First post, by r00tb33r
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Hey all, long time no see.
I admit, it was an impulse buy. I was browsing the vintage section on the 'bay, and saw this. Google-fu produced no concrete specs for it, but I decided to take the plunge. Like most things labeled "good" that come with no power adapter you can expect an adventure...
Anyway, the exterior is immaculate, which is what caught my eye. It's like it was never used. When it arrived I was quite impressed by it, it was really nice to touch. Then I pried off the rear expansion cover and saw acid carnage... Then pried off the Ni-Cd battery pack, saw more battery acid carnage. There are screwdriver marks on some of the screws so I think the seller must have known. It was my risk, I took it, no fuss from me.
The machine shows no signs of damage on the outside so I decided to investigate if it's salvageable. I took the bottom case apart, disassembled everything and cleaned in an alcohol bath with a toothbrush. Miraculously the acid mostly missed the motherboard, it looks very promising. The unit is made in Japan, seems re-branded for Tandy. Lots of cool features inside, including a secondary "sleep" battery it seems. Acid mostly missed the FDD and the 60MB HDD. FDD seems fine, I lightly cleaned the heads with a Q-tip and alcohol, just in case. FDD uses an FPC type flat flex cable soldered to the drive. On the motherboard end the pins started to de-laminate from the connector edge, failing adhesive it seems, I hope to super-glue them flat to the connector, but I won't touch this drive until I'm ready to reassemble, it won't survive multiple insertions. Conner CP-2064 2.5" HDD looks good externally, I have cleaned the PCB, but I have not gotten it to work hooked up to my modern PC, it spins up and spins down, but I hear no head activity, also not being detected, what seems to be the spindle controller is very hot when it spins up. This is kind of sad, because I was hoping to get original utilities and drivers off it. I guess I'll have to find a suitable replacement unless someone here has an idea how to revive it. Acid damage is mostly limited to the EMF shielding paint on the inside of the laptop body, and the cage around the HDD.
The motherboard is a DFUP0462ZAB1 on silkscreen, DL3UP0462CAA1 on barcode sticker. Made in Japan. Uses a Harris CS80C286-16 licensed from Intel in a PLCC socket, with a Headland HT18/A chipset. VGA is Cirrus Logic parts, CL-GD610 and CL-GD620. There is an unpopulated PLCC socket for a 387SX and unpopulated board position for a 386SX (and possibly a 486SLC) in a through-hole 100-pin QFP socket. I have socket part numbers. Seems all passives around there are populated, so the upgrade to a 386/486 should theoretically be possible, but not sure if practical for reasons I'll explain. There is a 32MHz oscillator overlapping a position for a possible 40MHz (labeled) oscillator, a bit confusing, I have not traced it out yet.
It uses a 16V 1.25A power adapter. The connector is fancy for historical reasons I understand, but the board pads are standard, so I'll replace it with a standard 5mm barrel jack when I get around to it. I soldered wires to the pads so I could power it up with one of my 16V Toshiba adapters. I started with just the motherboard, speaker and the LED/button board. LEDs flicker on and it even beeps sometimes. I connected the screen and it did flash. I hear some whine from the board when it tried to power on. Some of the caps looked suspect. I decided to re-cap it, was like $15 all-in from DigiKey. It was a messy job, the SMD caps were glued to the PCB from the underside, part of the placement process during production I guess. I learned to crack the glue first before de-soldering. I think I lost a pad on 4 or 5 of them, still managed to solder to vias or remaining traces. I'm not exactly a total rookie, this board was not good to rework. Not sure if I would have had more luck with hot air. In any case, the recap is done. It powered up and attempted to boot. There was BIOS boot messages on the screen, I was ecstatic. Reported 1MB of RAM. CMOS contents were lost, said to run the SETUP program, there was no prompt for a key, not sure if it has a ROM program or I have to run a vendor program from a disk. Keyboard is not connected right now because the ribbons are very delicate, I don't want to connect them too many times. I should try the PS/2 connector next time, probably.
Uses a Dallas DS1287... It's probably bad now, right?
There is a 50 pin connector for a memory expansion module. I have not yet identified that connector type, I have seen it on Dell drive bays before.
There is a rear expansion connector on the motherboard labeled MOD, 18 pins for an FPC flex like the FDD, it lives next to the battery under a plastic cover wit a knock-out sized for an RJ-11. I presume that was for a modem. I'm more interested in whether I could put an AdLib clone in there, if that's even sensible. But would be cool. Any info on that connector?
The screen... The lid is immaculate. The panel turned out to be monochrome, I really wished for color, to be honest. But okay. Seems to be a passive matrix, has a contrast slider, kind of slow to fade in with some light line streaks when some of the pixels are changed. I could get that contrast pretty good. Backlight seemed okay, more or less. After a couple of minutes working I started to see flickering, and the pixel matrix started to get darker, until I could barely see the text. The text is still there, I can faintly see the outline of it. Backlight is still working as the border around the pixel matrix is brighter. It's like the contrast control suddenly failed. Has anyone else seen something like this happen? This is where I need help with right now, I know too little about these old monochrome screens. I did not pry apart the lid yet, as it's immaculate and I see no obvious screw holes. Going to wait for comments first.
What would I do with it? Pretty much like all my vintage gear, I don't really know. The main issue here is probably the monochrome screen. It's a cool project but I don't see how a 386sx or a 486slc would be a good pairing with a monochrome screen. That chipset supports up to 8MB RAM. I presume if 1MB is on the board, probably the expansion is 4MB, for 5MB total...? Probably not even sensible for a 486-class machine, and I don't really know what good a 386sx is vs a 286. With a 286 it probably doesn't make sense to seek more memory, even if I can either find or make that memory expansion. What do you guys think? What is this thing good for?
I can probably re-cell the battery, unless there are better ideas. I was thinking of using Ni-Cd AA-sized rechargeables in a holder, seems they would fit inside the battery compartment. They are not expensive.
I would really appreciate resources and info on this model and in what direction to take this project. Right now I need help with the screen.
PS, it seems VOGONS changed the forum theme since I was here last. This theme is very hard to read, very hard on the eyes. Any way to switch to the older one? I switched to classic colors but the theme fonts and stuff are still not good for readability.