Hi all,
I am going to attempt to fix my son's Marshall amp and need some tips/hints.
The problem apparently started a few minutes after his band practice started. The top head chassis vent was blocked and I'm not sure about anything thing else concerning proper cords etc.
Looking at the heat sink rail, the cooling fans need cleaning. The sink compound used between the amp device and the sink looked discolored/yellow. Both TDA7293's are popped/burn't on the right side. Looking at the rest of the circuitry looks undamaged.
Here is what I plan to do.
Since his band is a metal band and the amp is at 3/4 to full power, I want to install and higher cfm fan to help cool the amps.
Both amps will have to be replaced, I need advice here as both sides of the PCB have tracks. What de-soldering techniques and size iron/solder do you suggest.
To be sure of the cord/speaker load double check the speaker ohms/and cord length and design.
Should I check anything else?? Please be specific as to what and where if you add help here. I don't have a scope, however I do have a digital V/O meter.
Schematics/Manual I'm using:
Manual: http://www.marshallamps.com/download..._275%20hbk.pdf
Scheme: http://music-electronics-forum.com/a...avt150-275.pdf
Many Thanks
Dmos
I am going to attempt to fix my son's Marshall amp and need some tips/hints.
The problem apparently started a few minutes after his band practice started. The top head chassis vent was blocked and I'm not sure about anything thing else concerning proper cords etc.
Looking at the heat sink rail, the cooling fans need cleaning. The sink compound used between the amp device and the sink looked discolored/yellow. Both TDA7293's are popped/burn't on the right side. Looking at the rest of the circuitry looks undamaged.
Here is what I plan to do.
Since his band is a metal band and the amp is at 3/4 to full power, I want to install and higher cfm fan to help cool the amps.
Both amps will have to be replaced, I need advice here as both sides of the PCB have tracks. What de-soldering techniques and size iron/solder do you suggest.
To be sure of the cord/speaker load double check the speaker ohms/and cord length and design.
Should I check anything else?? Please be specific as to what and where if you add help here. I don't have a scope, however I do have a digital V/O meter.
Schematics/Manual I'm using:
Manual: http://www.marshallamps.com/download..._275%20hbk.pdf
Scheme: http://music-electronics-forum.com/a...avt150-275.pdf
Many Thanks
Dmos
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