Korg Poly800/EX800 Users

I've checked it with the multimeter now and the pin 9 and 8 on the 
80C85 show 5v DC.. it doesn't respond to setting any parameters or 
the keys, just stays at this noisy sound after the initial 
filter/frequency sweep

any ideas?

Thanks!
jouni



--- In korgpolyex@yahoogroups.com, Michael Hawkins 
<korgpolyex800@...> wrote:
>
> If you have an oscilloscope or multimeter then download the 
schematics from our group web site and then check the test points 
that are shown on the schematic.
> 
> If you have an oscilloscope then you can check the waveforms 
precisely. If you only have a multimeter then looking for some 
voltage will do.
> 
> Disclaimer: Just be very careful poking around because you don't 
want to short anything out and do more damage than you already might 
have.
> 
> Regardless of the condition of the display chips, the display won't 
show anything at all if the RES6.5 clock is not running. So check for 
voltage on pin 9 of the 80C85. It should read a little above 0 volts.
> 
> Let us know what you find.
> 
> Mike.
> 
> dharmaone1977 <dharmaone1977@...> 
wrote:                                  I've got exactly the same 
problem!!!
>  
>  got my poly800 mkI 2nd hand, LED display/keys not working, the only
>  thing it gives  is a slow sweep from sub bass to high freq noise a 
few
>  secs after turning it on, then stays making noise until i turn it 
off.
>  chorus, filters and oscillators hence work.
>  
>  Any ideas?
>  
>  When powered the IC's all seem to have a voltage across them apart
>  from the LED IC. could it be a broken IC or (hopefully) something 
in
>  the +-5V power circuit not giving the board proper juice? the 
voltage
>  regulators maybe?
>  
>  It's not mkII so it doesn't have internal battery.
>  
>  No signs of leaked caps or cold solder joints or physical damage...
>  Tested with both batteries and 9V adapter
>  
>  THANKS!!
>  
>  Jouni
>  
>  --- In korgpolyex@yahoogroups.com, "Rob" <r.bowe@> wrote:
>  >
>  > Well, the Poly-800 I saved from the dumpster is not looking too 
good
>  > at the moment! The bad news is that it has no LED read-out of any
>  > kind, no flashing, nada. The good thing is, is that as I checked 
the
>  > V+ at the input I caught it dropping a few volts and suspected 
some
>  > kind of life! I proceeded to connect a set of phones to it and 
lo and
>  > behold, the unit gave me a real slow, but sweet pitch, amplitude
>  > and filter sweep, in stereo several seconds after start-up! It 
all
>  > swept up to a max and held. The only thing I can do to the sound 
is
>  > tune it with the slider and turn it up and down with the volume 
pot.
>  > Absolutely nothing else works. (I can affect the res. and cut-
off with
>  > VR's 2 & 3) So obviously the power, amp, filter and oscillator 
(not
>  > necessarily in that order!)sections are working fine. Is there a
>  > secret button combo or power-up trick that would re-initialize 
this
>  > thing or is the back-up and sysex "lost"? The lack of display is 
a
>  bother.
>  >  As you may remember from my previous post, I am a fairly 
effective
>  > bench tech and a damn good solderer and I read schematics fine, 
so
>  > even if there is something wrong at the component level, I 
shouldn't
>  > have any problems doing the fix, as long as someone out there 
has seen
>  > this problem before and knows the situation here. Aside from 
some one
>  > familiar with this glitch, it will be a stretch. Hopefully it 
won't be
>  > a big deal, so if you have an idea, I'll try to raise another 
Korg
>  > back from the dead! Otherwise, I have a really huge mono-patch, 
single
>  > sweep noise machine.
>  >  I am sure that's why I got this for nothing! But in the words of
>  > Monty Python...
>  >    "IT"S NOT DEAD YET!!"
>  >
>  
>  
>      
>                        
> 
>  
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