Hi,
Keep in mind that I am not an electronics expert, but I had the same
problem with an old Metz 45CT-1. I repaired it myself. This is how I did
it:
* control of circuitry of the flash contact (with a DC-ohmmeter, resistance
has to be very low, was OK)
* trigger coil (with a DC-ohmmeter, resistance has to be very low, was OK)
* condensator (with a voltmeter and again with an oscilloscope. This was
the problem: although it seemed to load fine, the charge was to low to
ionize the xenon tube via the trigger coil, thus producing a flash...I
don't remember the exact value, I think it was about 40V).
I replaced the condensator. It's OK now!
Some other possibilities:
* thyristor (difficult to test, except when you are an expert in
electronics. One could try to connect K and A with a little screwdriver,
but imho that's a very rude method...). It can be tested by replacing it...
Thyristors are cheap...
* xenon tube (almost impossible to test. As good tubes (real good tubes:
there's a lot of junk available...) are expensive it can be tested by
placing it in another circuit, capable of firing at well-defined loads
(5Ws, 10Ws...). Building such an apparatus is simple....
NOT SHOUTING, ONLY EMPHASIZING:
KEEP IN MIND THAT THE CONDENSATOR CAN CARRIE VERY HEAVY LOADS (TYPICALLY
SEVERAL 100 V). THIS CAN BE VERY DANGEROUS! WHEN WORKING ON A FLASH, ONE
SHOULD, FIRST OF ALL, DISCHARGE THE CONDENSATOR BY CONNECTING THE TWO POLES
WITH A 10K OHM RESISTOR. THE DISCHARGE HAS TO BE MONITORED WITH A
VOLTMETER... THIS HAS TO BE DONE EVERY TIME BEFORE CONNECTING METERS ETC TO
THE FLASH...
Good luck!
Yvan Lindekens.
----------
> Van: John Gaasland <kayak@xxxxxxx>
> Aan: olympus@xxxxxxxxxxxxxxx
> Onderwerp: [OM] Broken T-20 flash
> Datum: zaterdag 9 januari 1999 21:55
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