OK..I'm stumped..Startup

[stevek66]

Well....I finished up my express this morning.Used the lightbulb limiter.
Throw the switch and bulb flashes and dims to a light glow.aok.
Bias range w/limiter -21.00 to -32.00.I guess thats alright.
I only get about 3.0 VAC or so on heaters.
Without tubes I'm getting about 366 VDC
On b+3,b+4 and b+5 I'm getting like .072 VDC..???
I'll post pics later..Something is screwed up..

Steve

[gearhead]

Heaters - is that one feed to ground, or between both heater feeds?

Where is the 366VDC measured?

Are you measuring the B+3, +4, +5 with or without the tubes and with it in on or standby?

[stevek66]

Heaters - is that one feed to ground, or between both heater feeds?

Where is the 366VDC measured?

Are you measuring the B+3, +4, +5 with or without the tubes and with it in on or standby?

Hey gearhead,
I'm getting 366 vdc at pin 6 of v4 and v5 also at standby switch
I'm taking heater readings at pin 2 and 7 of V5
This is all without tubes
Thanks Steve

[Firestorm]

What PT are you using? Did you accidentally hook up the center tap of the heater winding as one of your leads? That would give you half voltage on the heaters.

Without tubes, the 366VDC might be right. Of more concern is the .072VDC on B+3 - B+5. Sounds like you're missing a connection somewhere in the B+ dropping resistor string.

What's your screen voltage?

[stevek66]

What PT are you using? Did you accidentally hook up the center tap of the heater winding as one of your leads? That would give you half voltage on the heaters.

Without tubes, the 366VDC might be right. Of more concern is the .072VDC on B+3 - B+5. Sounds like you're missing a connection somewhere in the B+ dropping resistor string.

What's your screen voltage?

Hey,
Yes I just found an unsoldered wire on one of the 9.1k's
So now at B3 thru b5 I have about 366 VDC
I'm using Mooses trannies.
I have the PT wired
2 yellows @ power board
yellow/red and brown/white to ground
2 browns to pin 2 and 7 at V5

My screen voltage at pin 4 of V5 is -32.56

Does all that look right?

Hey thanks for any help you can offer,I been at this all day.
Played hooky today

Thanks Steve

[doctord02]

What voltage do you read directly off the rectifier diodes junction? You should be seeing above 400, maybe 425 there with the other probe grounded to the chassis.

What is your wall AC voltage?

What did you do with the extra taps for the 260V mains and the 5v tube recto taps?

[stevek66]

What voltage do you read directly off the rectifier diodes junction? You should be seeing above 400, maybe 425 there with the other probe grounded to the chassis.

What is your wall AC voltage?

What did you do with the extra taps for the 260V mains and the 5v tube recto taps?

hello,
W/Tubes in and on Standby,no limiter I'm getting 403 VDC at Diode junction.
wall voltage is 121
and the extra taps were cut short and heat shrinked and are under power board.
Heater voltage is still 3.74 acv at heater wires V5 pin 2 and 7.
Maybe ground..??? Bias is low as well maybe -20
I through the standby switch and plugged in guitar and it sounds decent.
Any ideas and Help are much apreciated

Thanks to all for responding.Now If I can get the heater voltage corrected and bias I should be good to go.

Thanks Steve

[Ron Worley]

Steve-

If you're still on the limiter, this is normal- I had the same deal going and was stumped... all voltages read low with it.

Take the plunge- take the limiter out of the setup and I bet that you are in the right ballpark. I think that I put this in my build guide as well, can't remember....

Ron

[stevek66]

Steve-

If you're still on the limiter, this is normal- I had the same deal going and was stumped... all voltages read low with it.

Take the plunge- take the limiter out of the setup and I bet that you are in the right ballpark. I think that I put this in my build guide as well, can't remember....

Ron

Hey Ron,
I wish it was,but this is without limiter in voltage line.
I'm going to check the Yell/Red and Brown/white to ground and then I don't know.I've been beating my head against the wall allday.

Thanks Steve

[stevek66]

Steve-

If you're still on the limiter, this is normal- I had the same deal going and was stumped... all voltages read low with it.

Take the plunge- take the limiter out of the setup and I bet that you are in the right ballpark. I think that I put this in my build guide as well, can't remember....

Ron

Hey Ron,
I wish it was,but this is without limiter in voltage line.
I'm going to check the Yell/Red and Brown/white to ground and then I don't know.I've been beating my head against the wall allday.

Thanks Steve

[stevek66]

Using my GT bias plug I was able to Bias tubes at 40.
However heater voltage still 3.74 Vac.

[doctord02]

Remember the heater voltage is AC and not DC. Make sure the meter is set correctly... and dont feel silly if thats the case, it's bit me before too.

Fingers crossed...

EDIT - see you posted... dont know what to suggest then, but it seems like it's about half what it should be...

[stevek66]

Remember the heater voltage is AC and not DC. Make sure the meter is set correctly... and dont feel silly if thats the case, it's bit me before too.

Fingers crossed...

EDIT - see you posted... dont know what to suggest then, but it seems like it's about half what it should be...

Hey Doc,
Yes,it is 3.74 ac..Don't get it.

Steve

[doctord02]

Try measuring pin 2 v5 to chassis ground and see if it's the same.

But you get sound, right, and it sounds OK? Or not?

[stevek66]

Try measuring pin 2 v5 to chassis ground and see if it's the same.

But you get sound, right, and it sounds OK? Or not?

Hey Doc,

Both pin 2 and pin 5 of V5 read 3. something Volts ac.
I don't know what it could be.In the morning I'll double check the grounds off the PT and see if thats it.
The amp sounds good though.I just got done playing for about an hour.
It sounds pretty damn good.It doesn't hiss to bad or hum.I'm in a 10 x 10 room with it cranked to about 1 or 2 oclock.
I'm sure it would be even better if it was 100% right though

Thanks Steve