VOGONS


First post, by Overlord_Manny

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I figure I'm having PSU issues, but I figured I pick other people's brains and see if anyone had similar issues.

I have 2 machines a socket 7 with a GA-586ATX MB and a P233mmx, and also a socket 3 with a AM486DX2, not sure about the MB on this one(edit: It's a 486VLG-X4). I have a sound card issue with an ATC-6631 that has a YMF719e chip.

The card works perfectly fine in the Pentium system both in DOS and Windows 95, I have played Warcraft 2 for hours with it and windows 95 sounds have never dropped out.

In the 486 the card will work and test fine for a while but then the WSS side craps out suddenly. Sometimes it will work for a whole day or so and sometimes for a few minutes. After that I get no wave sound in windows and setupsa.exe pressing 'W' to test the WSS I get static. All other sounds work fine during this WSS failure. Rebooting does not fix the problem but sometimes after leaving the system off for a day or so it will start working again. Thinking the card was bad, (before putting it in the Pentium to test), I replaced Ecaps with good quality caps and also changed the 78L05 regulator. It seems maybe I have either a PSU or a MB issue. I'm gonna recap the PSU because it's OLD and has it's original caps. Anyone have similar problems?

Last edited by Overlord_Manny on 2019-08-20, 19:13. Edited 3 times in total.

Reply 1 of 12, by cyclone3d

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Sounds to me like the PSU or possibly the ISA slot connector you are plugging it into is oxidized/dirty.

Easiest way I have found to clean the slots is to fold up a piece of printer paper thick enough so there is a bit if resistance when inserting it into the slot.

The insert it and remove it a bunch if times until it stops coming out with black lines on it. You will probably have to refold and/or use multiple pieces of cut to size paper.

Back in the day you could get those cart style game system cleaning kits and those worked just as good.

Yamaha YMF modified setupds and drivers
Yamaha XG resource repository - updated November 27, 2018
Yamaha YMF7x4 Guide
AW744L II - YMF744 - AOpen Cobra Sound Card - Install SB-Link Header
Epstein didn't kill himself

Reply 3 of 12, by Overlord_Manny

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cyclone3d wrote:
Sounds to me like the PSU or possibly the ISA slot connector you are plugging it into is oxidized/dirty. […]
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Sounds to me like the PSU or possibly the ISA slot connector you are plugging it into is oxidized/dirty.

Easiest way I have found to clean the slots is to fold up a piece of printer paper thick enough so there is a bit if resistance when inserting it into the slot.

The insert it and remove it a bunch if times until it stops coming out with black lines on it. You will probably have to refold and/or use multiple pieces of cut to size paper.

Back in the day you could get those cart style game system cleaning kits and those worked just as good.

I've tried different slots with no difference made. I'll clean the slots when I get home though to rule that out. I have polished the contacts of the card with a fiberglass pen.

Is the ISA bus on the AM486DX2 system perhaps running out of specs? Ideally, it should run at 8.33 MHz.

I have an oscilloscope. I can check it out. I would think I'd have more problems than just the sound card if that were the case.

Also, maybe unrelated/maybe not the CD audio from games like Warcraft 2 is very, very quiet on the 486 and it's not on the Pentium. That could be the CD drive though. I'll swap them too and see if the problem there follows.

Reply 4 of 12, by derSammler

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I have an oscilloscope. I can check it out.

That's something you set in the BIOS depending on the system clock. No need for an oscilloscope. If the DX2 is running at 66 MHz (33 MHz FSB), the option for the ISA bus speed should be 1/4.

Also, maybe unrelated/maybe not the CD audio from games like Warcraft 2 is very, very quiet on the 486 and it's not on the Pentium.

Check the mixer settings. CD audio has it's own volume control and may just be set much lower on the 486.

Reply 5 of 12, by jaZz_KCS

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Nice to see another GA-586ATX board found a good home. Keep it safe, it is one of the fastest FSB66 Socket 7 boards in existence.
The newest BIOS lets you even run an AMD K6-2 up to 400Mhz, if that is one's fancy.

Reply 6 of 12, by Overlord_Manny

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Oh... Haha When I think out of spec I think of components out of tolerance. I know the ram is set at 1/4CLK. I'm not sure if my bios has an option for the ISA bus speed. I remember a setting with options of, I think, 4Mhz or 8Mhz but I'm not sure what it was from my memory. It defaulted to 4Mhz though I'm pretty sure and I left it at that. Would be an awesome if that's the fix.

As for the CD audio, I have it maxed out at seven in the setupsa.exe mixer and in the game. It's still inaudible unless I crank my receiver to max volume.

Reply 7 of 12, by Overlord_Manny

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jaZz_KCS wrote:

Nice to see another GA-586ATX board found a good home. Keep it safe, it is one of the fastest FSB66 Socket 7 boards in existence.
The newest BIOS lets you even run an AMD K6-2 up to 400Mhz, if that is one's fancy.

It's a great board for sure. I'm quite happy with it. I had it sitting in a closet for years. Someone gave it to me with a bunch of "Junk" parts that I also still have.

I currently have it running Win95 with 256Mb of ram, an AWE 64 Value w/simmcon, a S3 Virge DX, and an Orchid Voodoo 1 card. Good stuff

Reply 8 of 12, by Overlord_Manny

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Ok, I checked out my BIOS settings. AT Bus is set at 1/4 and has been, it's right above the ram settings in the bios and if I enable auto config for the ram it locks at 1/4. The setting with 4Mhz or 8Mhz is the DMA Clock which is at the default of 4Mhz. I also cleaned the ISA ports, they really didn't have much grime on them, hard to know for sure if it's effected anything at the moment because the card has been working fine since yesterday evening.

Reply 9 of 12, by Overlord_Manny

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After 3 days of working fine, now the ADLIB sounds won't play consistently. WSS is working though. After a couple of boots where my hard disk (CF card actually) wasn't found, I decided that I have to be having a power issue. I pulled the motherboard to check the power pins because I felt they flexed a bit too much. They were fine though, it was only the plastic part of the connector flexing. I opened up the PSU again. I had opened it when I originally got this computer about a month ago and cleaned out the dust bunnies. Caps that weren't leaking before are leaking a bit now. Fuhiyyu is not a brand known for their longevity anyway. I ordered a full set of replacement NICHICON caps and also an ATX to AT adapter cable as well for further testing.

Reply 10 of 12, by Overlord_Manny

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The replacement caps I ordered haven't come in yet but I did get the atx to at adapter. Looks like the psu may have been the issue. Even the cd audio sound is louder. This has been an intermittant problem though so I hate to jinx myself and say it's solved, but it's all working great right now.

Reply 12 of 12, by jaZz_KCS

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Overlord_Manny wrote:

I didn't want to just leave this open. I replaced all the caps in my AT PSU and It fixed all the weird issues with my sound card. May it last another 30 years.

Optimistic, but hopefully.