Marshall MKII schematic

[lowell]

anyone know where I can find one? Also, the amp is blowing fuses. L-bulb in series w/ amp glows VERY bright. I just completely recapped the amp and retubed the amp only to find out when I powered it up that the fuse blows. Pulled all tubes - still bright bulb, disconnected all secondaries on p-transformer and still brightly glowing lightbulb. How do I test for a short in the primary? Can this be done? Is the test I performed a sure sign the PT is shot?

[Enzo]

Disconnect the PT primary wires. If your bulb now still blows bright, ther is some short in the chassis wiring or maybe in a cap across the mains. If the bulb stays dim, then the PT was likely bad. At that point connect the primary wires - still disconnected from the amp chassis - directly to your bulb power. If it brights on you, the PT is bad. Follow?

[jrfrond]

If you have ALL of the secondaries disconnected and you are still drawing current, you have a shorted power transformer.

[Enzo]

Unless there is a short in the mains wiring.

[lowell]

ok guys... thanks for help. so i disconnected ALL leads of p-transformer. the light bulb completely stopped glowing at all. i then hardwired the primaries to the bulb with all secondaries disconnected and it glowed brightly. i then disconnected all leads of p-transformer from everything including the bulb, and i plugged the amp in w/ no glowing of bulb. p-transformer's fried then i guess. is there a final measurement i can perform on the transformer w/ it out of the chassis to confirm this? also, where can I get another transformer?

[Enzo]

AT this point the remaining measurement to take is your wallet.

[jrfrond]

AT this point the remaining measurement to take is your wallet.

:) :) :)

[lowell]

funny... yes, but seriously... no really. I looked at Mercury transformers and they have a replacement. What are my options, I'd like to know if there's anything more affordable yet reliable out there.

[jrfrond]

Have never had a problem with the replacements available from CE Distribution, Magic Parts or New Sensor, which are WAY more affordable.

[lowell]

ok exactly what I needed... thanks!