On follow up there seems to be no filament voltage on the PI tube,all others seem appropriate.

Gentlemen, I have another uncooperative Marshall on the bench,and without a schematic I am lost. There is no output on any channel or power setting,and no pop thru the speaker when checking B+ at tube pins. There is B+ which rises a bit when switching from low to high power,other than that I don't k...

It LIVES !!! Thank you so much for all your help ! Turns out there was a break in the trace from one of the filter caps. Pardon me while I pat myself on the back,but the truth is I never would have solved this one without your help, I am forever in your debt !

Assuming you mean DB2 (as my board reads DB1 and DB2) Reading to ground on DC scale;
+ = 520v
- = 0v
other two leads are 250v each

I understand busy so no worries,and thank you for all your help so far ! I get 29vdc on one side and 25vdc on the other side....this can't possibly be correct.

Black to ground = 174
White to ground = 193
Yellow to ground = 193
Black to white = 369
Black to yellow = 369
White to yellow = 18 volts A.C.

I have a pic,but not sure I can get it to post. I did however observe polarity when installing them,when viewed from rear of chassis the one closest to the filters has the + facing rearward and the next one to the right has the + facing front of chassis as per polarity markings on board. 16698366444...

Per your instructions there is about 23VDC on pin 3 of each of the four power rube sockets, this reading falls to about 9VDC after a minute or two.

Per your instructions it starts out at about 23vdc and goes down to 9vdc after a minute or two. I am bewildered...

Originalky the mains fuse was blowing,this was cured by replacing WO08 rectifier (one was shorted so I changed both DB1 and DB2,problem solved. Info online said remove output fail fuses on rear panel and LEDs should light,they do not.

I'm sorry but I posted in two different spots on here, I read if I remove the two fuses on back panel and their respective LEDs don't illuminate there is issue with the B+. And they do not light up when I do this. Also, what area would I look at because the 3 control lights on front panel no longer ...

Gentlemen, I am trying to resurrect a purple 6100 that came to me blowing the mains fuse. Found direct short in one of the WO08 rectifiers and replaced both,powered up and control lights sequenced. Next I installed power tubes and discovered there was no B+ by making some measurements while powered ...

Trouble with blowing fuses,and replaced the WOO8 rectifiers, solved that issue. After trying to power up the amp, the control lights sequenced on. So after 2 tries, they don't come on anymore and there's no B+ So, I intend to try the filter caps next, but where do I look for the power to the control...