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I have a Cary SLA-70 Signature which I cannot get any sound out of. I've removed the tube fuse to check the bias current, but get no reading at all. I've tested and changed out all the tubes and fuses, but still no sound. I've removed the bottom cover and inspected the caps & resistors and all seems to look good. I've removed all the tubes, then checked the resistors and they seemed to be in spec.
The one strange thing that I noticed was that when I turned the amp off about 20-30 seconds later I would get sound out of the speakers for about 5-10 seconds then it would fade out.
Anyone know what to do next to get this amp functional? Any help is appreciated. Thanks!
Follow Ups:
A big thanks to Michael Samra who talked me through this obscure problem. I appreciate the time you took to help me find the bad standby switch and then find the patchy bias pot. Its a real treat to have my amp back in service without having to spend a couple hundred bucks for service work, not having an amp for a couple weeks, and not having to pack it up & ship it out. Thanks for sparing me from the pain of doing all that! Your help is very deeply appreciated.
Larry,Glad the solution was not too vexing and that it is up and running again.
Best,
The things to replace are the diodes and check to make sure that you do not have an open power supply resistor or choke, or a shorted power supply electrolytic cap. This is all pretty easy to do if you have a volt meter. If you do not do the work yourself, the fix could be expensive.If you are looking to sell, drop me an e-mail.
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Long Live Dr.Gizmo
sell. now.
Doesn't seem like good advice since its not worth as much if it doesn't work. I asked for help, not opinions.
Contact/call Cary - they are helpful.
I forgot to mention that all the tubes light up when the amp is turned on and it appears to be functioning, yeah, except for that dead silence.
Check and see if you have plate voltage on your output tubes at pin 3.As I recall the sla-70 may have a relay in that hv circuit and if thats the case it may not be energizing and that can be caused from a bad relay itself ot the 24vdc source that engerizes it.It doesnt have to be a 24vdc source but thats the place I would look first is 3.Do you have a voltmeter?
Yes, I have a volt meter. I will check it and get back to you. Thanks.
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