Service note.If Ic 34 (TCH40H138) fails then no sound will be heard for some or all groups of eight notes. So this would make believe as since it is in the service notes that this is a common flaw of this chip.
It is a toshiba chip. Ic 34 decodes all adresses for the cpu bus line supply.If this doesnt work you are doomed. If you need more info ill break out my parts box and stare at it. But I am unable to let such a valuble chip go man it took me weeks to find. I will look at the place I think I bought them at its a vintage chips sort of giant if they dont have it it dosent exist.I got as many as I could. Of Ic 33 and Ic 34 fail allot.If Ic 34 fail the one voice goes out in the cycle. These are outdated chips commonly made for other stuff.Happy hunting and good luck this is on page six of the schematic for poly 800 vers one repair same deal just added the delay section ...I assume no liabilty or malice this is a suggestion and any damage you do is on your own.
Happy trails
Alien
Marcus Wilson <JB@...> wrote:
sounds like an excellent start anyway!@
i have put my poly to one side at the moment, as i had no clue as to
where to proceed, this at least gives me a direction.
once again thank you for the info, hopefully it will bring one more
poly back to life!
thanks!
Marcus
On Monday, July 19, 2004, at 05:34 AM, x x wrote:
> Ok im looking up chip today you will have to find the chip on the net
> I dont think ill have one to spare. It wasnt easy locating the last
> set ...
> It sounds so like the main problem described in the tech notes up date
> that I fixed a poly with ....
> Will let you know today.
> Patrick
>
> Marcus Wilson wrote:
>
> awesome!~
> i'd be very keen to find out more.
>
> Mine was dead until i replaced a couple of power transistors in the +/-
> 5V stage that were buggered, and had been poorly messed with by a
> previous owner.
> I bought mine for $10 in a carpark junk sale, and took it home,
> managed to get the midi control side going so now i can control my
> other gear with the poly,
>
> all of the patches etc can be edited stored etc, and i managed to
> reload factory settings too, but no sound out.
>
> It looked like the clock and everything was performing properly but no
> tone out of the tone generator.
>
> Soldering is easy for me, so if you can point me to the correct
> component, i should be able to make it happy again, and that would be
> awesome!
>
> thanks again for your info so far.
>
> Marcus
> On Sunday, July 18, 2004, at 06:03 PM, x x wrote:
>
> > It is one toshiba chip that needs to be replaced.
> > It is mentioned in the service manual should all work but no sound be
> > heard from the poly 800. Its on the main board. The number of the
> chip
> > is on my schematics . I cant gurentee it but it is in the service
> > notes. apperntly enough of the same prob happend that this was a
> major
> > note. Im not saying this is or isnt .But Ive bought a few poly 800s
> > and its one or the other chips for the output control to the sound
> > source of the poly 800....
> > If interested Ill get the part number and email the service note. If
> > you can solder very finely its not a big chip. I dont know if I have
> a
> > spare im pretty much building up parts to keep for me when this
> > happens again. SinceI have three and I bought some extras let me see
> > what I find out when I look through my parts bin I collect toshiba
> > chips and major processors for the poly .Im now starting to with the
> > juno. I will sale poly 800 keys now and some other stuff .This will
> > also change I bid on every broken one I can find...
> > Peace
> > Alien
> >
> >
> > Marcus Wilson wrote:
> >
> > mines a poly800 yeah
> >
> > all works for midi control
> > no tone generation tho
> >
> > looking for a working tone generator for it
> >
> > Marcus
> > On Saturday, July 17, 2004, at 09:54 AM, x x wrote:
> >
> > > is that a poly 800?
> > >
> > > Marcus Wilson wrote:
> > >
> > > have you got any tone generator chips you could send me?
> > >
> > > my poly works on the digital side, all the patches store etc, midi
> > out
> > > works, just nothing comes out of the tone generator!
> > >
> > > ive put a cro over the data lines, and signals and clock all appear
> > to
> > > be working, just that chip has no output on the tone lines.
> > >
> > > any help available?
> > >
> > > best regards,
> > >
> > > Marcus in Oz
> > > On Saturday, July 17, 2004, at 06:45 AM, x x wrote:
> > >
> > > > I collect dead poly 800s////
> > > >
> > > > skunkride wrote:
> > > >
> > > >
> > > > Nice one Julio ! Gives me hope about my dead Poly....
> > > >
> > > >
> > > >
> > >
> > > >
> > > > Do you Yahoo!?
> > > > Yahoo! Mail - Helps protect you from nasty viruses.
> > >
> > > >
> > > > Yahoo! Groups Links
> > > >
> > > > � To visit your group on the web, go to:
> > > > http://groups.yahoo.com/group/korgpolyex/
> > > >
> > > > � To unsubscribe from this group, send an email to:
> > > > korgpolyex-unsubscribe@yahoogroups.com
> > > >
> > > > � Your use of Yahoo! Groups is subject to the Yahoo! Terms of
> > > Service.
> > > >
> > >
> > >
> > >
> >
> > >
> > > Do you Yahoo!?
> > > Vote for the stars of Yahoo!'s next ad campaign!
> >
> > >
> > >
> >
> > >
> > > Yahoo! Groups Links
> > >
> > > � To visit your group on the web, go to:
> > > http://groups.yahoo.com/group/korgpolyex/
> > >
> > > � To unsubscribe from this group, send an email to:
> > > korgpolyex-unsubscribe@yahoogroups.com
> > >
> > > � Your use of Yahoo! Groups is subject to the Yahoo! Terms of
> > Service.
> > >
> >
> >
> >
>
> >
> > Do you Yahoo!?
> > Vote for the stars of Yahoo!'s next ad campaign!
>
> >
> >
>
> >
> > Yahoo! Groups Links
> >
> > � To visit your group on the web, go to:
> > http://groups.yahoo.com/group/korgpolyex/
> >
> > � To unsubscribe from this group, send an email to:
> > korgpolyex-unsubscribe@yahoogroups.com
> >
> > � Your use of Yahoo! Groups is subject to the Yahoo! Terms of
> Service.
> >
>
>
>
>
> Do you Yahoo!?
> Vote for the stars of Yahoo!'s next ad campaign!
>
>
>
> Yahoo! Groups Links
>
> � To visit your group on the web, go to:
> http://groups.yahoo.com/group/korgpolyex/
>
> � To unsubscribe from this group, send an email to:
> korgpolyex-unsubscribe@yahoogroups.com
>
> � Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
>
Do you Yahoo!?
New and Improved Yahoo! Mail - Send 10MB messages!