Re: More Star Wars HV problems, help please?

OK, I've checked everything else out I can and only found one item
I'm not sure on:

At the point where the grey Wintron wire attaches to the board I am
measuring 0 volts. Grey says "filiment hot". What voltage should be
at this location, and does this prove / disprove the HVT being the
problem or something on the board?

Thanks everybody!

On Mon, 26 May 2003 13:49:51 +1000, Marc Alexander wrote:
>
>I've gotta say it sounds like the sensible thing to send the HVT
>back to Wintron to be sure.
>Probably a shorted turn from the HV output back to the B+ out.
>
>Looking at the schematics it could be the seperate focus block
>though as a long shot, so if you can check and/or replace the focus
>block that
>would be about the last thing to test.
>The focus block is the feedback loop from the bottom of the HV
>winding
>back to the overvoltage detection circuit, and is also the ground
>path from
>the HVT output.
>You could short the connection between the HVT to the focus block
>directly to
>GND as a test, you won't get a picture, but if the HVT still makes
>noise you'll know it's the HVT.
>
>Is the DAG GND connection good from the HV board to the tube and
>wiring?
>It's the final grounding path from the HVT and focus block, through
>the
>HV overvoltage adjust pot.
>
>Have you replaced the W1 jumper with wire?
>
>HVT's do fail sometimes regardless of age, there's a lot of high
>voltage
>there to break a minor production fault.
>
>Do you have a HV probe? When the noise is going are you getting any
>voltage out of the HVT?
>
>Cheers,
>
>Marc
>
>----- Original Message -----
>From: "Jonathan Stanley" <jstanley1@cfl.rr.com>
>To: <vectorlist@synthcom.com>
>Sent: Monday, May 26, 2003 1:11 PM
>Subject: Re: VECTOR: More Star Wars HV problems, help please?
>
>
>>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!
>
>
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Received on Fri May 30 14:35:16 2003