My 1176 needs your help

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bubbi

Well-known member
Joined
Oct 14, 2011
Messages
61
Location
Iceland
Hey guys,
I have a Universal Audio 1176LN reissue from 2000. All of a sudden it started acting very strange.
It works perfectly for like 10 seconds after I turn it on but then the signal starts to mix with noise and distortion and after around 30 seconds I get no signal and only noise.
I'm thinking it might be a problem with the power supply section but I wanted to check with you guys before I did anything.
Has any of you had a similar problem? Or maybe you just have a good recommendation?

Thanks,
Bubbi
 
OK, so I went to the studio yesterday armed with a meter and it seems to me that the power supply is working fine.

However I noticed that when you turn the unit on a big metal case transistor in the middle of the board gets REALLY hot. It has a heatsink but it's still so hot that you can barely touch it. Could that be a part of the problem?

-B
 
Could be the voltage regulator needs to be changed out-

Could be that transistor needs switched out...If its connected to a heatsink, it should be getting hot...

I take it from your previous posts that this is an orignal UA model and not a hairball model 1176...yes/no ?
 
Yes it is an original UA model.
Does anyone know what transistor this is? It's name has been scraped off on my unit

-B
 
Download the Schematics first.....Google is your friend  ;).......but  it should be  2N3053. The are getting really hot could be normal.
 
First thing in the manual/troubleshooting: If noise and strange behavior develops, clean area around FET transistors. Very often does the job.

Jakob E.
 
I had the exact same problem. It was the Stud Zener, not regulating correctly, the output transistor overheats and hence distortion. Let the unit cool, then it works for 30 secs.

http://www.studioelectronics.biz/sunshop/index.php?l=product_detail&p=1148

 
Thanks sintech, I have ordered the zener, hopefully it will work !
My unit works after cooldown but then starts distorting again so I'm hopeful that changing the diode will solve the problem.

Again, thanks !

-B
 

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