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Looking at the board layout, from right to left, beginning with the .68uf cap, the first two are ok, 1.0 & 1.0. But the next few, are about 100 volts high. THey should be 155 and they are reading 255. What does this mean?

I have been getting squealing when I turn up the gain and Im sure this is the reason, but doe any of you guys know what this means and how I can fix it?
Thanks,
Jon

It's like there's no current flowing thru the plate resistors (100k). Are you sure that V1 is OK? It's got a lit filament?

yes, the amp works and it sounds good. But it squeals like mad when I dime the gain on the plexi channel.

V1 is lit and working. I have tried a few tubes and I get the same thing with all tubes

Ok..Can you check the voltage (careful!)at the other end of those 2 100ks, where they connect together on the other side of the board. It's electrically the same as the + end of that big 16uf cap in the center of the board. The voltage there should be 272 vdc. If it's close to that then we're back to V1 not draing current through the load resistors. If it's way higher than 272 then you need to check the B+ then along the buss as it gets dropped by those bigger 2 watt resistors.
Stew

The voltage at both of the points you suggest I test is approximately 492 vdc. Way too high. Im not sure I understand what you mean when you say I should "check the B+ then along the buss as it gets dropped by those bigger 2 watt resistors?" Can you please be a little more specific as to how to do this?

And thanks for your help Stew!!

OK here we go.. The B+ is the high voltage DC right off the rectifier and the firstfilter cap. That's one side of the large can cap you installed near the transformer. There's a 1k5 (1.5K) resistor connected to the other side of the can cap. This drops the voltage some. from there it goes to that 8K2 resistor on the board where it's again filtered by a 16uf cap (adjacent to V4) From there there's a jumper under the board that feeds the 2 100ks for the phase inverter tube, and carries on to one end of a 2.2k resistor that again drops the voltage some and is filtered by that 16uf cap in the center of the board.
So you start off with about 350v of B+ and each time it goes through a resistor it gets dropped a little till you get to the top of the 2 100Ks we already looked at where it should be down to about 272.

Stew

BTW all the voltages we're talking about and what Stephen has on the sheets is with all tubes installed and warmed up. Meter on DC and AC where it should be. AC for filaments and power transformer primary/secondary DC for the rest.
Hmm 492 eh!!?? don't understand how it could get so high! If you check the filament voltage at say..the solder terminal along side of the transformer (with the twisted wires) and get 6.3 volts A.C. then we'll know you have the tranformer primaries wire correctly.
Then make sure the center tap of the secondary is grounded and that can cap is connected properly.
Stew
Better make sure that bare copper ground wire along the board edge is grounded to a lug near the i/p jacks.

UHH dont I feel like the moron. I had my meter set wrong. Numbers are better, but still off. at the big 16uf in the middle of the board its 225 vdc. at the 100k which shares a terminal with the .022uf cap its 121vdc and when I touch the meter probe there I get a big popping/scratchy noise.

Also, the heaters only measure 2.6vac where the two green wires connect to the red/black heater wires at the 5 lug terminal. What is happening here?

You measure across the filament wires to read the voltage ie. one probe on each wire.
Now every thing is low. Hmmm What is the reading on the can cap? This one with one probe on a good chassis connection right!.
The popping noise is normal..and good in this case .
I'll be away from the computer till this PM. If the B+ is far off chec (AC reading) across the 2 red wires on the rectifier tube (pins 1&7) Should be 290Vac. If this is off re-check the 0-120-240 wiring.
Stew

Also, I dont have that 2w gray colored resistor on the can. But its not in the layout I have. Only the square 1k5 2w is on my amp. I only know of the gray one because I saw it on pictures of another build. Is there supposed to be 2 resistors on the cap can?

ok, the heaters are 5.6 with one probe on each terminal, and the can is 306 vdc on one terminal and 283 vdc on the other.

accross the 2 red wires on the recto it reads 555 vac. i will check the trans wiring

I think I see it. Off the pt, I grounded the green/ yellow wire because I went off photos I saw on this site. I think those may have been pics of a European build. Im in North America.

Can anybody tell me how to properly wire the pt for USA? Im a little confused?

Thanks,
Jon

Correction, at the recto pin 1 reads 274vac with the meter chassis grounded. 555vac with the meter on pin 1 and pin 7.

Im going frickin cookoo!!

Voltages DC, Left to right. THe first number is my voltage, the second is the number what it should be on the layout

10/12
280/340
158/217
161/220
31/62
69/75
33/52
223/272
137/180
1.38/1.5
121/155
121/155
.75/1.0
.75/1.0

No that's OK I have a 5 watter there too.

I don't think ANY wires on the primary should be grounded!! Let me take another look though.

viewtopic.php?t=689
Down aways there is the 120v pt wiring.
That green/yellow is the filament centertap and it is grounded so that's ok.
Make sure you're using the Black and the Black/white for the primary.
Stew

I checked the layout you posted a link to, its all good. Any other suggestions?

What's the voltage of your ac receptical ie. the voltage at the wall plate?