Roland SH-7 -1978    Weight=? Lbs. Number Manufactured = ? MRP = $

Circuit Overview:
     Certainly one of the more elaborate analog subtractive synths. Will review circuit when I get time.

Service Tips:
     Here's a letter from 10/22/19

Hello,

First I would like to say that I love your website and the way ou help people to service their synth by theirselves !
I sometimes take a look at your website when I need some few tips for my repairs.
I recently got a Sh-7 I pretty bad shape and couldn’t find any tips anywhere so I serviced it myself checking the service manual and probing with my oscilloscope.

I found out all the problems so I would like to share with you to help others as you helped me.

Here is the problems I was having and what I did to repair It :

LFO Problem, no oscillation and when I was moving the amount of LFO on the VCo it was like a bender, changing the pitch constantly without modulation,
It turned it it was the 4558’s OP Amp on the LFO circuit board.

I was having sone problems on the VCO 1, No waveforms.
It was a problem with the OP ams as well :
Changed IC310 and 312 (LM301 and CA3140)
I changed the 4558 as well as the SH-7 was pretty bad.

Problem on the KCV board,
The hold parameter was not steady, when using the hold, when I released the key, the tune was slowly going up infinitely,
The problem came from the Transistor ITS30456, It is obsolete now so I just took 2 matched transistor as an equivalent and now the hold is not detuning anymore.

So other small problems but it was just some bad faders or other cleaning issues.

Thank you again for all of your work,

Hope it would help someone,

Best regards,

Valentin.