Marshall AVT150H Blowing Fuses

CKuzGuitars · 11-05-2009, 05:35 AM

I know you guys have seen this before. I replaced the fuse with a 4a 125v from radio shack and it blew right away. After some research, I replaced the audio amp ICs on the two small boards. I tried to power it up without a speaker load and it blew the fuse. That was probably a mistake so, I tried it with a speaker load - same result. So, I unplugged the amp boards and used a new fuse and it powered up. The sound from the headphone out was normal.

So, at that point I decided to see if it was one of the chips so, I tried them one at a time. The fuse didn't blow but, it smoked the chip.

I noticed a few things at this point, the amp has been worked on several times and this is not the first time this replacement has been done. also, there was very little paste left under the chips.

Any help?

Chuck

Enzo · 11-05-2009, 07:14 AM

There have been a number of threads here on this amp model. I suggest searching them out, and reading through them. Your questions may have been answered. If not, then we are still here.

11-05-2009, 05:35 AM	#1
CKuzGuitars Junior Member Join Date: Jul 2009 Posts: 1	Marshall AVT150H Blowing Fuses I know you guys have seen this before. I replaced the fuse with a 4a 125v from radio shack and it blew right away. After some research, I replaced the audio amp ICs on the two small boards. I tried to power it up without a speaker load and it blew the fuse. That was probably a mistake so, I tried it with a speaker load - same result. So, I unplugged the amp boards and used a new fuse and it powered up. The sound from the headphone out was normal. So, at that point I decided to see if it was one of the chips so, I tried them one at a time. The fuse didn't blow but, it smoked the chip. I noticed a few things at this point, the amp has been worked on several times and this is not the first time this replacement has been done. also, there was very little paste left under the chips. Any help? Chuck

11-05-2009, 07:14 AM	#2
Enzo Senior Member Join Date: May 2006 Location: Lansing, Michigan, USA Posts: 10,366	There have been a number of threads here on this amp model. I suggest searching them out, and reading through them. Your questions may have been answered. If not, then we are still here. __________________ Education is what you're left with after you have forgotten what you have learned.

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