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