[Heathkit] Popping DX-40

[Bill Stewart]

Hi Kevin,
Tnx for the info. Yes, with the 5U4GB out, there is no noise. My previous post tells of the latest findings. Not sure if it is cured, but there is hope. 

The sub'ed 'lytics were wired in, not parallel.

The 'floating' xformer would only be done in an extreme situation and would be amply labeled and documented. Like you, I realize the danger of this 'fix'. 
73 de Bill K4JYS

----- Original Message -----
From: "Kevin Ward" <n2ie at arrl.net>
To: heathkit at mailman.qth.net, cwopr at embarqmail.com
Sent: Thursday, October 29, 2009 4:19:49 PM GMT -05:00 US/Canada Eastern
Subject: Re: [Heathkit] Popping DX-40

Bill -

You indicate you tested the rig with all tubes removed except the 5U4.  Did you try removing it also?  If the arcing sound goes away with the rectifier removed, at least the high voltage winding is not arcing inside the transformer case.  Of course, the 5-volt winding could be doing so.  

If you find that the arcing stops with the 5U4 removed, you could solid-state the power supply and get the filament winding out of the picture.  The DX-40 is robust enough to handle the slight increase in B+ that would result.  

You mentioned that you "Sub'ed the lytics."  I hope that means you disconnected the on-board capacitors, and you didn't just connect another cap in parallel.  

Last, but most important, I want to caution you against doing something very dangerous.  Your comment was, " I vaguely recall something about raising the trans. above the chassis with plastic spacers and screws (internal arcing to the case?)....was this the solution to this problem?"

DON'T DO THIS!  

It could come back to bite you . . . or worse, someone else.  I don't think I need to elaborate.

Good luck.  We're all waiting to see how this works out.

73,
Kevin  N2IE