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Subject: Re: [korgpolyex] Waveforms around the M5232 chip

From: Marcus Wilson <JB@...>
Date: 2006-06-08

when you turn it on do you get a readout on the 7 segment displays?

11 P

are you able to check that it sends and receives midi?

have you made sure that you have loaded in patches to ensure that there is actually a waveform for the tg to create?

have you checked for output at the headphones AND the L-R outputs?

I had a poly that for a long time I thought was a dead TG, but ended up being a dead headphone op amp

in the end I was able to fix that problem as well, however the above sequence would help in tracing the issue

best regards,

Marcus
On 08/06/2006, at 4:24 AM, mark_r_abcd wrote:

Hi all,

I'm trying to get an MK1 Poly 800 back to life. I suspect that the tone
generator chip (IC3) is faulty.

The clocks to pins 19 and 20 look OK, and the envelope inputs E0-E7
rise and fall as expected when I press keys. The power supply pins look
OK too, and the data, address, ALE and ~WR are all clocking nicely.
However, there's nothing much on the footage outputs. They're all more
or less stuck at +5V, although there's a little square wave wobble on
some of them whose amplitude tracks the envelope input.

Is it likely that my TG is busted, or am I missing something else?

Cheers

mark-r