trinityamps.com

Yeah, but since there was more than one tube with the high voltages, I would have bet on bus or ground wire.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

No worries...i understand...

Maybe ill just pop the whole board to try to test the ground bus

You tested from each cathode resistor ground side to ground, correct?

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Yep...what i did was...i have a liitle wire with clamps on both ends...clamped one to the ground probe, the othr to the chasis ground that the bus attaches to...
Then took the lead probe and put it on the turret that goes to ground...
I was getting a reading of 1 or 2...so, to me, i thought it was working, as it showed error when i wasnt touching anything

So unless the component to the turret connection is bad on all of them...or, im not understanding the continuity function...

Didnt have time to look at it today...migraines are a wonderful thing...doubly for musicians...

But did You test from each cathode resistor ground side to ground?

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Sorry..havent posted an update as i havent had time to work on it again...

Will post soon though...i hope

Ok...so...i clipped my jumper cable to the ground bolt and the to the ground probe...

I tested for resistance thru the resistors...theres continuity and resistance...

I tested all the resistors individually but...
1. R29 is supposed to be rated at 470K...only reading about 260K
2. The input resistors (R2&3 and R24&25) are only reading 38K...
3. I have a bleed resistor at C13 to ground that when i try to test...the resistance just climbs...same when i try to test R28

At this point...im not sure what to do...even if one of the caps shorted, how do i test it? And if it is shorted...the circuit would still be grounded since theres resistors beside them

Help this newb out

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Quick edit...
I didnt test the cascade switch or resistors on it thinkin that it shouldnt have anything to do with the voltages

You mentioned early on that there was no tube glow at all? Is this still the case? Have you measured your heater voltage? Set your meter to "AC Volts" and measure from pins 4 to 9 on the LAST tube in the heater chain (V1 assuming you followed the layout) and report back. The heaters are not elevated on this amp so you should get in the neighborhood of 6.3V +/- 10%.

And... this document has brought MANY, MANY amps back to life over the years...

http://www.geofex.com/ampdbug/ampdebug.htm

Have you gone through it yet?

If you haven't, you really really should.

Ok...had a min at lunch today...but before i move forward, heres a question...

With tubes out, i had proper heater voltage to all tubes...now with tubes in, i have the 6.2 across the wires at the tranny, but nothing at the first power tube...if that tube has failed, would it ground out and shunt everything to ground? Would explain why no power after it...

Rectifier is only tube lit...its centre rod glows a nice orange...

Swap the power tubes and measure again. Same result or different?

If it shorted to ground you would (probably) blow a fuse but that is the clue to your problem.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Sorry..as in with a different set...or just rotate the two tubes?

I'll try rotating them and see what happens...

Here is my thought though...after thinking about this a bit...i thought it was the closest tube, shorting everything to ground, then thinking, maybe it was on further down the line, but even then the closest tube would/should have power
Then/now Im thinking that even if the tube had shorted, it would be an internal short and i should still have power before it goes into the tube

I have also thought it was funny that the fuse hasnt blown

Its weird that without tubes the heaters are fine...

Quick update...

I rotated the tubes, but then had a quick look at the heaters...as soon as i put i little pressure on the heater wire soldered to the tag strip it pulled out...so...my guess is, with no load it was working fine, but as soon as a draw was put on it, it was failing...so i re-flowed the solder on the two heaters on the tag board...turned it on and all five tubes lit up...

Due to small house and sleeping kids thats where i stop tonight...even with the VRM its still loud so ill test it out tomorrow, but if all tubes are lit...well..i wont jinx it

Oh man I hope that's it! Keeping my fingers crossed for you!

I was actually thinking that you would have the same result when you swapped the two tubes which would have led me to guide you to checking all your heater solder joints because either the load exposed a cold solder joint or the mechanical act of putting the tubes in broke a connection somewhere in the line. Like stephen said, if it was a shorted tube you should have a blown fuse or burned-up resistor somewhere. If the problem followed the tube then you would know there was a problem with that tube.

I just fixed my bass players Fender Bassman head and it had a shorted tube. It didn't blow any fuses but it did burn-up the 470R screen resistor. When I say burn-up, I mean it literally turned into grey ash when I poked it. I'm glad it didn't cause a fire! New tubes and a new resistor fixed it right up.

Hope that's it, ez!

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

quick lunch time check in..it fired up and is alive again...

grittier than i remember, but it's been down over a month...and maybe its been on its way out for awhile...either way...seems we are back at'r...

will slam'r back in the head shell and get back to rockin...that is...until i decide on modding the normal channel...

thanks for your help all!

Yay!

And you learned something!

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Yep...i dont mean it this way, but it was worth the aggrevation...starting to problem solve...

Now...on to a solid state peavey, that has nothing but a hum...worse when a cable is plugged in

Oh, oh..Time to start a new post - on the Backstgae

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps