[sdiy] Roland SH-101 power supply

[Richie Burnett]

> What I'd like to know is how do they get such a range of voltages (-5V to 
> +15V is a 20V range) from a 9V supply?....

Flyback converter consisting of TR1, TR2, T1, (left side of main circuit 
diagram,) marked POWER SUPPLY  ;-))

-Richie,

-----Original Message----- 
From: Tom Wiltshire
Sent: Friday, August 26, 2016 7:11 PM
To: synthdiy diy
Subject: [sdiy] Roland SH-101 power supply

Hi All,

The Roland SH-101 can be run off 6 x 1.5V batteries, which gives it a 
nominal 9V input. It can also be run from a 9-12V AC-DC adaptor.

I've been looking at the service manual and there are various symbols used 
for the voltages, but they're only mentioned where they go to some connector 
or other.

There are:

Up Arrow: +9V
Half-filled full up triangle: +15V
Filled full up triangle: +14V
Gnd: Ground (at least this one is obvious)
Straight line: +5V
Unfilled down triangle: -5V

What I'd like to know is how do they get such a range of voltages (-5V to 
+15V is a 20V range) from a 9V supply? I don't see anything that looks like 
a voltage booster on the schematic, but I'm not well-versed in such things.

Thanks,
Tom




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