Recap: No display - no high voltage - recently rebuilt HV board and
installed new Wintron HVT. Worked fine for a month. When it stopped
working I could briefly hear a strange noise. There was no smoke or
smell.
OK, here is the latest:
Test results: My BU406D is fine. All my resistors are fine.
Q1/3/4/5 are fine. My +30/-30 and +24/-24 are fine. VR1/2 are fine.
But I have no display, and the red overvoltage LED comes on. I read
that I might be getting false readings since the overvoltage was not
allowing my tests to be under load, so I pulled one leg of CR1 by R7
(DANGER - XRAYS!) to run my tests since I had tried everything else I
could think of...
THE NOISE IS BACK! After pulling CR1 the noise is back big time! I
am 99% sure it is coming from the Wintron HVT. It sounds like
somebody slowly shutting a squeaky door in between 2 power lines
(lots of static and popping at changing frequencies). With the
overvoltage disabled, it will make noise for as long as I dare leave
it on. I checked my voltages and they are still good. I seem to
have no high voltage even with the overvoltage disabled.
There is no smoke, no smell, and the HVT is cold to the touch.
Sound like a bad HVT? It is practically brand new. Has anybody had
any other part of the board make that sound? I really don't want to
start putting my ear up to parts on the board. It sure seems like
the HVT as near as I can tell.
I'd rather not have to build a LOPT tester. Would somebody consider
renting me one? Or, I might just send back the HVT to Wintron and
let them test it.
Any advice appreciated!
On Sun, 11 May 2003 18:41:28 -0400 (EDT), Christopher X. Candreva
wrote:
>On Sun, 11 May 2003, Jonathan Stanley wrote:
>
>>and had set it to exactly +180V. I haven't actually pulled the
>>BU406D yet, but I did make sure the collector is ohming out with
>>the
>>heatsink and that the two legs have continuity down the traces.
>
>One thing I've learned, if ANYTHING goes bad, the BU will blow. It
>is almost
>certainly blown -- pull and check it. While you are at it check C8
>(or
>whatever the high-voltage poly-p cap is). If your meter doesn't have
>a cap
>checker, it's a god investment (as is the LOPT checker)
>
>When you buy BU406D's get at least a dozen.
>
>
>==========================================================
>Chris Candreva -- chris@westnet.com -- (914) 967-7816
>WestNet Internet Services of Westchester
>http://www.westnet.com/
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Received on Sun May 25 20:10:57 2003
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