VOGONS


First post, by 133MHz

User metadata
Rank Oldbie
Rank
Oldbie

Today at the usual flea market I picked up a Compaq LTE/286 laptop, no accessories, but for a mere $2 I couldn't say no! 🤣 Aside from being dirty and missing the side covers it seems to be in good cosmetic condition.

I couldn't find the AC adapter specs (voltage/current/pinout) but I found out that the battery input takes 4.8V @ 5A, so I hooked it up to the +5V rail of an AT PSU to test it out. The hard drive spins up, but the power LED lights up for a split second and the computer itself stays dead. I unplugged the hard drive and the computer sprung back to life, but with the following symptoms:

  • No backlight.
  • Audible DC-DC SMPS squealing, varying in pitch with the display contrast setting.
  • BIOS throws up 601 Diskette controller error in conjunction with the usual dead CMOS battery issues.
  • Can't get it to boot off a floppy, no floppy access is being made by the system, and when a disk is inserted one of the motors runs continuously until said disk is ejected.

I had a closer look at the motherboard and noticed corrosion on the legs of almost every capacitor, suggesting electrolyte leakage a la Sega Game Gear (even the caps look physically similar to those of the GG). Does this mean that the Compaq LTE/286 suffers from capacitor plague like some Macintosh logic boards? I didn't find any mention of capacitor problems on these machines, and I find it hard to believe that mine is the only one like this.

lte286_badcaps.jpg?w=600

My plan is to recap the board with cheap 'lytics and hope that fixes the FDC issue. Since this is one of those Compaq machines where you need a setup disk to configure the CMOS, I guess that if the FDC is toast then the entire machine is done for. 😢

http://133FSB.wordpress.com

Reply 1 of 19, by matze79

User metadata
Rank Oldbie
Rank
Oldbie

any progress ?

https://dosreloaded.de - The German Retro DOS PC Community
https://www.retroianer.de - under constructing since ever

Co2 - for a endless Summer

Reply 2 of 19, by Logistics

User metadata
Rank Oldbie
Rank
Oldbie

Oh, man! Even if you replace capacitors, you gotta get that junk off the motherboard--there is way too much oxidation and corrosion going on. I would be tempted to use some sort of agent to get rid of it.

The long, arduous way would probably be to use a white-vinegar and water mix, and a toothbrush to slowly get rid of it all. I would remove all the capacitors which you intend to replace, first. If the board was in MY possession, I would use ZEP Acidic Toilet Bowl Cleaner. I use it all over my house to get rid of the calcium build-up on the toilet, sinks, tub, faucets, etc. It also cleans up copper and brass in a hurry. I wouldn't leave it on for long as it probably wouldn't be good for something in the long-term, but the board needs to be washed, anyway so I would do a section, rinse, do another section, rinse, etc., then let the board dry out and recap it.

Reply 3 of 19, by Asaki

User metadata
Rank Newbie
Rank
Newbie
133MHz wrote:
  • Can't get it to boot off a floppy, no floppy access is being made by the system, and when a disk is inserted one of the motors runs continuously until said disk is ejected.

If it's anything like the LTE Elite, the belt inside has turned into dust. I have to put the HDD into a different laptop, or use my PCMCIA CF card adapter if I want to install anything.

Reply 4 of 19, by 386_junkie

User metadata
Rank Oldbie
Rank
Oldbie

Just replace the caps, and maybe give the board a clean... you'll find pretty much all functions will return back to normal. It is these caps that drive most (if not all) the system... if they leak, the system ain't getting the juice!

Compaq Systempro; EISA Dual 386 ¦ Compaq Junkiepro; EISA Dual 386 ¦ ALR Powerpro; EISA Dual 386

EISA Graphic Cards ¦ EISA Graphic Card Benchmarks

Reply 5 of 19, by matze79

User metadata
Rank Oldbie
Rank
Oldbie
Asaki wrote:
133MHz wrote:
  • Can't get it to boot off a floppy, no floppy access is being made by the system, and when a disk is inserted one of the motors runs continuously until said disk is ejected.

If it's anything like the LTE Elite, the belt inside has turned into dust. I have to put the HDD into a different laptop, or use my PCMCIA CF card adapter if I want to install anything.

This damn Compaq needs to load its setup program from floppy to setup bios settings.. 😳

https://dosreloaded.de - The German Retro DOS PC Community
https://www.retroianer.de - under constructing since ever

Co2 - for a endless Summer

Reply 6 of 19, by 133MHz

User metadata
Rank Oldbie
Rank
Oldbie

Wow, didn't realize this was almost two years ago! 😳
From what I remember, when I began to clean up the board from the electrolyte residue several traces and vias started disintegrating due to the advanced corrosion, traces/vias so fine you'd need a single strand of fine copper to be able to repair them. I handed the board over to a friend who is more skilled than me at precision soldering, since it was only a favor it's probably still sitting on his 'pending' pile to this day.

I'm afraid it's probably too far gone at this point, if the corrosion managed to get into the intermediate layers through the vias and whatnot any efforts of cleaning, bridging and recapping might end up wasted.

http://133FSB.wordpress.com

Reply 7 of 19, by matze79

User metadata
Rank Oldbie
Rank
Oldbie

The backlit on all units i have doesnt work.
I have 3 LTE's sitting here a LTE and 2x LTE/286

The floppy uses a belt, which needs to be replaced if it doesnt work anymore

https://dosreloaded.de - The German Retro DOS PC Community
https://www.retroianer.de - under constructing since ever

Co2 - for a endless Summer

Reply 8 of 19, by matze79

User metadata
Rank Oldbie
Rank
Oldbie

Compaq LTE:
file.php?id=6313

Compaq 286LTE:
file.php?id=6314

Trying to Fix 286LTE:file.php?id=6317

file.php?id=6318
Soldered small wires on the tracks and run a wire from top to back (broken VIA).

i have now four of this compaq's.. 3 aluminium caps are leaking (always same 3) or burnt (short circuit)
leading into broken VIA's, broken pcb tracks

My boards are different from yours, i have less aluminium caps inside 😳

https://dosreloaded.de - The German Retro DOS PC Community
https://www.retroianer.de - under constructing since ever

Co2 - for a endless Summer

Reply 9 of 19, by matze79

User metadata
Rank Oldbie
Rank
Oldbie

file.php?id=6400

I got the Backlight working, unfortunally it don't won't boot from floppy, i already tried a different drive with new belt.
But no success, maybe the drivehead is bad.

All LTE's 8086 suffer from heavy capacitor leaking... i have two now. And both are really gone.
Even the Floppydrive has leaking Capacitors..

https://dosreloaded.de - The German Retro DOS PC Community
https://www.retroianer.de - under constructing since ever

Co2 - for a endless Summer

Reply 10 of 19, by ultimate386

User metadata
Rank Member
Rank
Member

Wow, I had a LTE/286 about 10-15 years ago that had practically the exact same patch of dead pixels on the screen when I bought it on eBay. Fortunately I was able to find a NOS replacement screen on eBay as well! Alas, I ended up selling the system, carrying case and all, for all of $25 back on eBay when the power supply died 😢 .

AMD386/IIT387DX40, 32MB, ATi Mach64, AWE64
Compaq Prolinea 4/33, 32MB, Tseng ET4000, SB16
AMD X5, 64MB, S3 Virge/Voodoo1, AWE64
AMD K62+550, 256MB, Voodoo3, AWE64 Gold
P3 1.2Ghz, 512MB, Radeon 7500/Voodoo2 SLI, SB Live!

Reply 11 of 19, by matze79

User metadata
Rank Oldbie
Rank
Oldbie

I got another LTE/286 working:

file.php?id=6451
file.php?id=6453

More Pictures here:
http://www.dosforum.de/viewtopic.php?f=29&t=1 … start=15#p64717

Same VIA defective as above, same capacitors.
All others make a nice fish smell..
need a replacment for them too. Hopefully they don't contain PCB poison.. 😳
Unfortunaly they are soldered and glued to the pcb..
so its not easy to get them offboard

(Please correct me, if my english is wrong, grammars suffer.. i tend to use it like german words.)

https://dosreloaded.de - The German Retro DOS PC Community
https://www.retroianer.de - under constructing since ever

Co2 - for a endless Summer

Reply 12 of 19, by Zack_H

User metadata
Rank Newbie
Rank
Newbie

I repaired an LTE 8086 and an LTE/286 recently! Both had the backlight failure problem, and both had rotted vias and traces. Spent many hours on them! It truly is a labor of love for me. These laptops really aren’t worth much, but they bring me a lot of joy, so it was well worth it! 😀

Here’s the 8086:

CD0DAABC-D576-425C-8F02-1A622D4B8A12.jpeg
Filename
CD0DAABC-D576-425C-8F02-1A622D4B8A12.jpeg
File size
1.05 MiB
Views
484 views
File license
Fair use/fair dealing exception
3D7B7A11-85D7-4431-9EAC-C618B785CBE4.jpeg
Filename
3D7B7A11-85D7-4431-9EAC-C618B785CBE4.jpeg
File size
829.32 KiB
Views
484 views
File license
Fair use/fair dealing exception
F4004E36-4254-40D0-A0FA-A339F801AF20.jpeg
Filename
F4004E36-4254-40D0-A0FA-A339F801AF20.jpeg
File size
819.84 KiB
Views
484 views
File license
Fair use/fair dealing exception
8A2EE107-3518-4B48-8DD5-D7248070C696.jpeg
Filename
8A2EE107-3518-4B48-8DD5-D7248070C696.jpeg
File size
604.88 KiB
Views
484 views
File license
Fair use/fair dealing exception

Starting Windows 95. . .

Reply 13 of 19, by 386_junkie

User metadata
Rank Oldbie
Rank
Oldbie

This is great to see folk reviving these little old LTE's/SLT's with the various issues they are having with age. Just recently I refurbished an old PSU module as the LTE wasn't powering on with the transformer / charger. It turned out it was one of the diodes in the power transistor! Though still, as a matter of course, I will need to soon replace the caps.

I too can't believe this thread was from 2 / 3 years ago, why I saw my post I was like... "from when was this!"

Hopefully your friend will help sort you LTE... even just the floppy so it will help get you going at least.

Compaq Systempro; EISA Dual 386 ¦ Compaq Junkiepro; EISA Dual 386 ¦ ALR Powerpro; EISA Dual 386

EISA Graphic Cards ¦ EISA Graphic Card Benchmarks

Reply 14 of 19, by Zack_H

User metadata
Rank Newbie
Rank
Newbie

Indeed! We have to preserve these pieces of computer history! 😀

Here’s the LTE/286 that I repaired:

1E7F0EF4-F50A-42D3-8114-E51FE0E96369.jpeg
Filename
1E7F0EF4-F50A-42D3-8114-E51FE0E96369.jpeg
File size
1.2 MiB
Views
463 views
File license
Fair use/fair dealing exception
B5570C70-8FEA-49D9-AC1D-57874DBD2F62.jpeg
Filename
B5570C70-8FEA-49D9-AC1D-57874DBD2F62.jpeg
File size
994.77 KiB
Views
463 views
File license
Fair use/fair dealing exception
1530845D-8269-42D8-B25E-E6071B7EB7D2.jpeg
Filename
1530845D-8269-42D8-B25E-E6071B7EB7D2.jpeg
File size
630.06 KiB
Views
463 views
File license
Fair use/fair dealing exception
DD5E61D4-FD9E-4FBB-BE6B-49E1734EB511.jpeg
Filename
DD5E61D4-FD9E-4FBB-BE6B-49E1734EB511.jpeg
File size
687 KiB
Views
463 views
File license
Fair use/fair dealing exception

Starting Windows 95. . .

Reply 15 of 19, by peido

User metadata
Rank Newbie
Rank
Newbie

Well done. It's really good to see people spending so much time to preserve this nice computers.

I hope some day I will get the time required to restore my SLT and my LTE's to former glory, but until then it's always good to see the success of other people.

Reply 16 of 19, by retardware

User metadata
Rank Oldbie
Rank
Oldbie

just a suggestion:
take some coil or transformer with matching wire size and use it as patch wire donor.
This looks much tidier than using these thick cables with even thicker insulation plastics that make your restoration efforts look really crude - which they are not.

Reply 17 of 19, by root42

User metadata
Rank Oldbie
Rank
Oldbie

I am impressed by the amount of work and love that you guys put into those machines! Great restoration and preservation effort!

YouTube and Bonus
80386DX@25 MHz, 8 MiB RAM, Tseng ET4000 1 MiB, SnarkBarker & BlasterBoard, PC MIDI Card + SC55 + MT32, XT CF Lite, OSSC

Reply 18 of 19, by Zack_H

User metadata
Rank Newbie
Rank
Newbie

Thanks everyone!

Yeah, these patch wires don’t exactly look the best, but I’m really not in the slightest concerned about it, as it’s hidden inside the machine 😀 Appreciate the suggestion though!

Starting Windows 95. . .

Reply 19 of 19, by befi

User metadata
Rank Newbie
Rank
Newbie

Hi Zack

Very nice restoration, congrats!

This weekend I picked up the same machine from the flea market and of course it suffered from exactly the same problem: Leaking caps. After replacing them the situation got worse than better. Upon closer inspection I noticed that the electrolyte dissolved several tracks on the upper side of the IO board as well as one trace on the bottom where the liquid sipped through a via.
And these vias are exactly my issue: These are gone as well on the outside, so I cannot trace to where the signals were going (in case of vias that connect only to internal layers on one side).

I was able to fix most of the connections but one is giving me trouble: The one that you also fixed with a red patch wire, close to the multi-pin-connector between the two caps going to the big compaq IC. I traced the right side of the track (my via is still there) to reach exactly the big IC to where you wired your patch signal. The other side of the track is however so far gone (both sides of the via) that I have no way of measuring to where it originally connected. Do you still roughly remember where this track was going? Or maybe you have your LTE currently open are able to measure?

Best regards,
Ben.