[Boatanchors] National HRO-60 power transformer need

Tue, 29 Jan 2002 04:33:36 -0000

John:
It may be possible to repair.
Remove transformer, power up with light bulb in series with supply.
If bulb very bright likely to be shorted turn in primary, difficult to
treat.
Otherwise check volts on primary, then volts on secondary windings.
Unlikely to be problem with any of the filament windings.
Most likely shorted turn in secondary.
Turn off power, use ohmmeter to check for shorts between windings, or from
windings to core.
Strip transformer covers, look for burned areas or shorted leads.
If filament windings look OK,
Remove core from laminations, remove filament windings, counting turns for
each.
If problem in HT winding not obvious, start unwinding until problem is
identified.
With luck it may be towards  outside of winding. If there is an
electrostatic shield between primary and secondary short may well be there.
It is quite feasible to rewind by hand especially if the primary is intact.
If primary shot may be woirth taking to specialist to rewind, but will not
be cheap and may be better to look for substitute.
73

end
Barry Kirkwood PhD ZL1DD
Signal Hill Homestay
66 Cory Road
Palm Beach
Waiheke Island 1240
NEW ZEALAND
www.waiheke.co.nz/signal.htm
----- Original Message -----
From: John Gainsborough <[email protected]>
To: <[email protected]>
Sent: Tuesday, January 29, 2002 2:36 AM
Subject: [Boatanchors] National HRO-60 power transformer need

> I recently acquired a beautiful looking HRO Sixty in great cosmetic
> condition, both inside and outside. I should have known that the price was
> too good to be true! The power transformer insists on blowing fuses!
>
> Do any of you knowledgible folk know where I might  find an HRO
replacement,
> or perhaps have a receiver in poor shape but with a good power
transformer?
>
> Apart from the transformer, the receiver performs well when fed via a
bench
> supply.
>
> 73,
>
> John, KM6LJ
>
>
>
>
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