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Hi All
I hope you and family are safe from the covid thing going around. A friend sold a Marshall DSL401 to someone and it had the typical heater bridge blow out, Im fairly sure. The amp is remote (in Poughkeepsie area) I haven't seen it yet. The amp stopped working, blew a fuse. Long before my friend asked my about the amp, he got a new power transformer, and installed that. I have a feeling that the PT may be good, but that's another story.
The amp blew out the heater fuse. He installed a new PT, new fuse, started up the amp, no sound. This is when my friend asked me about it. I asked him to leave the standby ON (so no sound setting), take photos of all the tubes. Guessing it was the bridge, 3 small tube heaters are off, 1 small tube heater (phase inverter) is ON. I checked the schematic I have and it shows the 2 preamp and tone stack drivers tubes are all fed from the BR102. So, without having probed with a voltmeter, I am guessing this amp had the standard bridge blowout.
Bridge found on Mouser, no problem there. My questions are:
1) what else tends to blow out in these amps? If the amp is early 90's, guessing, then the electrolytics are pushing 30 years old. Should these be checked for Dc leakage?
2) I got photos of the amp, and looks like a REALLY tight fit in there to put a heat sink on top of the bridge. Ive seen videos and photos of techs just installing a new bridge but mounting it 1/2" or 3/4" off the ckt board. Of course, will help with air flow, but still won't get heat off the bridge. These seem to be hard to get, but any use in getting one of these:
https://www.mouser.com/Thermal-Manag...5gfs?P=1yzvkz5
Aavid 6222BG, and grinding part of it off so it will fit in circuit?
I hope you and family are safe from the covid thing going around. A friend sold a Marshall DSL401 to someone and it had the typical heater bridge blow out, Im fairly sure. The amp is remote (in Poughkeepsie area) I haven't seen it yet. The amp stopped working, blew a fuse. Long before my friend asked my about the amp, he got a new power transformer, and installed that. I have a feeling that the PT may be good, but that's another story.
The amp blew out the heater fuse. He installed a new PT, new fuse, started up the amp, no sound. This is when my friend asked me about it. I asked him to leave the standby ON (so no sound setting), take photos of all the tubes. Guessing it was the bridge, 3 small tube heaters are off, 1 small tube heater (phase inverter) is ON. I checked the schematic I have and it shows the 2 preamp and tone stack drivers tubes are all fed from the BR102. So, without having probed with a voltmeter, I am guessing this amp had the standard bridge blowout.
Bridge found on Mouser, no problem there. My questions are:
1) what else tends to blow out in these amps? If the amp is early 90's, guessing, then the electrolytics are pushing 30 years old. Should these be checked for Dc leakage?
2) I got photos of the amp, and looks like a REALLY tight fit in there to put a heat sink on top of the bridge. Ive seen videos and photos of techs just installing a new bridge but mounting it 1/2" or 3/4" off the ckt board. Of course, will help with air flow, but still won't get heat off the bridge. These seem to be hard to get, but any use in getting one of these:
https://www.mouser.com/Thermal-Manag...5gfs?P=1yzvkz5
Aavid 6222BG, and grinding part of it off so it will fit in circuit?
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