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Re: Warm up time on old capacitor checker



Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

Tesla list wrote:
 >
 > Original poster: "John Richardson" <jprich-at-up-dot-net>
 >
 > He Ed and All,
 >
 > The model is an old IT-28.  There are three choices for caps:  electrolytic,
 > min'lytic (?), and paper-mica-etc.  I was using the .01 range.  There is a
 > switch for bridge, leakage, and discharge.  There is also a power factor
 > dial, as well as a 0-600 voltage knob.  I was spinning and flicking
 > everything like the Wizard in the Wizard of Oz, and didn't get a whole lot
 > to happen.  I did have it set on bridge, and I tried all three capacitor
 > switch positions.  The switch marked generator has two positions, internal
 > and external.  I tried both, but I don't know what it should be set on.  I
 > checked BAMA  (Boat Anchor Manuals Association) for an online manual, but
 > their server has problems.  Used or photocopied ones are about fifteen
 > bucks, exceeding the cost of this thing by a factor of thirty.  Not gonna
 > happen.  Am I using this thing wrong, or is it new tube time?
 >
 > Thanks,
 > John Richardson

	I'll bet the tubes are OK.  10 minutes warmup is way too long for any
tube I've ever seen; 1 minute should be plenty.  I still suspect an open
resistor or leaky capacitor, which might have that long a time
constant.  Of course, long-distance diagnosis is a bit of a problem.
Wanta ship it out here to California so I can have a look at it.

	More seriously, you never really gave us the symptoms (as I recall).
What takes 10 minutes?  Indicator tube to light?  Time for it to open
and close?  By the way, do you know how to use it?  For paper or mica
capacitors you should start with the power factor knob set to zero, try
to balance the bridge and, when you get a dip, start advancing the PF
know to see if you can improve the balance.  Any decent capacitor will
have a PF less than 0.1%.

Ed