Hey everyone,
I'm glad this forum exists!
My poly800 just came up with this 1.8 50 01 screen...
cc0919ship could you tell me if replacing IC33 solved your problem?
I really don't want to sell it for parts... Hopefully it's just a chip that needs changing!
Please let me know
All the best
Silvere Letellier
--- In korgpolyex@yahoogroups.com, "cc0919ship" <cc0919@...> wrote:
>
> Tried everything, no dice...looks like it might be IC33. Ordering one now. Thanks
>
> --- In korgpolyex@yahoogroups.com, Michael Hawkins wrote:
> >
> > If swapping the DTC fixes the sequencer enable problem but then stops the "Step Up" from working (difficult to test if you don't have a pedal). Then you need to find a replacement DTC.
> >
> > If it doesn't fix the problem then you need to resolder all pins on IC33 and IC34. If that doesn't fix it then replace 74HC240 IC33 first. If that doesn't fix it then replace 74HC138 IC34.
> >
> > I've seen the 74HC240 fail a few times. I have not seen the 74HC138 fail.
> >
> >
> > Mike
> >
> >
> >
> > ________________________________
> > From: Michael Hawkins
> > To: "korgpolyex@yahoogroups.com"
> > Sent: Friday, January 25, 2013 6:59 PM
> > Subject: Re: [korgpolyex] Re: Frozen Poly 800
> >
> >
> > Â
> > I've seen the DTC's fail both on this forum and in working with some of my customers.
> >
> > So swap DTC4 for DTC5. DTC4 is used for the "Step up" jack. So you can swap it and see if you get anywhere.
> >
> > DTC stands for digital transistor something or other. They are essentially a transistor with a couple of bias resistors built into one package so that they act like a saturated transistor switch. There are DTC's out there now more commonly known as BRT's.
> >
> > http://www.onsemi.com/PowerSolutions/product.do?id=DTC144TM3
> > http://www.onsemi.com/PowerSolutions/parametrics.do?id=799
> >
> > Mike
> >
> >
> >
> >
> > ________________________________
> > From: cc0919ship
> > To: korgpolyex@yahoogroups.com
> > Sent: Thursday, January 24, 2013 10:38 PM
> > Subject: [korgpolyex] Re: Frozen Poly 800
> >
> >
> > Â
> > Sorry about all the posts, but it might be important to note that the display was the same even with the transistor removed
> >
> > --- In korgpolyex@yahoogroups.com, "cc0919ship" wrote:
> > >
> > > Hello all,
> > >
> > > I'm wondering if you can help me out. I recently acquired a broken Poly 800 (original, not MKII.) It powers up, but immediately after powering up, the screen reads "1.8 50 01." Buttons on the front panel do nothing, and keys do not make noise. If I turn up the volume the whole way, I can hear the filter sweeping up and down. Here's where it gets interesting - I plugged in a MIDI keyboard, and when I play notes with the MIDI keyboard, the 800 makes static noises, and the last value on the screen increments by one.
> > >
> > > I opened it up, checked the tactile switches (all seem fine.) I also replaced the internal CMOS battery. I was under the impression that MKI 800s didn't have this, so the main board may have been replaced by someone along the line.
> > >
> > > Anyway, has anyone had a problem like this and could help me out? It is potentially one of the ICs, but I have no idea how to test them.
> > >
> > > Thanks,
> > >
> > > Christian
> > >
> >
>