Dynaco st-70’ low voltage

I have installed a Dynakitparts PC-3 , bias kit, 10k pots, and the 80,40,30,20 quad cap.
My is is low voltage at section 3 of the quad cap ,it is only 282v all other readings are spot on . I have tried several rectifier tubes with no change.any idea where to look .
Thank you.

Babgrip wrote:I have installed a Dynakitparts PC-3 , bias kit, 10k pots, and the 80,40,30,20 quad cap.
My is is low voltage at section 3 of the quad cap ,it is only 282v all other readings are spot on . I have tried several rectifier tubes with no change.any idea where to look .
Thank you.

With "section 3 of the quad cap" do you mean 'A' in the manual ? That is
supposed to have 305 volt ? If that is low and 'B' has about 375 Volt
then the 22K resistor is bad. ( assuming orignal board is used )

Sorry about the confusion the pictures did not upload. Section 3 would be the triangle going to eyelet # 19 on the pc board which I believe is the B+ to the 7199’s. Voltage should be 420-445 it is reading 282. I will check the 22k resistor again, it was right at 10% drift and I did not have a new one on hand so I reused it . Hopefully that is all the problem is.
Thank you for your advice.

Babgrip wrote:Sorry about the confusion the pictures did not upload. Section 3 would be the triangle going to eyelet # 19 on the pc board which I believe is the B+ to the 7199’s. Voltage should be 420-445 it is reading 282. I will check the 22k resistor again, it was right at 10% drift and I did not have a new one on hand so I reused it . Hopefully that is all the problem is.
Thank you for your advice.

eyelet 19 is connected to 'A' which is nominally 305 Volt, so it's not that far.
435 is the top voltage according to the manual and it's at the first cap 'D'
( pin 2 and 8 on the GZ34)
Section 'A is marked with a square,
'B' a triangle
'C' nothing
'D' a half circle
At lest on the caps dynaco used.

Compare with the manual.

I hope there is less confusion now.

Section A voltage 282vdc Section B voltage 364vdc both voltages are low. According to stock manual A is 23vdc low and B is 11vdc low not to bad. Based on the voltage chart that is found on this forum voltage on section A should fall between 420-455 section B 380-430 a big difference. I have used this chart before on other ST-70’s and found it to be accurate. Also
Note that the upgraded quad cap is installed with triangle facing towards the front of the amp so the symbols are in different positions than the stock cap.
All readings taken at 117vac line

Babgrip wrote:Section A voltage 282vdc Section B voltage 364vdc both voltages are low. According to stock manual  A is 23vdc low and B is 11vdc low not to bad. Based on the voltage chart that  is found on this forum voltage on section A should fall between 420-455 section B 380-430 a big difference. I have used this chart before on other ST-70’s and found it to be accurate. Also
Note that the upgraded quad cap is installed with triangle facing towards the front of the amp so the symbols are in different  positions than the stock cap.
All readings taken at 117vac line

I think you are close then.
Looking at the manual A is last in chain and feeds the eyalet 19
B will feed eyelet 20
C will feed the midpoint of the OT.

If both A and B is low, maybe the 6.8k resistor is a little high ?

Resistors on order