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Post by crispycircuit on May 5, 2009 2:15:23 GMT -5
Greetings, My Red Compact with 2 tubes quit on me... The bass keys play, but the solo keys (regular keys) stopped playing. I believe I tracked it down to the transistor that amplifies just before the tube output.... it's SFT 352 What is the proper replacement for it  ? On the schematic it's called TN1 ..........and it mounted in the power supply / output chassis. |
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Post by crispycircuit on May 5, 2009 12:59:44 GMT -5
The stock SFT 352 crosses to NTE 102A (Germamium) . I ordered 1 from Newark along with a 9.1 volt 5 watt zener ... I also replaced the old selium rectifiers. I'll keep posting my results as parts arrive..... I really could use a parts list to my Compact.....
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Post by crispycircuit on May 13, 2009 13:01:20 GMT -5
Well, I received the parts quickly from Newark but it didn't fix the problem. I was working without a complete schematic and that just adds to fustration. So I ordered the completed schematic form Mark Glinsky (seller on the web of schematics). Stay tuned for my next guess on this repair.....
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Post by crispycircuit on Jul 12, 2009 22:42:52 GMT -5
Sorry for the delay.... Turns out this is an early Red Compact and the output stage is different. After spending a lot time with the correct schematic it turned out to be T1 (transistor in the output stage) I had wired it wrong. So it's back up and running again. It works great. I'll clean the contacts and tune it up! I ended up using an osiloscope to trace the signal - I learned a lot !...... Cheers....
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Post by crispycircuit on Jul 16, 2009 11:36:49 GMT -5
The 5 watt 9.1 volt zener and the transistor from Neward works great. It's hard to find 5 watt zeners. The transistor was around $6.50 which seems expensive for a little dinky thing. Anyway, the old orignal diodes should be relaced because they get leaky. It would be great if they lasted as long as the originals !!!
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Post by mtwallet on Mar 27, 2011 9:05:53 GMT -5
Greetings, My Red Compact with 2 tubes quit on me... The bass keys play, but the solo keys (regular keys) stopped playing. I believe I tracked it down to the transistor that amplifies just before the tube output.... it's SFT 352 What is the proper replacement for it ? On the schematic it's called TN1 ..........and it mounted in the power supply / output chassis. I got the opposite problem ; black bass keys don't work I replaced all the caps on the bass/vibrato card (the vibrato works well, but there's a +/- for each effect) the transistors are good on it too... I just can't find any solution... so you're saying that the problem of no sound was coming from the preamp...? it you fixed it by changing the transistor, then I suppose the preamp of the regular keys and the bass keys are different, right? would you please let me know more? thanks F. |
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Post by evomaxir on Jul 4, 2019 15:59:49 GMT -5
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Post by buhimox on Oct 23, 2019 7:36:05 GMT -5
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? On the schematic it's called TN1 ..........and it mounted in the power supply / output chassis. 