Marshall AVT100 Schematic

[jdg6614]

Purchased a used AVT100 and it would drop-out after a few minutes, now it blows the main fuse as soon as it is turned on. Any schematics available for this amp? Any other suggestions? I'll take it to a dealer if I have to but I think I can figure it out if I have the proper schematic. I've contacted Marshall UK but haven't heard back from them.
Thanks in advance!
P.S. Is a Eminence Beta (8ohm / 250watt) acceptable as a replacement speaker for this amp?

[pecorporation]

[ATTACH]8069[/ATTACH]

[ATTACH]8070[/ATTACH]

[ATTACH]8071[/ATTACH]

[ATTACH]8072[/ATTACH]

[ATTACH]8073[/ATTACH]

[Jazz P Bass]

Marshall AVT100

Sounds like the output ICs are blown.
There is a header that goes to the chips at the fan.
Disconnect it & see if the fuse holds.
Use the search function up top.
Search Marshall AVT100.

[jdg6614]

AVT100

Sounds like the output ICs are blown.
There is a header that goes to the chips at the fan.
Disconnect it & see if the fuse holds.
Use the search function up top.
Search Marshall AVT100.

Thanks to Jazz P Bass and Peabody! Unplugged the IC and it works perfectly through the headphone output. I appreciate the schematicsalso! The previous owner said that the sound level would drop off after playing at moderate to high volume for a while. Could this be related to a faulty IC that finally went out or should I look elsewhere (12ax7)?
I can only test through the headphone output for now as the previous owner removed the original speaker to puy in another cabinet. I have an Eminence Beta speaker orderedfor now, I didn't want to spend too much for a speaker only to find out that I need major work on the circuit board. A better speaker can come later if I want to upgrade.
By the way, will any TDA7293 (or equivelant) work or do I need to go through Marshall for an exact replacement?
Thanks again, Jeff

[booj]

There is only one kind of TDA7293 that I'm aware of, made by ST, available through Mouser P/N 511-TDA7293V
It does come in two forms, the "V" version which is used by Marshall and the "HS" version which has a different pin layout.

[jdg6614]

TDA7293

Hey,Booj!
Thanks for the info. Thanks to other members, I was able to identify my problem. I'm not really a tech, but I know my way around a meter and a soldering gun! Just wanted to make sure that I didn't order the wrong IC with perhaps the wrong voltage/wattage value. Thanks much to all the members out there! By the way, I'm searching for a used footswitch (pedl-ooo30) for this amp if anybody knows of one available.
Jeff

[booj]

Any standard two button footswitch with a stereo plug should work. The tip goes to one circuit, the ring to another, and the sleeve is grounded. One switch shorts the ring to ground. The other switch shorts the tip to ground.

[jdg6614]

AVT100 footswitch

Hey Booj! thanks for the reply, I'm not sure that a standard footswitch will work with the avt100. My amp has a proprietary 15 pin cable for the footswitch. I have the cable but the previous owner said he left the footswitch at a gig. I've seen the switches listed new for around $75.oo, but just need to save as much money as I can; "Things are tough all over!" The only other outputs I have on this amp (other than the speaker output) are an effects loop and emulated output and a headphone jack.
I was just hoping somebody might have one laying around from an old blown amp or something. If you or anybody else knows how I could build an adapter to convert the 15-pin to some other type footswitch, I would welcome the info.
By the way, I did get an official Marshall schematic for this amp from Marshall HQ's. I listed them on another thread if anybody needs them, I haven't looked at them myself yet, but they came from the horses mouth so I figure they are accurate.
Thanks again, Jeff

[booj]

Sorry. I was looking at an AVT50 scat and thought it would be the same thing.