Ampeg v4 trouble that needs to be shot

[Ampig]

I have an old v4. I just replaced the two prong for a three prong cord. I turn the standby to operate and there is a massive over current when I have the ground hooked to the chassis. So much so that it blows my 15 ampvac breaker. I just replaced the OT with a good one from Fliptops. Thus far, I have checked all of my filter caps and all's wells. My 20/20mfd@450v is showing open lead on my meter but it appears to be taking a charge when on standby. Diode D5 blows to short when chassis is grounded. Other than that I have checked all of the rectifier diodes to be good.
With D5 removed i can safely ground the chassis without blowing the breaker. Where should I be looking for this short to Chassis? Help.
Questions will be answered quickly as my soldering iron is hot and I am taking this day to fix this f**ker!

[Ampig]

Now for an update. With all of my filter caps disconnected and one leg (red/white) lifted from the board. I still have 240 vdc to earth ground from the chassis. Hello? anyone? Gotta get this done

[Amp Kat]

Looking at the schemo it doesn't show diode numbers so I don't know which one is D5. Things that I would suspect dragging the power supply down or the plate resistors on the power tubes and there are also back to back diodes on the OT primaries so check those out. Which diode are you refering to and do you have the tubes out ?

[Ampig]

Diode D5 is the one between ground and the standby switch. All of my diodes are good and have been replaced. I have the input jacks out right now and they are what's hot. With both legs of the PT connected, using a meter. I get 510 vdc from the negative input to earth ground at high amperage. So "somewhere" there is a short to input ground. I have disconnected the reverb board and still have the same problem. It is somewhere either on the main input/power board or the tone control board. I am stumped. Wait, let me check. Nope, still stumped. Perhaps my troubleshooting skills aren't what they used to be. I also have the input jacks isolated with an insulator between the grounding contacts. There is lots of potential on the ground side of the jack. As I said, the filter caps are all disconnected. Yep, I'm still stumped. This will be a hunt and peck mission, I guess.

[Enzo]

OK, the amp used to work. You replaced the mains cord and now it pops the wall breaker when you flip it out of standby. I'd be thinking something you did during the process is bad. As opposed to some component failure. Possibly the wiring is in error, or you might have knocked some other connection loose or left somethings touching.

[Ampig]

OK, the amp used to work. You replaced the mains cord and now it pops the wall breaker when you flip it out of standby. I'd be thinking something you did during the process is bad. As opposed to some component failure. Possibly the wiring is in error, or you might have knocked some other connection loose or left somethings touching.

At this point I have been through the backtracking and to no avail. I have isolated the short to the main or tone board. It is not a diode as they have all been replaced a few times this week now. Grounding the chassis tended to blow diodes. I think that my troubleshooting at this point is in the limited range. Usually I have an easy time and since i am self taught I am having doubts about my ability. I certainly know enough to not get killed and have been successful in the past with repair, but this amp is a PITA!

[Ampig]

Trouble ahs been shot with a little help from my new friend. The issue is that the secondary high voltage is shorted in the PT to the blue legs of the primary. What secondary voltage can I run this amp on? I have 397 vac secondary with the blue and blue/white lifted.