[sdiy] juno 60 death

[Ingo Debus]

Am Freitag, 07.05.04 um 09:13 Uhr schrieb Roman:

> if it shows 120V on the secondary, you probably need to find a 
> replacement for the Juno, not just transformer. The only posibility I 
> can think of is that there is a short circuit between primary and 
> secondary windings, or wires have been swapped. If you can't see any 
> burnt parts, that means it's not really 120V you are measuring, or 
> there must be some broken component early on the way from transformer, 
> like bridge rectifier or something in that area.
>

Another possibility I can think of is an open circuit (interrupted) 
secondary winding. A high impedance voltmeter would perhaps show the 
mains voltage coupled through the capacitance between the windings, 
assuming the rest of the circuitry doesn't load the (defective) 
secondary winding.


> First disconnect the transformer and measure all windings with 
> ohmmeter if they have reasonable resistance (few ohm on secondasy, up 
> to few hundred on primary)

Yes, this way you'll easily find out if the windings are ok or not. 
Careful when fiddling with an ohmmeter at a mains transformer: the back 
EMF when disconnecting the meter can give you a zap. Don't know if this 
is an issue with a modern DMM, but it can happen with an old analog 
meter.

Ingo