Fixing BTC 1817DW \ VOGONS

Fixing BTC 1817DW

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First post, by r00tcz

Posted on 2026-03-01, 16:57

r00tcz Offline

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Rank: Newbie
Posts: 6
Joined: 2026-02-01, 00:38

Hi,

Got this ISA soundcard but it's in pretty bad shape, someone took out a few components out of it and PCB is badly scratched in a few places...
I can fix the PCB tracks but I need some help with missing components, here in the red on the TheRetroWeb photo:

The attachment missing.jpg is no longer available

U7 is missing, I guess it's some voltage regulator in classic 3 legged package. It looks to be present on all similar OPTI cards, but I can't find any photos from the side to read the markings.
Two SMD caps C85 and C11, not sure if they are simply decoupling caps or something more important. I will probably desolder C83 and C10 to measure them and get same values as a replacements.
Then there are two XTALs: 14.31818MHz for the OPTI chip and 24MHz for the wavetable DSP, may have both in my junk pile (first is 4x NTSC carrier and 24MHz is very common in USB things)

So just need help with that U7...

Reply 1 of 5, by Pave99

Posted on 2026-03-01, 19:44

Pave99 Offline

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Joined: 2018-07-27, 09:00

Hi!

I've got two of opti 931 cards, but they both have different regulators there.

The first one is a red ULC933D that has a regulator U5 with markings:

78L05
Y9735

The second one is a green unbranded one that has a regulator U11 with markings that are bit unclear:

KA7HL
05AZ (?)
032 (?)

See attached images. I can also provide more images if you need. Hope this helps!

Reply 2 of 5, by weedeewee

Posted on 2026-03-01, 20:11

weedeewee Offline

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Pave99 wrote on 2026-03-01, 19:44:
Hi! […]
Show full quote

Hi!

I've got two of opti 931 cards, but they both have different regulators there.

The first one is a red ULC933D that has a regulator U5 with markings:

78L05
Y9735

The second one is a green unbranded one that has a regulator U11 with markings that are bit unclear:

KA7HL
05AZ (?)
032 (?)

See attached images. I can also provide more images if you need. Hope this helps!

Looks to me like they're both 78L05 , 5v regulators, with the font on the odd one screwing up the 8 and turning it into what looks like an H.

Right to repair is fundamental. You own it, you're allowed to fix it.
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Reply 3 of 5, by r00tcz

Posted on 2026-03-01, 21:23

r00tcz Offline

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Rank: Newbie
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Joined: 2026-02-01, 00:38

Thanks!
Yes, 78L05 was my guess too.

Reply 4 of 5, by Matth79

Posted on 2026-03-01, 21:27

Matth79 Offline

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Joined: 2014-05-19, 14:24

If parts were being salvaged, that probably does not bode well - unless its temporary for testing something else, you don't usually salvage parts from a working card

Reply 5 of 5, by r00tcz

Posted on 2026-03-04, 22:27

r00tcz Offline

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Rank: Newbie
Posts: 6
Joined: 2026-02-01, 00:38

Matth79 wrote on 2026-03-01, 21:27:

If parts were being salvaged, that probably does not bode well - unless its temporary for testing something else, you don't usually salvage parts from a working card

Yeah... well, I soldered new XTALs and voltage regulator and gave it a shot... nothing. Checked the power on VCC pins, all good, crystals are oscillating but no luck with BTC DOS utility or HWINFO, no ISA card detected at all. I will inspect the PCB again under a microscope in case I missed something but this one doesn't look very promising...

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