[sdiy] anyone know what this chip is? M334 7161

[Roy J. Tellason]

On Wednesday 15 April 2009 11:18:11 pm Loscha wrote:
> Afternoon Ladies and Gentlemens.
>
> Please consider the following images:
>   http://www.loscha.com/images/M334-7161.jpg  155k
>   http://www.loscha.com/images/M334-7161_small.jpg  20k
>
>
> There are two of these in a thing called an Orgatron (GTR orgatron 2,
> from the late 60s-ish, an electronic thing, not the electroacoustic
> reed organ thingy).

Orgatron was also a name used for some models by (I think?) Baldwin Organs...

> It was posted about when I first got it on Matrixsynth. Apparantly my
> kid sister is a "Synth Babe". That page it links to is 404, by the
> way, I don't think I have the sample up online anymore. It sounded
> quite crap. A mono square osciallator with a few switched cap static
> filters as "stops".
> http://matrixsynth.blogspot.com/2006/11/gtr-orgatron.html
>
>  Has anyone seen this part before? 

Yes,  there were a number of parts like that,  in similar packages,  made by 
Motorola for a while.  Their prefix was MFC or MCF or similar,  I can't 
recall exactly at the moment.  Philips ECG used to list substitutes for them 
but they were discontinued in the last books I have for them.  Part numbers 
were around ECG770,  ECG775,  and similar.

> The unit has some stops that are octave down, so, thinking it may be a
> divider. Seems like an "organy" type chip, I recall seeing something similar
> in a Crumar organ/piano I had 10 years ago.

I believe it's just a flip-flop in that package,  though I'd have to do some 
digging to find out exactly for sure.  What data I've been able to get into 
my hands just now shows me similar parts with 6 or 8 pins,  some of them dual 
flip-flops,  and from the diagrams they're showing of the insides of the part 
probably RTL.

> Any assistance would be appreciated. Hoping, honestly, that they'll be
> able to be given to someone to repair something worth while, instead
> of this piece of crap I junked & dumped today!!!!!
>
> They are both connected up in a similar fashion.
> Short pin next to trace (the lump) always goes to earth.
> Long pin not on bump end goes to +ve

What power supply voltage were they running them at?

> They are situated in the section of the circuit which is a volume
> control. Possibly some kind of VCA or amplifying transistor.
>
> It's not in my little "cubic" Tech/Eca Asia Pacigic "Up-To-Date
> World's Transistors-Diodes-Thyristors & ICs Comparison Tables". (the
> Jaycar ones, about 10 years old).
> I'm stumped. Am not even sure what package to call it.

It's a pretty unique package all right,  I don't think that anything else used 
that style of packaging.

>  Thanks for your time if you bothered to read my rambling all the same!

You'll have two other signals there,  signal (clock) input,  and a 
divided-by-2 output.  It might be possible to rig something with perhaps a 
CMOS chip on a bit of perfboard,  maybe?

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