Peavey Amplifier repair. Model: PV-4C

An owner of a restaurant and a friend of mine brought me a very old amplifier. The main problem with this amplifier is when you power it up, it comes on for a few seconds then it shuts down. I could hear the fan come on but that is about it.

I have seen this kind of problem before and I think I can fix this one. The only problem I am facing with the kind of repair is finding parts for this amplifier. It is old and in my country, it is very hard to find such parts for old equipment.

It was very dirty on the inside and all the parts were covered with dirt. I used a powerful air blower to clean the inside of the amplifier. Now I could see the part numbers on the components inside this equipment.

Usually with this kind of amplifier, when powering the machine and it goes to shut down, it is a problem with the main output power transistors.

In this case, I found three transistors shorted out. The part number is 70483180 NPN transistors. I called almost every story in Bethlehem area to look for these parts but I could not find any. Since I could not locate them in stores, I started calling my repair friends in the city and to my surprise, I found the same brand amplifier, but the guy told me that is was dead, it shuts down after few seconds which is the same exact problem that I facing here. I went to his store and got it for free. I was thinking maybe I could get find three working transistors out of that amplifier.

I opened that machine and I was so lucky to find five working transistors. I replaced three working transistors into my clean nice old amplifier and when powering the machine up, it worked very nicely.

I was actually shocked at the quality of the sound that this machine was producing. I called the customer and he was happy and shocked at the same time that this old machine is alive again. We went back to the restaurant and I installed the amplifier for him. It sounded really great and at the end of job well done, he offered me a nice meal and of course paid for the repair job after I gave him a very good discount.

This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment. Please give a support by clicking  on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments.

By the way if you have any good repair article that you want me to publish in this blog please do contact me HERE.

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9 Comments

1. 

   shihab kably

   June 27, 2013 at 11:52 am

   thanks for sharing this valuable informations

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2. 

   beh

   June 27, 2013 at 3:25 pm

   hi waleed
   i love all old machines and thank you so much you saved this one
   beh

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   • 

     Waleed Rishmawi

     June 29, 2013 at 9:10 pm

     You are Welcome Beh. I am glad you enjoyed the artcile. I love working on old machines too but the main problem is the finding parts for them.
     thanks again.

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3. 

   Amir Mukhtar

   June 27, 2013 at 5:28 pm

   Dear Mr. Waleed
   Thanks you for such a nice sharing in repairing history.Actually, this type of power Audio Amplifiers do provide better output impedence. Any how thanks you . Also, In pakistan usually, many peoples do use these type of Amlifiers because of Low in Cost and manufactured locally with 2N3055 Transistor.

   Thanks you Again for your Experiences Sharing:
   Amir Mukhtar AShrafi
   A Student of Electronics

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   • 

     Waleed Rishmawi

     June 29, 2013 at 9:13 pm

     You are Welcome Amir. Like I told Beh, I love working on old machines but the main problem is finding parts. I am glad you are enjoying the articles. Electronics is fun and when fxing things, it is more fun. have a good day

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4. 

   randy warren

   March 11, 2014 at 12:25 am

   Thanks, Waleed. Peavey makes some pretty solid amps, and are well known in the US for solid and long lasting performance. In the year I worked at Music Tech, we only had one Peavey come in for repairs and it was pretty far gone, when they go, they really go! Just one thing I wanted to mention, you note that you gave a good discount to the owner. I am not the one to tell you how to run your business, but I am somewhat concerned with the value that electronic repair techs are given. Here in the US there are not many techs, people just don't want to pay a fair price to get something repaired, and many tech make their income by fixing abandoned and thrift shop electronics which they then sell on ebay. Some others have found a niche for high value electronics that the owners are willing to pay a fair price to fix. I just worry that we E-techs just under-value our work to the degree that many people think we should work for free, at least that is the impression I get from many customers...

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5. 

   Marulitua Hutabarat

   May 29, 2014 at 7:52 pm

   Hi Waleed,
   Nice article to share..
   Cheers,
   Marulitua Hutabarat

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6. 

   Cesar

   July 31, 2019 at 8:40 am

   Hello Walled , Nice Article, Now I am Repairing one of these peavey model(PV-4C), and one termic device that be on a heat dissipator is broken and i didnt see the part number. Could you give to me that number please ?

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7. 

   Anthony mcdonald

   October 29, 2021 at 11:31 am

   The right breaker tripped I then remove all eight transistors test them all good but when I reinstall them the left side start tripping I did not put them back in order...thanks anthony

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