I acquired a Pro Audio Studio, which sounds almost muted but it is indeed working, I noticed a broken ceramic cap in the op amp lf353 section and it is indeed open circuit. I hope someone here can measure his working cap value so I can fix my card. The cap is C92.
The cap is in the same location on these PAS versions I know of:
650-0060-52a
650-0060-53c
My PAS Studio is 650-0060-52e and C92 is in same place. measures 63.8nF in circuit so probably a 63nF / 0.063uF or close.
Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun
Horun wrote on 2021-01-02, 23:33:My PAS Studio is 650-0060-52e and C92 is in same place. measures 63.8nF in circuit so probably a 63nF / 0.063uF or close.
Thanks a lot for your help, I will report back the results after the replacement.
Madowax wrote on 2021-01-03, 03:10:Horun wrote on 2021-01-02, 23:33:My PAS Studio is 650-0060-52e and C92 is in same place. measures 63.8nF in circuit so probably a 63nF / 0.063uF or close.
Thanks a lot for your help, I will report back the results after the replacement.
No problem. Hope you get it working proper. Great cards when they work as they were designed.
added: Just to make sure best if you confirm I checked the proper one, here is the pics. Red circle is around the one I checked.
Did do a resistance check before the capacitance check and was about 5M ohms left side to ground and 3.3M ohms right side.
Not that it matters but do not like doing in-circuit checks if the resistance is too low like in the K range as it can really screw the readings AFAIK
Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun
Thank you for the help, the PAS has been fixed and it works quite well, I replaced C92 with a 68nf ceramic cap, there were also a scorched tantalum cap and a 74hc4316 not working properly, replaced both and now the card is working again and the volumes are well balanced. Tested both the pas section and the thunderboard section with doom, hexen and monkey island. No problems at all.
Beautiful work.
Cheers,
Great Northern aka Canada.
