Do you have leaky caps on your mainboard?

not a single visible leaky cap from what i see

Hi,

I assume that you have checked for leaky caps on the card also not just only the motherboard.

There are some other things that can be checked according to the symptoms:
1. Bad solder joints on the components related to digital output on the card, making intermittent connection(Explaining why the sound goes from non-existent to distorted to actually working good. Checking every solder joint is a bit of pain though.)
2. Maybe an overheating issue, compare the temperature of the card's main ICs when the issue happens and when it doesn't, you can either use a remote thermometer or an IR camera to do that when the computer case is opened.

Less probable causes:
1. Bad connection with the ISA slot. (Unlikely, as that would most likely also effect the OPL3 voices too)
2. DMA transfer error from the motherboard. (Unlikely as that would explain the no sound, and in some cases the high scratching static noise, but not the low sound scenario)

What speed processor are you running?

high and low dma are both set to 1.
my cpu is a pentium mmx 166mhz.

will check the states of the solder joints.

High and low dma cannot both be 1.

Traditionally, low dma is 0 or 1, high dma is 3, 5, or 7.

Yeah, if you have both high and low dma set the same and you try to run a game that utilizes both, you could get the problems you're describing. That might also be why the problem only appears sometimes.

jh80 wrote on Yesterday, 00:29:

Yeah, if you have both high and low dma set the same and you try to run a game that utilizes both, you could get the problems you're describing. That might also be why the problem only appears sometimes.

Based on findings for the PicoGUS which uses the same DMA for low and high, it works for pretty much every game without issues and is a valid configuration - Also used officially with the Vibra 16XV. It's also recommended for other SB16 cards if you have an unstable 16-bit DMA controller.

NeoG_ wrote on Yesterday, 00:33:

jh80 wrote on Yesterday, 00:29:

Yeah, if you have both high and low dma set the same and you try to run a game that utilizes both, you could get the problems you're describing. That might also be why the problem only appears sometimes.

Based on findings for the PicoGUS which uses the same DMA for low and high, it works for pretty much every game without issues and is a valid configuration - Also used officially with the Vibra 16XV. It's also recommended for other SB16 cards if you have an unstable 16-bit DMA controller.

As I recall, I had a problem with the patch for Crusader: No Remorse that improves SB16 support when I had DMA high and low set the same. That manifested as static-y sound possibly like the OP is describing. Using high DMA fixed the problem. There are probably more instances like that, but perhaps they are very rare, in which case it seems unlikely the OP is encountering them that often.

I have a similar problem with a 2230... OPL is good, but absolutely no digitized sounds. Swapped with another 2230, works fine. The 'bad' card is recognized and init properly by unisound and Creative tools. I can see the wave levels responding when I play a sound in Windows too.

Is this possibly a bad op amp?

drosse1meyer wrote on Today, 16:16:

I have a similar problem with a 2230... OPL is good, but absolutely no digitized sounds. Swapped with another 2230, works fine. The 'bad' card is recognized and init properly by unisound and Creative tools. I can see the wave levels responding when I play a sound in Windows too.

Is this possibly a bad op amp?

I think on the 2230 the amplifier chip (Usually a TEA or UTC 2025 chip) is not used for mixing the digital channels, but to set the volume levels for the two stereo channels before the output after already mixing with the OPL sounds, so if that would cause the issue then most likely OPL would be affected too. If the wave level meter in Windows responds properly to digitized sounds then I would consider the most likely chips to affect it to be the ADC/DAC chip(Unfortunately a lot of different types were used on the CT2230 based on availability, so I cannot say an exact chip label) or the CT1745A stereo mixer. These are only the most likely causes, a lot of thing can go wrong with a Sound Blaster 16, also if haven't already check for bulging/leaking caps on the card, those can cause weird issues, however a complete loss of digitized sounds would be unusual.