Fried Marshall MG100HDFX! PLEASE HELP!!!

[defaced]

Any computer store that sells computer CPUs will have the white goop or better stuff (Arctic Silver 5). It's called thermal grease in those circles.

[Mars Amp Repair]

Well,
I believe if they charge you retail, it will be closer to $40.00 for that pcb w/IC...still not too bad if you haven't got the facility for dealing with double-clad pcb's. glen

[gondogn]

That may be true and please don't take this the wrong way, but I just bought this board from a music store who is an authorized dealer for marshall and was quoted 19.44 so I doubt I'll be buying it from another retailer thats saying it's double. Would you? Now if it was out of stock and that was the only place to get it in a pinch then yes that would be a great deal. I am not an amp repairman nor do I claim to have years of expertise on any of this but when I see a square hole I put a square back into it. Thanks glen for adding another option for the people in your area.

[Enzo]

I'll be darned, the latest price sheet does list them at $19.44, $9.72 dealer cost, the ones for the MG100 anyway. The same 7293 chip on a little board comes in several different types, the only differences being the connector layout, and most of them cost dealers almost $20.

[Mars Amp Repair]

no offence taken.
Yep Enzo, I just ordered a couple for that amp & was also shocked (pleased) to find the cost so cheap...g

[Enzo]

I don't consider $20 cheap where a $6 chip is the fix, but it is better than twice the amount.

[rubymaster92]

ya, that 7293 chip was only 6.50 ordered from digikey, but shipping is a butch. after shipping the total cost came out to 26.63!!! I almost doo-dooed meself. but hey its my amp and its worth it. all i gotts to do now to fix it is get a soldering iron and some o dat thermal white goop.

[rubymaster92]

well the soldering iron shpeal got screwed up but i think i am just going to order the whole board thingy from the marshall dealer. if someone could tell me which dealer was the cheapest i would appreciate it. thanks

[chazlupa]

Same Problem

I'm having the same issue and would prefer to locate and purchase one of the daughter boards(?) with the IC Chip on it?

I haven't seen anything on line, and the local shops I have called want to charge me an arm and a leg to fix. In other words, they won't order the PCB with the IC without getting to charge me for the bench fee.

Any suggestions?

Thanks

Chazulpa

[Enzo]

Try Parts is PArts at:

http://www.marshallparts.com/

[rubymaster92]

i checked that site, but there's nothing there that has anything to do with the IC board. This whole thing is drivin me nuts! Because I am sick of havin to use my Peavey which i have to punch every five minutes because it wiggs out from bad soldering connections which have been fixed like five thousand times!!!

[Enzo]

The point was to contact them and ask for the part you need. They don't list every part in their inventory online. I did look in their parts list for the Marshall MG100HDFX and they show the 7293 IC at least, but you could ask them if they have the whole little power module board and all.

[quazcha]

TDA7293 replacement

cutoff the legs close to the pcb remove the IC and them unsolder the legs with solder braid, install the new IC,apply white heatsink compound and re-attach to the heatsink watch the resistance from the IC tab to ground it should mw\easure in the Meg Ohm range if not re set the Ic to the heatsink

[Mars Amp Repair]

TDA7293 protection diodes.

One interesting addition to the saga of the exploding TDA7293's is Line 6's addition to prevent catastrophic failure of these IC's.

They are suggesting adding super fast switching diodes from the output to the rails much like they started to do with the tube amps.

The number diode they suggest is STTH2R02. I'm sure any fast acting high amperage diode would do the trick.

You just put them in a reverse biased fashion from the + rail and the - rail to the output pins on all the power IC's in the amp.

I hesitated to try these on the MF350 (Mode Four) Marshall as they use the four IC's in weird arrangement, but I think they'd be fine on any other dual IC arrangement. I'll have to do further investigation on the MF350.
Just an FYI if you want to go that one step further for the cust.

glen

[Enzo]

I hesitate to even TOUCH an MF350.