Marshall plexi reissue bad power trans possible

[stevesamps]

I have a marshall reissue plexi on the bench blows the mains fuse all to hell
very quickly , is there any history of bad or weak power transformers in this
model? its funny the power trans acually says 39.99 on it and its a drake

I do have an MPT50 around so before I smoke to many more fuses
anyone can think of anything else to check?

I was also going to try and disconnect the secondary from the diodes to
see for sure if its on the primary side..

Steve

[Enzo]

Before you go swapping trannys, please DO disconnect the secondaries. If the transformer blows fuses with its secondary wires all disconnected, then it is probably bad. But a shorted rectifier on the high voltage, or a dead short across the heater winding will blow mains fuses instantly. SO can a bad output transformer or even power tube. Of the mains fuse blows even with standby switch OFF, then the last two items are not likely the problem.

[stevesamps]

Thanks Enzo...
always the voice of reason!

Yes its an awful big transformer to have died nothing looks burnt either..

I will definitely disconnect the secondaries and trouble shoot some more

Steve

[R.G.]

I have a marshall reissue plexi on the bench blows the mains fuse all to hell
very quickly , is there any history of bad or weak power transformers in this
model? its funny the power trans acually says 39.99 on it and its a drake

I do have an MPT50 around so before I smoke to many more fuses
anyone can think of anything else to check?

I was also going to try and disconnect the secondary from the diodes to
see for sure if its on the primary side..
Steve

Better yet, go read the tube amp debugging page at geofex.com.