a 44-pin IDE connector with the wrong pin spacing. Not quite desktop and not quite notebook IDE.
4. I'm going to have to see if I can tie a Lock LED to a PIC or something to run it.
5. Upgrades are available. I can go to a maximum of 4MB more.
6. I don't know the pinout or whether anything high-speed is available, but I could find out with a lot of footwork.
7. The display used for these laptops is a weird one. I believe it was due to the technology allowing better contrast than the greyscale models. Black is actually a dark navy blue. White is actually an orange-ish white.
I'm now three hours into the project.
I have managed to use a 5VDC 3A power brick to run the computer. It was through this that I found I can connect the top right (from the back of the system) terminal of the power jack to 5VDC and connect the neutral to anywhere on the metal parts of the case in order to power the system just like a battery. I am unsure what the other two leads are for. Going directly from top to bottom or even reversing the polarity did nothing. Likely the neutral/system ground is common while one of the bottom pins is a positive for running the system. The adapter was rather complex with two outputs. I am guessing the system was kept light by keeping the charging system in the adapter.
While I had the system open, I looked for damage to the poorly designed hinges. It was there, especially on the left one, behind the battery pack. The way the hinge is fastened leaves a lot of flex in the stamped steel and with the hinge getting more stiff as it ages, damage is only a matter of time away. The posts where the hinge is anchored are cracked. One is almost gone. I rescued it with cyanoacrylate glue. What I'd really like is to have an epoxy resin buildup like I did with the last one.
I also discovered something that told a bit of the system's story. It was made here in the USA and the casing was molded in January of 1991.
I've discovered why the other LTE/286 had a burned hard disk cable, too. The cable for the drive is routed under the drive and over top of one of the mounting holes for bottom-mounting. The holes in question are not used on this system, with side mounting being the choice here. The mounting holes are, however, touching cushions inside the bottom piece when the system is assembled. That's machined aluminum on a Kapton ribbon cable. Not Kosher. I'm putting paper between the hole and ribbon. I will need that cable when it's time to swap drives.
It's now two days into the project. None of my adapters will properly charge the battery pack, but it wouldn't help, anyway. The pack is dead. It drops itself down to about 1VDC total soon after power is removed. I'll have to rebuild it. I'll also have to find an original AC adapter to do some reverse-engineering. I'd like to put a circuit inside the machine that will allow the system to take a normal two-wire power plug. The insides are rather packed, but it's still do-able with today's technology.
Honestly, what would really be cool is stripping the 286 gear out one day and installing something custom. I'd get a second LTE/286 for that, though. Properly reinforced, too.
I did boot the machine to find DOS already installed on a 40MB hard disk. WordPerfect 5.1 was also there. I don't remember how to use it so I've got a text editor called VDE on there. It's a good one.
This one cost me all of $8 and included a battery pack I'm trying to bring back from the dead as I write this. The battery used in these is odd. It's a D-cell pack with four NiCd cells and a rating of 4.8V at 5Ah capacity. That's a pretty good rating for those days. The advantage with a NiCd pack is they pretty much have an indefinite lifespan as long as they're stored correctly. This one hasn't been, most likely, but I did give it a test boost from a 5VDC 2.5A switched-mode adapter. The adapter is fixed to 12W output, meaning in this case the voltage would drop in proportion to the current requirements. It was pushing 5A into the battery at 1.9VDC. Pretty normal for losses through the leads. I let it idle for a bit like that and then rubber-banded the leads in voltmeter style to check the pack voltage.
Half an hour into a creeping 1.95 to 2.16VDC reading, it jumped to 2.3, then 2.8 and now 3.34V. I am expecting the current input to the pack to be somewhere around 3A. The pack should reach 5VDC soon. The adapter's actual output is 5.25VDC so I won't have to worry about an abysmal charge rate toward the end.
What I don't know is whether the old pack will be able to put out the current I need. I tried to turn the system on with the feed from the adapter, but it would drop the moment the hard disk spindle started. Not unexpected, really. Those motors take a pretty hard kick to start up.
I have a battery case I remember making to power my wife's cellphone when her Lithium cell died. It was okay for that, but what I'm thinking about now more than anything is the fact that the pack is the size of a D-cell. It holds 4 AA cells. If I had four of them, I could run the system for a very long time from 16 NiMh AA cells. That would prove interesting since I have a way of connecting a charge circuit that would make the internal one obsolete.
More likely, I can just put eight AA cells in using packs I have around here already. I'd really much rather put NiMh D-cells in the old pack and alter the charge circuit, though.
My plan for the LTE/286 is to soup it up a bit. Granted, it's going to be nearly impossible to make it anything great, but I can at least make it a killer WordPerfect 5.1 system.
What I want to do, assuming it turns out to work:
1 - Replace the NiCd technology power system with a NiMh one
2 - Replace the EL backlight with an LED one, maybe with the addition of making the display transflective
3 - Replace the hard disk with solid-state Flash storage (very difficult)
4 - Add a keyboard light
5 - Upgrade the RAM
6 - Add some kind of off-storage in the expansion slot where the modem should be
7 - Drive the display as though it's color
1. Insanely easy. Most of the time, NiMh cells are direct replacements you just have to be a bit careful with when letting them charge for a long time.
2. A bit more involved, but the technology is there for an easy conversion. All I have to do is figure out how to spread the light in from the sides the best.
3. This could be a tough one. Some hard disks have to be typed as certain capacities. I'd likely be limited to a 128MB flash device, but that's fine. I already have one. The connector poses a problem as it's a 44-pin IDE connector with the wrong pin spacing. Not quite desktop and not quite notebook IDE.
4. I'm going to have to see if I can tie a Lock LED to a PIC or something to run it.
5. Upgrades are available. I can go to a maximum of 4MB more.
6. I don't know the pinout or whether anything high-speed is available, but I could find out with a lot of footwork.
7. The display used for these laptops is a weird one. I believe it was due to the technology allowing better contrast than the greyscale models. Black is actually a dark navy blue. White is actually an orange-ish white.
I'm now three hours into the project.
I have managed to use a 5VDC 3A power brick to run the computer. It was through this that I found I can connect the top right (from the back of the system) terminal of the power jack to 5VDC and connect the neutral to anywhere on the metal parts of the case in order to power the system just like a battery. I am unsure what the other two leads are for. Going directly from top to bottom or even reversing the polarity did nothing. Likely the neutral/system ground is common while one of the bottom pins is a positive for running the system. The adapter was rather complex with two outputs. I am guessing the system was kept light by keeping the charging system in the adapter.
While I had the system open, I looked for damage to the poorly designed hinges. It was there, especially on the left one, behind the battery pack. The way the hinge is fastened leaves a lot of flex in the stamped steel and with the hinge getting more stiff as it ages, damage is only a matter of time away. The posts where the hinge is anchored are cracked. One is almost gone. I rescued it with cyanoacrylate glue. What I'd really like is to have an epoxy resin buildup like I did with the last one.
I also discovered something that told a bit of the system's story. It was made here in the USA and the casing was molded in January of 1991.
I've discovered why the other LTE/286 had a burned hard disk cable, too. The cable for the drive is routed under the drive and over top of one of the mounting holes for bottom-mounting. The holes in question are not used on this system, with side mounting being the choice here. The mounting holes are, however, touching cushions inside the bottom piece when the system is assembled. That's machined aluminum on a Kapton ribbon cable. Not Kosher. I'm putting paper between the hole and ribbon. I will need that cable when it's time to swap drives.
It's now two days into the project. None of my adapters will properly charge the battery pack, but it wouldn't help, anyway. The pack is dead. It drops itself down to about 1VDC total soon after power is removed. I'll have to rebuild it. I'll also have to find an original AC adapter to do some reverse-engineering. I'd like to put a circuit inside the machine that will allow the system to take a normal two-wire power plug. The insides are rather packed, but it's still do-able with today's technology.
Honestly, what would really be cool is stripping the 286 gear out one day and installing something custom. I'd get a second LTE/286 for that, though. Properly reinforced, too.
I did boot the machine to find DOS already installed on a 40MB hard disk. WordPerfect 5.1 was also there. I don't remember how to use it so I've got a text editor called VDE on there. It's a good one.
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