Discussion about the Korg PolySix synthesizer

Got the 367 board working!! (I decided to unsolder all my wires and start over and now it works!)
Thanks alot everyone. Now I need to tune  both machines and fix a dead vca along with some dead keys.. But I'm getting there:)
Thanks again. 

Sendt fra min iPhone

Den 18/05/2012 kl. 13.51 skrev "backshall1" <backshall1@bellsouth.net>:

> I would not assume the TC5514APL3 is bad. This is the memory chip and is
> unlikely to affect the switch functions. It is also quite a bit more
> expensive than the other chips. Without an oscilloscope or logic probe of
> some kind to find the source of the problem, you could be replacing a bunch
> of good chips trying to find the problem, only to find out that it was
> another bad trace on the circuit board, not a bad chip. Use only TC5514APL3
> to replace this if necessary.
> 
> The 1408 is the Digital to Analog converter, and also seems unlikely to be
> the problem. Any DAC08 type chip can probably be used here.
> 
> The 14042 used for IC28, 29, 34, 35 are a 4042 Quad Clocked D-latch, and are
> a prime suspect, although chances are the real problem is one of the D0-D7
> traces leading to these chips, not the chip itself. IC28 handles the octave
> and waveform, IC29 handles the subosc switch and sends the MG VCO/VCF/VCA
> control signal, IC34 handles Phase/Chorus etc. and IC35 handles VCA
> Attenuator.
> 
> Since you have multiple problems spanning all of these chips, it is unlikely
> that all 4042 chips are bad. More likely there is still a bad trace
> somewhere on the D0-D7 lines. If you are going to try to do this with only a
> Volt/Ohm meter, then turn the power off and measure resistance from CN10 to
> each of the connected chips for each of the D0-D7 signals. That’s a lot of
> work but a bad data signal on one of these traces is likely the only thing
> that could cause all of your problems.
> 
> Maybe it is time to invest in an old used oscilloscope. Since the clock
> speed on a Polysix is only 6Mhz and most signals are well below that speed,
> just about any old oscilloscope will work just fine. If you have an IPad or
> IPhone it might be possible to get a cheap oscilloscope app for them. You
> really need to be able to see what you are doing instead of working blind.
> 
> Don Backshall
> 
> _____ 
> 
> From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
> troels jørgensen
> Sent: Friday, May 18, 2012 6:51 AM
> To: PolySix@yahoogroups.com
> Subject: [PolySix] Replacement IC's
> 
> Yesterday i changed IC28 and IC 31 - as far as i can see these have to do
> with octave switch and waveform select (D00-D03) - and they still dont work
> (along with pwm etc).
> 
> If i follow the signal chain my next guess would be that either IC32
> (TC5514APL3) or IC33 (1408) is broken since they are the only ones that
> have to do with the broken parameters, and they are the only ones that are
> "after" what i have repaired in the signal chain.
> 
> -What would be good substitues for IC32 (TC5514) - IC 33 (1408) and IC 33
> (14042)?
> 
> Thanks again everyone!
> 
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> 


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