Vintage Synth Repair

Like to introduce myself...

I've been a producer and Live Pa artist for 10 yrs in Toronto into
techno...

I'm an avid DIY'r and have modded/built the following gear...

Moog MG1 - convert to midi (synjack)
DR-110 - breakout box to cahnge voice parameters (tuning decay snap)
SIDbox V2 - built a stereo SID from the uCapps site using the 6581
sid chip... Presently building a mono version

Gear List

Ableton Live

SH-101
TR-707
DR-110
Tama Techstar-TS305
Juno-60
JX-3P with PG200
Nord Micro Modular
Yamaha A4000
BCR2000
Moog MG1
SIDbox
Mackie 1202
RNC compressor
M-audio FW410




Purchased a red 101 for $100 about a year ago and have resurrected it
from the near dead... It was coverd in grime, has a dead F# key,
transpose toggle snapped off, missing battery cover, and broken pitch
bender handle... Fixed all of those but still can't get the dead key
working will try again later...

Followed the tuning calibration document and still have tuning issues
and have discovered it is the power switch... When wiggling the power
switch it will change tune... I removed the switch and soaked it in
electrical cleaner and resoldered it to find no change...

So does anyone know which of the 8 traces on the switch PCB can be
bridged to bypass the switch?

As for my intro I do not mean to come off as a braggart and just want
to give some background about myself...

Thanks...

bri.

Hey Bri, I've owned around five SH-101's and every single one did what you talk about. Wiggle the power knob and the pitch changed..however if you didnt wobble it the pitch was fine so it was never really an issue in use.
 
Phil.
 
 


--- On Wed, 3/12/08, cosmosuave <race_slick@yahoo.com> wrote:

From: cosmosuave <race_slick@...>
Subject: [vintagesynthrepair] New Memeber SH-101 (How to Hardwire Power Switch?)
To: vintagesynthrepair@yahoogroups.com
Date: Wednesday, 3 December, 2008, 10:06 PM






Like to introduce myself...

I've been a producer and Live Pa artist for 10 yrs in Toronto into
techno...

I'm an avid DIY'r and have modded/built the following gear...

Moog MG1 - convert to midi (synjack)
DR-110 - breakout box to cahnge voice parameters (tuning decay snap)
SIDbox V2 - built a stereo SID from the uCapps site using the 6581
sid chip... Presently building a mono version

Gear List

Ableton Live

SH-101
TR-707
DR-110
Tama Techstar-TS305
Juno-60
JX-3P with PG200
Nord Micro Modular
Yamaha A4000
BCR2000
Moog MG1
SIDbox
Mackie 1202
RNC compressor
M-audio FW410

Purchased a red 101 for $100 about a year ago and have resurrected it
from the near dead... It was coverd in grime, has a dead F# key,
transpose toggle snapped off, missing battery cover, and broken pitch
bender handle... Fixed all of those but still can't get the dead key
working will try again later...

Followed the tuning calibration document and still have tuning issues
and have discovered it is the power switch... When wiggling the power
switch it will change tune... I removed the switch and soaked it in
electrical cleaner and resoldered it to find no change...

So does anyone know which of the 8 traces on the switch PCB can be
bridged to bypass the switch?

As for my intro I do not mean to come off as a braggart and just want
to give some background about myself...

Thanks...

bri.

> Followed the tuning calibration document and still have tuning issues
> and have discovered it is the power switch... When wiggling the power
> switch it will change tune... I removed the switch and soaked it in
> electrical cleaner and resoldered it to find no change...

If you flex the switch and got that symptom and then changed it out and still 
get it,  then the switch isn't the problem.  I didn't think it would be,  
actually.

What's happening is that you're flexing the board,  and that's affecing 
something else.  From the stuff I snipped it sounds to me like that 
particular instrument was pretty sadly abused,  so you may need to look 
further before you nail the problem.

A good strong light,  maybe a magnifying glass or a pair of reading glasses,  
and some patience and you'll probably be able to track that down.

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

I would concur with Roy.  Intermittent solder joint or circuit trace
is likely to be responsible.

You could measure voltage (resistance) the switch when on (off) and
determine how to 'hot wire' the power switch.  It would eliminate the
switch as a possibility.

I am sure you will be able to figure it out.

-Mike


--- In vintagesynthrepair@yahoogroups.com, "Roy J. Tellason"
<rtellason@...> wrote:
>
> > Followed the tuning calibration document and still have tuning issues
> > and have discovered it is the power switch... When wiggling the power
> > switch it will change tune... I removed the switch and soaked it in
> > electrical cleaner and resoldered it to find no change...
> 
> If you flex the switch and got that symptom and then changed it out
and still 
> get it,  then the switch isn't the problem.  I didn't think it would
be,  
> actually.
> 
> What's happening is that you're flexing the board,  and that's affecing 
> something else.  From the stuff I snipped it sounds to me like that 
> particular instrument was pretty sadly abused,  so you may need to look 
> further before you nail the problem.
> 
> A good strong light,  maybe a magnifying glass or a pair of reading
glasses,  
> and some patience and you'll probably be able to track that down.
> 
> -- 
> Member of the toughest, meanest, deadliest, most unrelenting -- and
> ablest -- form of life in this section of space,  a critter that can
> be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet
Masters"
> -
> Information is more dangerous than cannon to a society ruled by
lies. --James 
> M Dakin
>

--- In vintagesynthrepair@yahoogroups.com, "Roy J. Tellason" 
<rtellason@...> wrote:
>
> > Followed the tuning calibration document and still have tuning 
issues
> > and have discovered it is the power switch... When wiggling the 
power
> > switch it will change tune... I removed the switch and soaked it 
in
> > electrical cleaner and resoldered it to find no change...
> 
> If you flex the switch and got that symptom and then changed it out 
and still 
> get it,  then the switch isn't the problem.  I didn't think it 
would be,  
> actually.
> 
> What's happening is that you're flexing the board,  and that's 
affecing 
> something else.  From the stuff I snipped it sounds to me like that 
> particular instrument was pretty sadly abused,  so you may need to 
look 
> further before you nail the problem.
> 
> A good strong light,  maybe a magnifying glass or a pair of reading 
glasses,  
> and some patience and you'll probably be able to track that down.
> 
> -- 
> Member of the toughest, meanest, deadliest, most unrelenting -- and
> ablest -- form of life in this section of space,  a critter that can
> be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet 
Masters"
> -
> Information is more dangerous than cannon to a society ruled by 
lies. --James 
> M Dakin
>
Thanks Roy I'll go with your recommendation and see where it takes 
me...

bri.

In case my message didnt get through...
 
Like I said before I had 5 or so SH-101's most of them in mint, as new condition. They all did this. I couldn't find a fault. It never affected opreration so I put it down to a design anomaly.
 
Phil.
 


--- On Thu, 4/12/08, Roy J. Tellason <rtellason@...> wrote:

From: Roy J. Tellason <rtellason@...>
Subject: Re: [vintagesynthrepair] New Memeber SH-101 (How to Hardwire Power Switch?)
To: vintagesynthrepair@yahoogroups.com
Date: Thursday, 4 December, 2008, 1:53 AM






> Followed the tuning calibration document and still have tuning issues
> and have discovered it is the power switch... When wiggling the power
> switch it will change tune... I removed the switch and soaked it in
> electrical cleaner and resoldered it to find no change...

If you flex the switch and got that symptom and then changed it out and still 
get it, then the switch isn't the problem. I didn't think it would be, 
actually.

What's happening is that you're flexing the board, and that's affecing 
something else. From the stuff I snipped it sounds to me like that 
particular instrument was pretty sadly abused, so you may need to look 
further before you nail the problem.

A good strong light, maybe a magnifying glass or a pair of reading glasses, 
and some patience and you'll probably be able to track that down.

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

I've also come across 2 or 3 SH-101's that had this same fault.
 
From memory, the SH-101's internal power regulating / DC-DC conversion is really weird, and poor contacts in the switch cause the 101's to drop it's tuning a bit.
 
On one of my 101's, even playing the keyboard near the power switch did cause the 101 to drop tuning by about a semitone.
I worked my power switch about 1000 times (with no power attached!) and this worked the switches contacts, and helped fix the problem heaps. ( $0.00 solution)
 
You could remove the switch a wash it out with alcohol.. but I never tried that.
 
Regards
Mike

--- On Thu, 4/12/08, Philip <eggwheatis@...> wrote:

From: Philip <eggwheatis@...>
Subject: Re: [vintagesynthrepair] New Memeber SH-101 (How to Hardwire Power Switch?)
To: vintagesynthrepair@yahoogroups.com
Received: Thursday, 4 December, 2008, 1:06 PM











In case my message didnt get through...
 
Like I said before I had 5 or so SH-101's most of them in mint, as new condition. They all did this. I couldn't find a fault. It never affected opreration so I put it down to a design anomaly.
 
Phil.
 


--- On Thu, 4/12/08, Roy J. Tellason <rtellason@verizon. net> wrote:

From: Roy J. Tellason <rtellason@verizon. net>
Subject: Re: [vintagesynthrepair ] New Memeber SH-101 (How to Hardwire Power Switch?)
To: vintagesynthrepair@ yahoogroups. com
Date: Thursday, 4 December, 2008, 1:53 AM




> Followed the tuning calibration document and still have tuning issues
> and have discovered it is the power switch... When wiggling the power
> switch it will change tune... I removed the switch and soaked it in
> electrical cleaner and resoldered it to find no change...

If you flex the switch and got that symptom and then changed it out and still 
get it, then the switch isn't the problem. I didn't think it would be, 
actually.

What's happening is that you're flexing the board, and that's affecing 
something else. From the stuff I snipped it sounds to me like that 
particular instrument was pretty sadly abused, so you may need to look 
further before you nail the problem.

A good strong light, maybe a magnifying glass or a pair of reading glasses, 
and some patience and you'll probably be able to track that down.

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

 














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> 
> So does anyone know which of the 8 traces on the switch PCB can be
> bridged to bypass the switch?

This is relatively easy to figure out with an multimeter. With the
instrument unplugged (no power), just test the resistance between
points on the switch while it's in the ON position. Wherever you get 0
Ohm means those two points are connected when the unit is ON. Just
solder a wire between those and you'll bypass the switch. You can also
do the same probing with the unit OFF, which will help you understand
what's changing between ON and OFF states, and thus figure our the
switch's inner logic.

J.F.

--- In vintagesynthrepair@yahoogroups.com, "octogonaltar" <amnesie@...> 
wrote:
>
> > 
> > So does anyone know which of the 8 traces on the switch PCB can be
> > bridged to bypass the switch?
> 
> This is relatively easy to figure out with an multimeter. With the
> instrument unplugged (no power), just test the resistance between
> points on the switch while it's in the ON position. Wherever you get 0
> Ohm means those two points are connected when the unit is ON. Just
> solder a wire between those and you'll bypass the switch. You can also
> do the same probing with the unit OFF, which will help you understand
> what's changing between ON and OFF states, and thus figure our the
> switch's inner logic.
> 
> J.F.
>
Thanks why didn't I think of that... I'll let you know how it went...

bri.