VOGONS


First post, by stopi

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I try to run HLH386SX motherboard. Brand Nic Technology https://stason.org/TULARC/pc/motherboards/N/N … 6-HLH386SX.html. I have:

- 386SX-25 motherboard on Headland HT18/B chipset
- Cirrus Logic CL-GD5401-42AC card
- ATX power supply with self-made connector for AT slot
- standard VGA LCD monitor with D-SUB cable
- POST codes card
- 2 SIMM-30 modules (3-chip 1MB each)
- BTC keyboard

Power is starting after green-black connection in ATX cables. POST card shows "FF.."

I checked voltages. There is +12, +5, -12, -5, PWR_GOOD is about 5V. +5V is present on most important circuits on motherboard and ISA cards.

3 diodes on the keyboard are lighting. Nothing happens. I tried to place VGA card to other ISA slot. No result. I tried to run with only 1 memory module. I doesn't start. Keyboard BIOS is warm (but maybe it's normal..). Maybe memory is problem - there should be 9-chip modules but I placed 3-chip simms. I don't have speaker actually and I can't hear if something is buzzing....

I remember that motherboard was working.

I have oscilloscope and programmer. Maybe I should to check BIOS? What about crystal oscillators after 25 years without usage?

Reply 1 of 9, by mkarcher

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You have a scope. You could use it to to probe the speaker line. I don't expect to get beeps with no display of non-FF codes on the POST card.

The last 386SX board I revived had a broken trace causing a missing address bit on the ROM bios. Use your scope to probe the processor clock and ROM BIOS address and data pins. Watch out for strange waveforms (indicating floating inputs) and constant levels on signals that are unlikely to stay constant.

Reply 2 of 9, by kalohimal

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You need 4 pieces of SIMM-30 to work, 2 pcs won't work and neither would 1. For speaker, your POST card has one onboard, all you need is a wire to connect it up (which should come with your POST card). Btw, it horrifies me to see direct soldering onto the AT connector.

Slow down your CPU with CPUSPD for DOS retro gaming.

Reply 3 of 9, by Anonymous Coward

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On a 386SX, you normally just need two 30-pin SIMMs, as your external databus is only 16-bit. However, I have seen 386SX boards that interleave the DRAM banks that do require 4.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 4 of 9, by kalohimal

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Oops me bad, was thinking 486. Yeah 2 pcs SIMM would work for this board.

Slow down your CPU with CPUSPD for DOS retro gaming.

Reply 5 of 9, by Miphee

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That soldering job with all the wires tangling left and right... brrr.
And what's with the strange wire colors? Red, orange and blue as GND?
What about beep codes? Get a speaker.
Get rid of that "PSU" and get a standard AT PSU first.

Reply 6 of 9, by stopi

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PSU is working fine. It's PSU originally with 24-pin ATX connector and voltages are stable. Colors has no matter but connections I made are compatible with AT pinout. Checked with multimeter. There are 4 GND pins, 4 +5V pins and others... If it will start I will mount standard AT connector. Now it's only for a try.

Ok. I will check something more with scope and let You know what's going on. I have inserted BIOS chip into programmer and there seems to be ok.

What is keyboard controller/bios chip there? I didn't reveal marking under sticker yet.

I guess that memory type can be a problem. There are recommended 9-chip modules instead of 3-chip.

Reply 7 of 9, by stopi

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One question: what are -5V and -12V lines for? Most of chips are +5V powered.

Reply 8 of 9, by Vynix

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The "-5V" is for some ISA cards (such as the Soundblaster 2.0 CT1350B) that require it. Some mobos allegedly require it as well but not all of them do. Some DRAM chips also required it

The "-12V" was used for RS-232 (iirc), though I can't find reliable information as to what the negative 12V rail was used for.

Proud owner of a Shuttle HOT-555A 430VX motherboard and two wonderful retro laptops, namely a Compaq Armada 1700 [nonfunctional] and a HP Omnibook XE3-GC [fully working :p]

Reply 9 of 9, by matze79

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Some Cards require -5/-12V for OpAmps for example.

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