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LOGI Compact 286 (Rev. A) motherboard resurrection log

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First post, by Susanin79

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LOGI Compact 286 (Rev. A) — resurrection log

As promised in the “Bought these (retro) hardware today” thread, here’s a dedicated log for bringing a LOGI 286 motherboard back to life. This is one of the boards I recently picked up; it’s in better shape than the XT board, so I’m starting here. I’ll post diagnosis and repair progress in this thread.

Board

  • Model: LOGI Compact 286 Rev. A
  • Chipset: Texas Instruments TACT82301PB / TACT82302PB / TACT82303PB
  • CPU: Intel 80286 @ 10 MHz (PLCC68)
  • FPU: Intel 80287-10
  • ISA slots: 3× 16-bit, 1× 8-bit
  • RAM: 4× 30-pin SIMM
  • BIOS: 2× 16 KB 27128A (Award 3.03)

Initial inspection (microscope)
Not many issues overall, but a few could cause shorts or damage if left as-is:

  • 8-bit ISA slot: pins A2 and B2 are bridged.
  • Battery area: leaky connector; corrosion on the FPU socket and on SN74ALS32N (OR gate).
  • JP11: jumper torn off.
  • RN12: resistor pack with bent legs touching (short risk).
  • C64: tantalum cap with a broken lead → needs replacement.

What’s done so far

  • IC/chipset legs checked; solder looks good.
  • All bent pins straightened.

Next steps

  1. Verify AT PSU connector pinout and do a full short-check on power rails.
  2. Clean battery corrosion; socket/IC leg neutralization and rinse.
  3. Replace C64 and reinstall JP11.
  4. Minimal POST setup and begin jumper map.

I’ll keep this thread updated as the work progresses.

Reply 1 of 6, by Susanin79

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BIOS dumps (attached):

LOGI-286-HI_27128A@DIP28.BIN
LOGI-286-LO_27128A@DIP28.BIN

Reply 2 of 6, by PD2JK

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Hopefully you can find the missing IC's for that other board, the boards are looking stunning. As Ozzuneoj already stated, very Soltek-like, maybe they're affiliated?

i386 16 ⇒ i486 DX4 100 ⇒ Pentium MMX 200 ⇒ Athlon Pluto 700 ⇒ AthlonXP 1700+ ⇒ Opteron 165 ⇒ Dual Opteron 856

Reply 3 of 6, by pan069

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Cool boards. What might have happened to that 287? Almost looks like something had a nibble at it... 😀

Reply 4 of 6, by Susanin79

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PD2JK wrote on 2025-10-22, 18:27:

Hopefully you can find the missing IC's for that other board, the boards are looking stunning. As Ozzuneoj already stated, very Soltek-like, maybe they're affiliated?

I was able to find that “LOGICRAFT PRODUCTS” silkscreen points to Logicraft Products Manufacturing Pte Ltd, a Singapore-based company that sold PCs and parts under the LOGI brand around 1988–1991. Made “LOGI” laptops. The Singapore Business Times reported in Aug 1990 that Logicraft won a government design grant for their Logi 386SX laptop launched at CeBIT ’90.

Reply 5 of 6, by Susanin79

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pan069 wrote on 2025-10-22, 19:57:

Cool boards. What might have happened to that 287? Almost looks like something had a nibble at it... 😀

These boards were saved from a scrapyard, who knows how they were stored.

Reply 6 of 6, by Susanin79

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What’s been fixed/done since the last post

  • Cleared a hard short in the 8-bit ISA slot (pins A2↔B2 were bridged).
  • Straightened all bent pins, cleaned the board thoroughly.
  • Neutralized/washed battery leakage.
  • FPU socket was corroded, so I removed it (as soon as FPU is optional — will install a new socket later).
  • Desoldered the corroded SN74ALS32N (OR gate), cleaned its legs, and installed a fresh DIP socket (easy swap if needed).
  • C64 Tantalum capacitor was replace with a new one.

Hopefully most of the solder pads and traces survived. Only one trace came to JP9 need to be replaced. See the result on photo attached.
Unfortunately board didn't post at all. CPU looks shorted 🙁

Baseline measurements

  • +5 V rail: stable
  • CPU VCC (pins 30 & 62): ~4.92–4.93 V
  • RESET (pin 29): proper power-on pulse → then LOW
  • CLK (pin 31): ~20 MHz observed
  • POST card: all voltage LEDs on; CLK LED on; RESET LED pulses

So... it is as it is.

Board health otherwise looks promising so far. No shorts between +5 V and GND at the CPU and other sockets. Global RESET pulse present; main oscillator output is clean. Just needs a new PLCC-68 80286 to continue.
That is why I need to take a pause in this project as soon I have no spare CPU for now.

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