loud hum

[bucketofguts]

94.3

 

[bucketofguts]

I have been working this issue all day. Thank you for the help!

 

[Paul Birkeland]

Please post build photos.

 

[bucketofguts]

Will get some up tomorrow. Thanks for all the help today.

b~

 

[bucketofguts]

Here are the requested photos.

 

[Paul Birkeland]

What are the voltages at 13 and 15?

 

[bucketofguts]

#13 63.5V
#15 80V

Power on.
(Valves in)

 

[Paul Birkeland]

Are you using terminal 12 as your ground reference?

 

[bucketofguts]

yes

 

[bucketofguts]

BTW, thank you for your kind replies.

 

[Paul Birkeland]

What voltage do you see at terminal 22?

 

[bucketofguts]

97.6V

Power on
Valves in

Thank you. You are a gentleman and a scholar.

 

[Paul Birkeland]

Can you perform the AC voltage checks for the power transformer again?

I would also suggest reheating and adding some solder to all the solder joints with UF4007 diodes, especially if the transformer AC voltage checks are correct (which I suspect they are).

 

[bucketofguts]

Thank you. Will do.

is there a resistance value across those diodes that I should be looking for? Could one or both be faulty? (I see four)

Where are the ac terminals on the transformer?  help.....

 

[Paul Birkeland]

Page 29 in the manual provides the test for the power transformer.

When diodes like those fail, they tend to explode, so I don't believe that's worth looking at just yet.

 

[bucketofguts]

I measured 6.24 V AC as shown on page 29. (I have the exact same multi meter)

 

[Paul Birkeland]

How about for the high voltage winding?

 

[bucketofguts]

174.9

 

[Paul Birkeland]

What's the DC voltage between 20 and 21?

 

[bucketofguts]

Thank you ! That will have to wait. It is not my fault.


b~