Drip 670 v3 melting transformers wax

[schrobbelbop]

My drip 670 V3 is melting the wax out
The sowter transformers and it covers the whole pcb it was angled in the rack so it’s across all the tube sockets all piling up at some HV connections…

Now it’s shorting hv somewhere when the unit is on operating temps and I switch it. Off and on again. I suspect a inrush current shorting somewhere by all of that wax everywhere touching 240/440v is that even possible ?
My 2nd rectifier tube (5ar4) has died

How do other cool this design? Or is it just a bad design and do I need to get those transformers away from the tubes?
Or is forced cooling the way to go?

 

[emrr]

If you've had 2 rectifiers die it would suggest there's a short somewhere, creating the excess heat.

 

[beatnik]

Since production has moved to Carnhill I have experienced they changed the potting compound and often the transformers are shaking inside the shielding cans, you have to warm them with a heat gun to stabilise them again. It seems most wax melts below 85 Celsius so it's actually below the rating of electrolytic capacitors ? lt seems just a stupid idea to use wax as a potting compound. What other manufacturers use ?

On another note it's a bit silly that Drip did not put any provision for a HT fuse which would have prevented such a mess.

 

[meloamantis]

Moving those transformers further away from the tubes might help with the heat, or adding some fans for forced cooling could be the way to go. Definitely clean up the wax buildup and check those HV connections before it causes more problems

 

[schrobbelbop]

Cleaned it and rebuild, reconnected it. There was a 6973 tube a little black inside, replaced that one. It’s running all fine now.
There’s just some little noise sputters in the left channel. I suspect I damaged one of its 6386 by swapping them hot a few times, and that might also have been the reason for shorts on the HV?

I might let the tubes check with a tube tester.
The JJ 6386 have become insanely expensive! Is there a proper way of testing them. I could also test them one by one In my sta level I guess. But would love to have them matched up again