In article , N Cook wrote:
Mark Zenier wrote in message
...
In article ,
toomanytoys wrote:
Does anyone have Datasheet or the pinouts for an AY1-5051 Fixed Modulus
Divider chip? I can't find them on the internet. It was made by General
Instruments (later Arizona Microchip) and is a PMOS technology.

I am trying to repair a 1960's Elka organ for an 82 year old friend. He
has
had it
since nearly new and it has been reliable until now. He would rather
repair
than
replace.

Fresh off the scanner, all two pages of it. (about 50k bytes).

ftp://ftp.eskimo.com/u/m/mzenier/AY-1-5050.pdf

Includes AY-1-5050 AY-1-5051 AY-1-6721/5 AY-1-6721/6


Thats tidied up the mystery of the graphics only sheet I have from GI as
only the 5050 was labelled as such.

The next problem is how to buffer the outputs of a 4024, or something, to
drive 30V chippery? a 4104 is not high enough , 7x discrete SM ?

So to the OP - what are the next devices in the chain being driven by each
octave from the ay1-5051 ?
^
Note: You guys might have better luck adding in the extra "-" in the
part number for your searches.

Did you see the fine print about the two power supplies. The outputs
are fed seperatly from VDD, which only goes to -13 volts. And that
VDD can be modulated for various effects. Using the numbers in the
"Drive capablity" section of the characteristics, it looks like the
output is a Fet pulldown with a 6k ohm load.

Here's how I would do a workalike.

Power supply. You have to use the -27 volt VGG since VDD can be
modulated. So a 12 volt or thereabouts zener, and a series resistor
should be ok to get a -12 volt supply. Which will feed some CD4000
family chips, running upside down. Their positive power supply being
the PMOS ground. Typical drain for the old chip is 3 milliamps, that
should be plenty for a handful of CMOS logic running at audio frequencies.

For each input, an input resistor, diode clamps to the CMOS power positive
(gnd) and negative supply, and a schmitt trigger buffer or inverter.
CD40106? Then use either D latches (4013) or JK ff's (4027) for the
dividers. Easier to get the short divider chains than the CD4024 if
you don't know how the external circuit is wired. If which edge is the
trigger matters, you may needed to chain one of the spare 40106 inverters
to get the right polarity to feed the flip flop.

For each output, a small p channel MOSFET, source to (PMOS) ground,
with a 6.2k ohm drain resistor to VDD. (Or maybe a jellybean PNP with a
base resistor. Depends on the sound that results, perhaps). You might
need a capacitor or RC filter across the output to slow down the edges.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)