Power Transformer Buzz

[dehringer]

I recently complete my Kaiju kit and the power transformer is noticeably buzzing.  When the 300Bs are removed, the buzzing almost completely goes away and is barely audible.

I painted the chassis, transformer bell, and the chokes. I believe I had scraped away the paint from all relevant areas along the way. There is continuity between the unpainted underside of the transformer bell and the safety ground. Are there any notable places I should be triple checking that I have contact with the unpainted metal?

I've gone back through the manual step-by-step and have reflowed many of the solder joints. Everything appeared ok but after looking at it for so long I might need to take some time away from the kit before anything stands out. Given the symptoms, are there any specific areas I might focus in on?

I've attached a number of pictures in case anything stands out.

 

[Paul Birkeland]

What are the DC voltages on each 4 pin socket with tubes installed?

 

[dehringer]

With both pairs of tubes installed, the voltages are as follows:

B1 - 71v
B2 - 416v
B3 - 34mv
B4 - 71v

C1 - 70v
C2 - 416v
C3 - 38mv
C4 - 70v

 

[Paul Birkeland]

I would tighten down the power transformer screws till they are very tight.

 

[dehringer]

I tightened down the power transformer screws very tight.  The screw with the 57-61 terminal strip was a bit difficult to tighten down while keeping the strip straight.  But the buzz remains.

 

[Paul Birkeland]

About when was this kit ordered?  Way back shortly after we released the kit, our winder did a small revision to the power transformer to quiet it down a bit, but that was many years ago. 

If that's not what we are working against, we can arrange to help you get that power transformer sent back to us for exchange.

-PB

 

[dehringer]

My kit was ordered recently, in July of this year.

 

[Paul Birkeland]

I would drop an e-mail to queen@bottlehead.com and let her know your name and order number, then paste a link to this thread and let her know that you need to exchange your Kaiju PT.

-PB

 

[dehringer]

Will do.  Thanks for the help Paul!