No thoughts other than that I have exactly same symptoms on my CT1750 MCD, so I'll be watching this thread in case a solution presents itself. I'm no huge SB16 fan and I have enough of them to be willing to try something like desoldering the TEA2025B - I might even have a spare knocking around somewhere...

You can try swapping the TEA2025B, it's not entirely implausible for them to go bad. You can probably scrap some off cheap clone sound cards (just don't waste a card that's actually better than an SB16).
Also, dumb question, but you made sure the RSPK_EN jumper is set (closed), right? (If applicable)

Eep386 wrote on 2021-02-26, 04:31:

You can try swapping the TEA2025B, it's not entirely implausible for them to go bad. You can probably scrap some off cheap clone sound cards (just don't waste a card that's actually better than an SB16).
Also, dumb question, but you made sure the RSPK_EN jumper is set (closed), right? (If applicable)

Yeah its closed. I just ordered 25 pcs of the 2025B , Malaysia branded from Hungary , might take a few weeks . I will be decapping everything and replacing all the caps.

Too risky to just remove the 2025b with caps all around it .. Would rather use light heat with soldering iron to remove the pins and pry it out gently. Using my hakko desoldering iron puts alot of stress on the pads

May also invest in some good caps , however chinese caps will do the job just fine. Not like I will keep this card more than 20 years, however may increase the resale value

Can't find my spare TEA2025B, so ordered two online. I don't have an official desoldering iron, but am confident I can get the pins free with my Ersa iron and a separate sucker.

dionb wrote on 2021-02-26, 13:46:

Can't find my spare TEA2025B, so ordered two online. I don't have an official desoldering iron, but am confident I can get the pins free with my Ersa iron and a separate sucker.

Just bought some gold audio grade caps.. got everything desoldered. Might be a week before I can get the parts. Should only take me 1 hour to get everything back on.

I actually will be doing two cards .. I have a feeling it should fix the mono output back to stereo .

Forgot to mention you will need a good desoldering iron for the 2025b the solder is super old and even reflowing it , my manual pump did not work.

The second card I will be removing all the caps first, then reflowing the 2025b with new solder on the back , then put on flux and using my head gun to gently remove the 2025b . Already ruined one pad but will be using my continunity tester to make sure the pad i put back is connected to the trace line with continuity.

Will snap some photos after I clean the board without the caps and 2025b . I use branson E cleaner with my ultrasonic and card comes out new in 5 min

I must say it sounds amazing now
New 2025b
Gold nichion audio caps

and fixed my issues with the card

dionb wrote on 2021-02-26, 13:46:

Can't find my spare TEA2025B, so ordered two online. I don't have an official desoldering iron, but am confident I can get the pins free with my Ersa iron and a separate sucker.

You will need a desoldering gun to remove the solder quickly after caps are gone and the removal of the 2025b

I can remove the old caps though with my soldering iron 5x quicker

I own 4 of these 4.05v and will be redoing them all , as well as my 3 CT1600

Must have good speakers to appreciate the quality. Using Logitech Z623 speakers and sub
Sound Blaster PRO is muffled lacks fine detail/volume

Ultima VI with MT-32/CT1740 gold nichion recap
https://youtu.be/VVmdwf9AMyk

Wing Commander
MT -32 Sound Blaster PRO CT1600 no recap
https://youtu.be/cysJzcOzbwE

Wing Commander
MT-32 Sound Blaster CT1740 Recap gold nichion
https://youtu.be/rVSer3caOxo

Unrealcpu wrote on 2021-03-22, 04:38:

dionb wrote on 2021-02-26, 13:46:

Can't find my spare TEA2025B, so ordered two online. I don't have an official desoldering iron, but am confident I can get the pins free with my Ersa iron and a separate sucker.

You will need a desoldering gun to remove the solder quickly after caps are gone and the removal of the 2025b

I've done worse (Dallas RTCs) with just the iron and sucker. Not fun, but on old non-ROHS solder I'm confident I can do it without damaging the rest.

My TEA2025Bs have arrived, all I need now is some time to mess around with them.

I can remove the old caps though with my soldering iron 5x quicker

I own 4 of these 4.05v and will be redoing them all , as well as my 3 CT1600

I'll mess around with the CT1750, if that works I also have an ALS007 card with similar issues (weak, mono output) and a TEA2025B

dionb wrote on 2021-03-22, 08:41:

I've done worse (Dallas RTCs) with just the iron and sucker. Not fun, but on old non-ROHS solder I'm confident I can do it witho […]
Show full quote

Unrealcpu wrote on 2021-03-22, 04:38:

dionb wrote on 2021-02-26, 13:46:

Can't find my spare TEA2025B, so ordered two online. I don't have an official desoldering iron, but am confident I can get the pins free with my Ersa iron and a separate sucker.

You will need a desoldering gun to remove the solder quickly after caps are gone and the removal of the 2025b

I've done worse (Dallas RTCs) with just the iron and sucker. Not fun, but on old non-ROHS solder I'm confident I can do it without damaging the rest.

My TEA2025Bs have arrived, all I need now is some time to mess around with them.

I can remove the old caps though with my soldering iron 5x quicker

I own 4 of these 4.05v and will be redoing them all , as well as my 3 CT1600

I'll mess around with the CT1750, if that works I also have an ALS007 card with similar issues (weak, mono output) and a TEA2025B

I have a few issues that I need help with .

When connecting my speaker wire from the sound card to the motherboard I get feed back and can barely hear the pc speaker sounds through my stereo speakers. It does this o n my other CT1740s as well , so not sure what I am doing wrong since the drivers are installed and sb16set program was used to set volume. My CT1600 di d not do this

another issue is that this card had general midi support for mt-32 yet will not work on Ultima VI or wing commander.? I am assuming these are intelligent mode games? Soft mpu works but i thought i didnt need to use this program since the mpuu 401 is on the sound card.

Also space quest V hangs and takes forever to boot with soft mpu 401 with mt32 any idea ? I thought 4.05 fw was the best

Unrealcpu wrote on 2021-03-22, 14:30:

[...]

I have a few issues that I need help with .

When connecting my speaker wire from the sound card to the motherboard I get feed back and can barely hear the pc speaker sounds through my stereo speakers. It does this o n my other CT1740s as well , so not sure what I am doing wrong since the drivers are installed and sb16set program was used to set volume. My CT1600 di d not do this

Usually that's something in mixerset not set correctly. Maybe worth posting your mixerset settings.

another issue is that this card had general midi support for mt-32 yet will not work on Ultima VI or wing commander.? I am assuming these are intelligent mode games? Soft mpu works but i thought i didnt need to use this program since the mpuu 401 is on the sound card.

MPU-401 comes in two flavours: basic UART and intelligent mode. These cards support UART only, not intelligent mode. You need SoftMPU for that, so behaviour is as expected. Only MPU-401 itself, successors and clones support intelligent mode. The only sound cards that do are Roland LAPC-I and SCC-I (and the community made Orpheus, if you bought the extended version).

SB16 has UART only with varying levels of bugginess. The 4.05 is the least buggy, with only slowdowns when playing MIDI at the same time as 16b digital audio. You won't notice this on MT-32 games as none use 16b audio.

Also space quest V hangs and takes forever to boot with soft mpu 401 with mt32 any idea ? I thought 4.05 fw was the best

Personally I hated the x-Quest games with a passion, so no recent experience with them. However I'm aware that SQV doesn't require intelligent mode, and that it is speed sensitive, failing to initialize audio hardware on CPUs faster than a ~20MHz 486. You don't say what kind of system you're running, but if it's faster than this you might have to slow it down.

Yes my l1 and 2 cache was disabled