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Re: where to find parts to replace Q1 and Q18? bringing dead polys back to life!

2007-11-20 by Jon

It went up in smoke.

I changed Q1 and Q18. Checked the pin-out - and I'm sure i got it right. (Otherwise Q1 
and Q18 would have been hot - and they weren't).

Anyway - what happened when I plugged in the power was that KD4 (the small 
transformer in the -5V area) went up in smoke.

And that's kinda odd..?

So now I'm thinking of building a new powersupply for it. Since getting a new part for KD4 
(I think it's called T1 on the board, but I'm not sure) will be kinda hard..?
Any other suggestions?

Cheers!

//Jon

--- In korgpolyex@yahoogroups.com, Marcus Wilson <JB@...> wrote:
>
> Q1 and Q3 can be replaced by:
> BD140
> 
> http://www.dse.com.au/cgi-bin/dse.storefront/ 
> 4735dc390a33bb062740c0a87f9c06b4/Product/View/Z1444
> .85c ea
> 
> Q18 can be replaced by:
> BD139
> 
> http://www.dse.com.au/cgi-bin/dse.storefront/ 
> 4735dc390a33bb062740c0a87f9c06b4/Product/View/Z1443
> .85c ea
> 
> just be sure to ensure they are in the right way around!
> 
> I have had 3 polys with no powerup, and dirty looking transistors.
> 
> By replacing these 3 transistors I have been able to resurrect 3  
> polys so far!
> 
> this secret is now out, and good luck to all who wish to try to  
> repair a dead poly using this replacement method.
> 
> Once these are replaced you should be able to see 11 P on the display  
> of the poly, and re-load your patches.
> 
> Best Regards,
> 
> Marcus Wilson
> 
> 
> 
> On 10/11/2007, at 10:35 PM, korgpolyex800 wrote:
> 
> > Jon,
> >
> > I did a google search on "NTE185 replacement" and "NTE254 replacement"
> > and got plenty of hits where you can get those transistors.
> >
> > Let us know how you progress.
> >
> > Mike.
> >
> > --- In korgpolyex@yahoogroups.com, "Jon" <shonokij@> wrote:
> > >
> > > Hi!
> > >
> > > New to the group and proud owner of a broken Poly 800 MKII!
> > >
> > > The guy who owned it before me tried to restore it, with poor
> > results (I think his plan was to
> > > cover it with solder and pray it works afterwards.. it didn't!).
> > >
> > > I've cleaned his mess up. But I'm missing Q1 and Q18 looks kinda  
> > abused.
> > >
> > > Since Q1 - B744 is no longer in production. It's replaced by NTE185
> > - hard to get for me and
> > > expensive. And it's the same with Q18 - B794 replaced by NTE254.
> > >
> > > So I was wondering if you guys have any suggestions for other parts
> > i could exchange Q18
> > > and Q1 with?
> > >
> > > Thanks!
> > >
> > > //Jon
> > >
> >
> >
> >
>

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