AWE32 (CT2760) Diagram to help Recap? \ VOGONS

AWE32 (CT2760) Diagram to help Recap?

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First post, by Glendower

Posted on 2020-01-31, 05:39

Glendower Offline

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Hi all. I used to post a little bit back at Queststudios before my hobbies cycled away from my retro gear. However, the time has come for my interest to swing more fully back to my retroboxes. I bought a PCMIDI card recently and, while waiting for it to arrive from Faroff Lands, I wanted to get things in order for it. I have a CT2760 that I bought new way back when, and I just noticed that the left channel has gone quiet when playing FM and AWE music. Not totally silent yet, but just very quiet. I've done some searching, and all I can see is that people chalk this up to bad caps. That mostly makes sense to me, but since digital audio isn't affected, I say "mostly."

I don't know when this started since I usually use my SW60xg, SCB-55, or MT-32 for music on that machine. Now, what I'm wondering is if there is a diagram available that could tell me which capacitors I ought to replace to fix this specific problem. I'm not great with the soldering iron, but I have swapped out some caps and transistors in receivers before (and in an A4000). I don't fully trust myself to do all of the caps (the risk of failure compounds with every cap!), so it would be nice to know what needs to be swapped. Alternatively, I'd be willing to pay something reasonable to have it done. I know that the card isn't the best and that my other midi devices are better, but it's really just sentimental at this point-- I have other cards I could use for FM.

Also-- while I sort all of this out, would you all recommend that I just pull that card out of the computer? I imagine that I'm risking additional damage...

Thanks!

Reply 1 of 4, by brownk

Posted on 2020-01-31, 07:08

brownk Offline

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I'll just share what I went through while fixing two AWE32s.

- AFAIK, there isn't a detailed PCB diagram readily available on the net. At least, I haven't seen one. I suppose it's b/c creative products back then were mainly produced in Singapore, and factories there were not that leaky. I guess the only way to go for is to read off from actual caps to replace.

- Creative used mostly United Chemi-Con's SRG series on AWE32. Mouser/Digikey/Arrow still sell most of them. Some of them, however, could be out of stock, and when it happens, their leadtime usually stretch to a couple of months. I've opted to use Kemet caps instead as they are dead on match to that of UCC except in one or two minor properties. (I thought about deploying Nichicon's audio-grade golden caps but came to a solid conclusion that it would be massive waste of good capacitors.)

- Some caps are deeply trenched in "plated through-holes". You could easily damage solder-mask and leave a nasty trail if you iron cap holes persistently in hot temp. Low-melt solder makes things only worse. The best way I found is to nudge caps to left & right (or up & down) until cut them loose from the front. Then clean their holes. Easy, clean, no damage.

Godspeed.

Reply 2 of 4, by dr.wily

Posted on 2024-01-20, 11:53

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I'am in too ! My CT2760 start to have it's left channel being too quiet.

When I record a midi tune to wave I have an imbalance between L and R and I must compensate with manual balance on audio mixer.

I notice this is a common issue on SB16 card. I have another a SB16 (CT2230) who has the same issue, but here left channel is just inaudible. Could this be due to stereo amplifier TEA2025b or caps or both ?

Last edited by dr.wily on 2024-01-20, 13:55. Edited 1 time in total.

Reply 3 of 4, by mkarcher

Posted on 2024-01-20, 13:43

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dr.wily wrote on 2024-01-20, 11:53:

I'am in too ! My CT2760 start to have it's left channel being too quiet.
I have another a SB16 (CT2230) who has the same issue, but here left channel is just inaudible. Could this be due to stereo amplifier TEA2025b or caps or both ?

As far as I understand the SB16 architecture, the TEA2025B power amplifier is only used for speaker out. The internal recording of "what-U-hear" and the line output are not affected if this amplifier fails.

Reply 4 of 4, by dr.wily

Posted on 2024-01-20, 14:01

dr.wily Offline

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mkarcher wrote on 2024-01-20, 13:43:
The internal recording of "what-U-hear" and the line output are not affected if this amplifier fails.

I have the imbalance issue through line out and internal recording (but not from digital sp/dif out). Then it's not this chip. Maybe capacitors ?

EDIT : Changed all
- 16v 470µf
- 16v 47µf
- 16v 100µf
- 16v 10µf

No change.

I didn't have any 50cv4.7µf and 50v 1µf. I didn't change those capacitors yet.

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