Re: Amplifone VR2 problem

Page 25 of the HV deflection guide says "Do not panic if your
readings are not exactly +/- 24. The 5w 50-ohm resistors can make
your readings a bit wacky when there is no load on the regulators.

If you are actually blowing regulators it isn't the -36V that is
causing it. My working HV board gives +28 at VR1 and -36V at VR2
which is the exact same as your readings. Sounds like your
regulators are working fine if you are using the test methods in the
guide to get these readings. I would recommend reading and following
the 11 test procedures on pages 23 through 27.

Jonathan

On Fri, 02 May 2003 21:44:17 -0700, Tony Jones wrote:
>
>I'm rebuilding an Amplifone High Voltage pcb.
>
>Followed the FAQ instructions, tested everything, replaced
regulators
>with 1.5A versions, recapped (correct polarity).
>
>Testing with the BU406D removed, I get +-36V from deflection pcb
>J103.
>
>Get a regulated +28V from VR1 but regulated=input (-36V) from VR2.
>
>At first I thought it was odd that I had continuity between the case
>of
>VR2 and the heatsink (I am using an insulator and a plastic screw)
>but my
>working HV board does the same, I'm guessing I'm reading a path
>through
>VR1 which isn't insulated.
>
>So, am I blowing regulators? I installed a regular 1A 7924 in place
>(as I don't have that many CVs) but got exactly the same problem.
>
>Thanks!
>
>Tony
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Received on Sat May 3 18:43:15 2003