Re: [sdiy] juno 60 death

[Roman]

hi,
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.
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) and if there is no connection between them. Then power up only transformer and measure voltage at secondary windings shorted with 1k resistor. Without it DVM would also show voltages between windings due to parasitic capacitance of transformer. Then check the bridge and regulators.

Or you can power the juno from external power supply to see if it still works. AFAIR it requires +/-15V and +5V.

Roman

---- Wiadomość Oryginalna ----
Od: gregory zifcak <zifcak at hotmail.com>
Do: synth-diy at dropmix.xs4all.nl
Data: Thu, 06 May 2004 16:00:16 -0700
Temat: [sdiy] juno 60 death

>hello,
>
>a friend's juno 60 suddenly stopped showing any signs of life. the fuse 
>appears to be intact. i measured some points with my meter, and it looks 
>like the transformer is putting OUT 120v. this is not normal right? it looks 
>to me like the transformer has two outputs: 26vac and 18vdc. is this 
>correct? what appears to be the two outputs both read 120vac. can anyone 
>corroborate my hunches? i suppose i'll need to find a replacement. any 
>leads? also, wouldn't 120vac damage the voltage regulators and caps? they 
>don't look burned at all.
>
>thanks for any help,
>greg
>
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