[sdiy] s[diy] re: SH-101 power supply transformer TR-1

[John Henson]

Hi Bill,
I have just put an SH101 to rest yesterday, after a ridiculous amount of 
time spent trying to get some joy out of it. The long time spent was 
just to get it into its diagnostics mode which had to be done in order 
to decide to fix or to bin.
I don't think 2N2222a's are particularly suitable for either TR1 or TR2.
TR1 should be a power transistor (A BD131 is a suitable european 
equivalent which I have used successfully many times which also fits the 
pinout perfectly) and TR2 can be almost any generic NPN with a HFE of 
about 400 (Again a Euro equivalent would be a BC184LC which also fits 
the pinout).
The Transistors used throughout most of the SH101 are generic Japanese 
types which can be scavenged from old VCR's, Monitors, cassette decks 
etc. which is where most of my stash comes from.
In the SH101 here, most of the Trannies are tiny versions of the real 
thing (as also in today's Juno 6 project).
The trannies marked 603 are equivalent to 2SC1815 and the ones marked 
115 are the 2SA1015 equivalents. They seem to be a direct swap, as I had 
to replace 7 trannies around the LED drivers and gate and clock in and 
out circuits.
In the case of this 101, the CEM3340 was missing, the filter chip is 
dead, the D to A converter is shot, and all bets are off for the VCA, 
and the envelope generator is dead.
Your second post came in as I was typing this, C4 is 330uF in this one 
and the inductor is also present. I suspect production moved faster than 
documentation.
I also suspect too much voltage as the culprit, but how much does to 
take to wipe out an IR3109 and a bunch of transistors rated at at least 
30 volts. A lot of the 101 is run from the unregulated input voltage, 
and from my experience, these are where the main problems are going to 
be after the power supply is fixed.
BTW, if the transformer is not present, then no power is dissipated in 
the TR1 tranny, hence it will of course run cold. In the working PSU in 
this 101, it just feels warm to the touch.
Regards,
John.

www.retroactivesynth.com

On 19/06/2011 18:13, bill bigrig wrote:
> howdy,
>
>   Finally installed 2 2n2222As in TR-1&  TR-2. Put in new R-8, 1 ohm, although the PCB says L1 and shows a coil icon. The 2 transistors get hot. I removed transformer T-1, unfortunately damaging it. Where does one find a replacement T-1, part #12449224, or a S1671140 coil, (DC/DC Converter)?
> Rig
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