Peavey Max 115 Bass amp

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Hi,

I have a Peavey Max 115 Bass amp that was working fine and it blew the 1.5 amp slow blow fuse in the power supply.

I checked all the diodes, resistors, capacitors in and around that area, no burnt parts, soldering connections are good.

I'm suspecting the power amp IC seeing as this was a used amp that seen some gigs:) All I get is a hum from the amp, the 3amp fuse is good.

I was thinking of replacing the IC OP and the power amp IC as a set seeing as they are linked, and they are cheap enough to buy.

I don't have a schematic for the unit yet, was just wondering if anyone else ran into this problem, there is not much "under the hood" of this amp so it shouldn't be too hard to fix.

I checked the speaker and the voice coil is not locked and it reads 4 ohms with the cables disconnected.

Thanks for any help you give:)
 
Well an update, I traced it down to the Audio amp IC, part number LM3886TF, it was shorted, and other parts in and around the area tested good, I'm replacing the op/amp IC at the same time, cheap insurance, part number CA3080E, was able to get all the parts on Ebay for less then $20.00 and that is doubles, 2 of each IC, back-ups:)

I ordered the parts, when I get them and install them I will let you know how it goes, I can't believe no on on this site has had this trouble before, these audio amp IC's are pretty common at failing, and it is a real common amp IC.
 
problem solved

Hope this helped someone, I know 98% of this site is about building and designing amps but repairing them is important too, I don't design amps just repair them.
Too bad there isn't more of that on here seeing as how big this forum is.
There are common repair issues for most of the popular amps that could be posted and could help others repair their own units by saving money and saving down time at the repair shop.
And I just couldn't imaging packing up a 100 pound amp to be shipped to a repair depot, by the time you got it back after being tossed around what would you have left.
Anyhow just a thought, maybe not such a good thought seeing how little response I received on this thread:)
This repair set me back less then $20.00.
 
ANy product that uses an IC power amp will blow one from time to time, especially in a musical instrument amp, which sees a lot tougher service than home stereo gear. Usually a new power IC is all it takes.

Whenever an amplifier blows fuses, the standard approach is pretty much look for a shorted output device (be it tube, transistor, or power IC), and then look for a shorted rectifier in the power supply, and finally shorted filter caps - in that order. Of course other things could be wrong, but for fuse blows, that covers 99% of it.

This DIY forum concentrates mainly on hifi applications, though there is a musical instruments section here down below. If you want to discuss mostly musical instrument amplifiers, the building and repair thereof, you might also visit www.music-electronics-forum.com. A lot of tube talk over there, but we do discuss solid state as well.
 
Hi to all

What a fabulous forum this still is for all those who have a passion for audio/ music that is why I have re-joined this forum as I am unable to remember my original login details. . I have a small electronics workshop but I also play bass & now have 2 Peavey Max 15 MK2 amps for repair one is mine & one is a friend of a friend. both have the same fault (overheating). U suspect that there is a problem with the output tramsistors but as yeet I don't have a circuit diagram / parts list for these amps.

if anyone could supply me with a circuit diagram or point me in the right direction it would be very greatly appreciated.

many thanks to all

regards

Bassmank
 
Hi Enzo,

Thanks for answering. Yes, I wrote to that email address.

I turn the amp on with no conections but energy. if I wait three minutes or more and then I conect the bass I don't hear anything from the speaker. I turn it off and wait until it cool down and turn it on again and its the same. It only works for three minutes and then the speaker mutes.

I'm from México.
 
Thanks for your comments, nigelwright7557. The speaker is ok, You turn the amp on with your bass conected and it sounds for three minutes, then the speaker mutes. Turn it off and, after a period of time, long enough for cooling down, you turn it on again and you got sound from the speaker for three minutes more and then the speaker mutes again. and so on.
 
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