Solid State Musical Organ just hissing....

[tedstruk]

I was wondering about solid state testing equipment, and scoping boards, when they are out of the circuit...
Most manufacturerers have equipment specifically designed for that.

This is a Gulbransen Equinox 2 musicomputer model 230 that refuses to make any noise other than a hiss that increases and decreases with the volume pedal...
What a grand organ machine this is, it is a rhythm section, full orchestra, vibrato, tremelo, reverb, and a leslie speaker all in a nice two keyboard package !
I don't even know how old it is...

 

[Robert_fay]

A hiss like a vacuum line leaking or an electrical hiss out of the speaker?

 

[Robert_fay]

Maybe look here this is an older forum, however sounds like they know their way around your organ.
https://www.organforum.com/forums/showthread.php?4650-Gulbransen-Equinox

 

[tedstruk]

The Gulbransen Equinox 2 Model 230 with the top down.. er up in this case.

Can't wait to see if I am any good at this stuff!

Any help with solid state diagnosis would be of invaluable assistance... how about a title for a good book under $20?

 

[kellys_eye]

Plug-in cards by the look of them. You will need the matching 'riser' card in order to access them for servicing.

 

[Alec_t]

Just a controllable hiss level suggests that at least the pre-amplifier and main amplifier sections are working. I'd start by checking any fuses, and the supply voltage(s) to the plug-in cards.
The organ schematic and/or service manual would be handy.