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2010-09-29 by stompboxaron
Any tips on how to minimize any damage when turning on a vintage synth after 25+ years? One is a Prophet 5 and the other an Emulator II. Just trying to get any ideas other than just plug it in and go for it. Thanks! Aron
2010-09-30 by Susie
The electrolytic capacitors in the PSU (amongst others) are likely to be dried out, and as you are going to have to replace them anyway that's the first thing I'd do before powering on. I've seen other advice about using a variac to slowly bring the voltage up over a period of hours to allow the caps to reform, but I don't think caps ever reform to their previous new state. I cheap tip I picked up from repairing old valve/tube gear is to do the first power up with a 100W incandescent lightbulb wired in series with the mains supply - you can knock a socket and plug arrangement up really cheaply, possibly with bits you already have. The lightbulb acts like a current limiter and even if there's a direct short somewhere, the unit can't draw more current than would naturally flow through the bulb ~ 0.4A here in the UK. I'm not sure if that's really necessary with 'modern' (30 years old) gear though, but it gave me a bit of extra confidence with the 1950s Jennings Univox I brought back to life. If the lightbulb glows brightly then there's something very wrong, but you hopefully haven't done any damage. If it's healthy though, as was the case with the Univox, the lightbulb won't light, although of course it doesn't follow that an unlit lightbulb means you have a healthy synth - it's all about confidence levels. Cheers Susie http://www.myspace.com/susangardener --- In vintagesynthrepair@yahoogroups.com, "stompboxaron" <mylists@...> wrote:
> > Any tips on how to minimize any damage when turning on a vintage synth after 25+ years? One is a Prophet 5 and the other an Emulator II. > > Just trying to get any ideas other than just plug it in and go for it. > > Thanks! > > Aron >
2010-09-30 by grantbt@jps.net
-----Original Message-----
From: Susie
Sent: Sep 30, 2010 7:23 AM
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Re: Turning a vintage synth on after 30 years
�The electrolytic capacitors in the PSU (amongst others) are likely to be dried out, and as you are going to have to replace them anyway that's the first thing I'd do before powering on.
I've seen other advice about using a variac to slowly bring the voltage up over a period of hours to allow the caps to reform, but I don't think caps ever reform to their previous new state.
I cheap tip I picked up from repairing old valve/tube gear is to do the first power up with a 100W incandescent lightbulb wired in series with the mains supply - you can knock a socket and plug arrangement up really cheaply, possibly with bits you already have. The lightbulb acts like a current limiter and even if there's a direct short somewhere, the unit can't draw more current than would naturally flow through the bulb ~ 0.4A here in the UK. I'm not sure if that's really necessary with 'modern' (30 years old) gear though, but it gave me a bit of extra confidence with the 1950s Jennings Univox I brought back to life. If the lightbulb glows brightly then there's something very wrong, but you hopefully haven't done any damage. If it's healthy though, as was the case with the Univox, the lightbulb won't light, although of course it doesn't follow that an unlit lightbulb means you have a healthy synth - it's all about confidence levels.
Cheers
Susie
http://www.myspace.com/susangardener
--- In vintagesynthrepair@...m, "stompboxaron" wrote:
>
> Any tips on how to minimize any damage when turning on a vintage synth after 25+ years? One is a Prophet 5 and the other an Emulator II.
>
> Just trying to get any ideas other than just plug it in and go for it.
>
> Thanks!
>
> Aron
>
2010-09-30 by klosmon
Having repaired around 300 Prophet 5s, I'll just say that the tantalum bypass caps (used on the power supply, CPU and voice boards) are the leading cause of failure in this synth. The first thing I always do is replace them with equal value high-temp electrolytics -- have been doing this for years with no problem. ~GMM
> > -----Original Message----- > From: Susie > Sent: Sep 30, 2010 7:23 AM > To: vintagesynthrepair@yahoogroups.com > Subject: [vintagesynthrepair] Re: Turning a vintage synth on after > 30 years > > > > The electrolytic capacitors in the PSU (amongst others) are likely > to be dried out, and as you are going to have to replace them > anyway that's the first thing I'd do before powering on. > > I've seen other advice about using a variac to slowly bring the > voltage up over a period of hours to allow the caps to reform, but > I don't think caps ever reform to their previous new state. > > I cheap tip I picked up from repairing old valve/tube gear is to > do the first power up with a 100W incandescent lightbulb wired in > series with the mains supply - you can knock a socket and plug > arrangement up really cheaply, possibly with bits you already > have. The lightbulb acts like a current limiter and even if > there's a direct short somewhere, the unit can't draw more current > than would naturally flow through the bulb ~ 0.4A here in the UK. > I'm not sure if that's really necessary with 'modern' (30 years > old) gear though, but it gave me a bit of extra confidence with > the 1950s Jennings Univox I brought back to life. If the lightbulb > glows brightly then there's something very wrong, but you > hopefully haven't done any damage. If it's healthy though, as was > the case with the Univox, the lightbulb won't light, although of > course it doesn't follow that an unlit lightbulb means you have a > healthy synth - it's all about confidence levels. > > Cheers > Susie > http://www.myspace.com/susangardener > > --- In vintagesynthrepair@yahoogroups.com > <mailto:vintagesynthrepair%40yahoogroups.com>, "stompboxaron" > <mylists@...> wrote: > > > > Any tips on how to minimize any damage when turning on a vintage > synth after 25+ years? One is a Prophet 5 and the other an > Emulator II. > > > > Just trying to get any ideas other than just plug it in and go > for it. > > > > Thanks! > > > > Aron > > > >
2010-10-01 by Quazimodo
I checked out your Myspace Susie and I like your tracks...;c) --- In vintagesynthrepair@yahoogroups.com, "Susie" <gardens@...> wrote:
> > Cheers > Susie > http://www.myspace.com/susangardener > >
2010-10-01 by Susie
Glad you like my music Quazimodo! Picking up on the tantalum caps comment. Yes, in my RS202, the dead notes were caused by dead tantalum caps. The electrolytics seemed OK. I guess every synth has its weak spots. The Univox had some old plastic bodied caps - they weren't the usual suspect electolytic or tantalum - maybe polyester? Every one of them was completely dead. --- In vintagesynthrepair@yahoogroups.com, "Quazimodo" <noddyspuncture@...> wrote:
> > I checked out your Myspace Susie and I like your tracks...;c) > > > > --- In vintagesynthrepair@yahoogroups.com, "Susie" <gardens@> wrote: > > > > Cheers > > Susie > > http://www.myspace.com/susangardener > > > > >