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I have a Ampeg BA115 bass amp. The unit blows the 2.5 amp fuse as soon as it is turned on. I have isolated the step down transformer from the solid state board and the fuse does't blow. So I know the power transformer is OK. What should I check next, and could you recommend a good repair service.

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6 Suggested Answers

  • 4234 Answers

SOURCE: PEAVEY TRANSTUBE AUDITION 110. PLUG

There should be an 8 pin IC close to the input jack that will be marked 4558 or 4560. This is an Op-amp Ic that is the most likely cause of the problem. Replace that IC and report the results here.
Dan

Posted on May 28, 2008

robotek
  • 1512 Answers

SOURCE: Older Peavey PA Head XR600C.

If you need a circuit for the PA board... get it from here

I would start by checking with a multimeter for shorts in driver transistors Q2 and 12

The output stage may be suspect for a driver to have failed. I would disconnect(emmitter and collector) of each output transistor for leakage and shorts in all directions (swap meter leads +ve and -ve). You can often tell at a glance that there IS a short in the output stage, by checking collector emitter with everything still connected. You cannot, however tell if there is leakage that may kill any repair work that you are doing.

Good work on the lamp. I use one in line with the mains socket on my test bench. I use a 40 watt build though.Have seen some smoke with higher wattages. I also use a variac to soft start the unit and do some DC checks mostly for symmetry in output stages with about 40-70 v into the 240 volt mains socket.

Let me know if you find any shorted transpistanators :)

regards
robotek

Posted on Jun 13, 2008

  • 1 Answer

SOURCE: sony str-de845 Powers up, relay clicks, fuses BLOW!

Buy a slow blow fuse from Radio Shack

Posted on Mar 05, 2009

  • 3 Answers

SOURCE: amp. doesn't turn on

22nf 630dc/300ac capacitor inside back left board, i found mine on top of this board, a magnifine glass will help to check the writing on capacitor, replaced mine, works as new, g.knight. uk. ( rs components.)

Posted on Oct 04, 2009

  • 586 Answers

SOURCE: sony str-da50es. Does not power when power button is pushed.

Hi,
This problem is very common in this model the solution is to replace the fuse with improved one 10A 125V of type CES710A having part No.1-576-695-11. Remember that this fuse would be larger in size of earlier one so that you have to drill it first in the holder and adjust the fuse to a proper space of 1.4 drill bit.
Do the changes and your product work fine.
Thanks.

Posted on Nov 24, 2009

dunnbiker
  • 8546 Answers

SOURCE: Yamaha Amp RX-V1700B Receiver - no power to head unit

Go to the shop.

Posted on May 28, 2010

Testimonial: "Thanks - I came to the same conclusion myself - hopefully something simple and not too expensive."

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Hi phopkins3

You gotta love JBL bottom end:) Is this a new problem or something you have been putting up with. Check settings on the amp first. If you have excessive bass boost you may get this sort of problem. Acoustic isolation is what fixes it. IF bass frequencies are able to couple up to the turn table enough to bounce the needle, then you need to get the T/T better isolated from the speakers. Check that the body of the turntable is isolated from everything, and that it is sitting squarely on its feet. You could also use a rumble filter if your amp has one fitted. The setup on the turntable is also worth a look. Set tracking force to 2-3 grams. Check these things and report back to me here and we shall get to the bottom of your problem for you. :)

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