Re: 465M HV Multiplier

Fabio Trevisan

I may be asking a silly question and I may have missed you mentioned that
on the previous messages... but this thread is quite long to go over it.
Can you confirm that when you say you have the multiplier disconnected,
you're talking about just the connection between T550 pin 10 to U550 pin 11.

I`m asking that because I`m puzzled / confused by when you say you're
measuring 200VAC at the 2kV output of the transformer because, just from
the expectation of measuring 2kVAC out of the transformer is *per se*
rather extraordinary as it's not at all common for anyone to have an AC
voltmeter capable of measuring that kind of voltage at that kind of
frequency (30 to 40KHz).

If when you say you disconnect the multiplier, you confirm you're just
disconnecting T550 pin 10, from U550 pin 11, and if by disconnecting this
alone is enough for your fuse not to blow and for the current draw to
reamin at reasonable levels, then there's almost nothing else that could be
wrong besides the multiplier itself, even if you say the multiplier is
doing its thing at lower voltages.
Like other member mentioned the multiplier may be bad but maybe only
showing its ugly face when forced to work at the rated voltage.

Yet, if you're disconnecting only the multiplier, but keeping the remaining
of the U550 connected, than you should have no problem measuring the -2kV
at the OUTPUT of the U550, either at pin 9, or even at pin 6, in DC well
said and this should be good enough to tell the remaining of this circuit
is working well.

Also, you can confirm / measure if the circuit is oscillating correctly
measuring frequency on the primary side of T550 (if you have means to
measure frequency).



2017-10-09 12:26 GMT-03:00 Barry n4buq@... [TekScopes] <

If the oscillator is not oscillating, then there will be
no voltage on any secondary winding.

If the 2KV winding is shorted, it will be shorted irrespective
of what you do to the tripler. Removing the tripler will not
fix a short on the 2KV winding... and yet it does stop the
oscillator from blowing the fuse.

Not meaning to be silly, but are you sure you are measuring
AC with AC ranges, and DC with DC ranges?

I would replace the HV module.

-Chuck Harris
In the context of my previous escapade, that's not really a silly
question. I'm pretty sure I was measuring AC and DC properly (this time...)
but will go back and double-check those readings.

Thanks again to everyone on the list for being patient with me with all
this. I realize it's gone on a long time now. Hopefully I can find/fix it
before too much longer.

Barry - N4BUQ

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