Sovtek blowing fuses

[Anti-Hero]

Hello

I have just started repairing my own gear, and have a couple of questions

I own a Sovtek Mig-50 Model 001 head, and a few days ago it started blowing fuses, i have been testing everything, and have already replaced the on/off,stand by, and 110/220 selector switch. The filter caps look okay, I am narrowing it down to the PT, or rectifier. Can someone please advise how i can test my PT and rectifier using a DMM? Also other then looking for bubbles how do i test filter caps?

Thank you

[Twist]

Have you tried powering the amp up with the output tubes removed? A good multimeter will have a diode checker.
You may look into getting a setup like I use. I have a variac with an AC current meter. If I suspect an amp has a short somewhere I just slowly power up the amp with the variac and watch for increasing current gain. This way I can back off if the current is rising too high. Also you can begin disconnecting leads from the secondary winding of the PT to isolate the shorted section. If you have disconnected all secondary leads and you still show a short then most likely your power transformer is shorted.
You could use your multimeter to check the DC resistance of each winding of the power tranny. It will show a very low resistance even if it's good on the primary side. An extremely high resistance reading would indicate an open winding. In this case the fuse would not blow, it just simply would not work.

[Anti-Hero]

I forgot to write that i had removed the tubes and tried. I have just moved the pt wires to the rectifier and its still blowing fuses. The filter caps test fine as well as the rectifier is fine. One thing i noticed was that the rectifier only has one diode, is that normal of am i missing some.

Thank

[Twist]

You may be looking at the single diode in the bias voltage supply circuit. Without looking at the amp I don't know if you have a tube rectifier or diodes for the high voltage supply. If you've disconnected all the wires on the power transformer except the primary wires and you're still blowing fuses then your tranny is most likely shorted.

[Anti-Hero]

Its a solid state rectifier