4 Sep
2014
4 Sep
'14
11:45 a.m.
Hi Tony,
On Wed, Sep 3, 2014 at 2:15 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Remember a mains filter could be part of the mains input conenctor. If
it's an IEC 320 type (the 'kettle plug' as used on PCs, etc) look at the
iback of the plug. a metal box there is oftne a mains filter.
If not, then I would disconenct the transformer primary and secondary
leads. Use a 'megger' (HV isulation tester) with a test votlage of 500V
or 100V on the mains input circuit (that is, between the live and neutral
input wires conencted together and the case) to check the inoput
conenctor, fusehold, switch, etc. Then use the megger to test between the
transformer primary widing and the core and then betwene the priamry
windign and the econdaries.
Hopefully it will not be thr transformer. I've had a surpsing number of
switches go leaky over the years.
Is there a amins filter circuit in this machine?
Nope.
Note that htis does not mean the capacitor is leaky. A capacitor will pass
an AC current, which is what the mains is.
Bear in mind, that while the workings of board-level digital circuits are
still
fairly new territory to me, I do have 20 yrs. experience as a
general-purpose electrical / electronic technician, mostly in the field of
analog / vacuum tube audio, radio and vehicle electrical systems. These
days, I specialize in cal & repair of vacuum tube testers and other older,
tube-based instruments.