McIntosh MR77 tuner - IC needed for MPX board

[mjatabor]

I have a 1972 McIntosh MR77 tuner.

I broke off 2 pins (#1, #14 I think) on the Motorola 14 pin IC on the MPX circuit board while I was giving it a thorough cleaning. (Please don't scold me for my ignorance...I feel bad about it)

It is IC 301 on their technical manual (part #133-004) located on the MPX circuit board in the rear left of the tuner.
Does someone know what IC this is? (Attached is a photo of it)

I can buy it for $40+$8 shipping from Mac. I want to see if I can get it cheaper, especially since I can't afford to have it aligned either (it only picks up 6 strong stations).
A member of another forum said it is 'comercial number motorola mc1303' integrated circuit. I see there are various versions of this IC and maybe there are better substitutes too.

Humbly,

[AuroraB]

No ideas for source or subsitutes, but if you are reasonably skilled at soldering, you can easily do some electronic first aid...
snip two pins off another donor IC and solder them to that chip.....
put the IC in it's socket(?), set the two missing pins and give them a SMALL blob of solder - wait at least 10 sec's between the the two joints....

[mjatabor]

It did cross my mind to solder two pins on to the IC. So you recommend putting the missing pins and the IC in the socket, then solder in place? I was thinking of doing it upside down on a counter.

[AuroraB]

If you can manage to make them stick correctly, solder outside the socket.
If you solder with the IC and pin in the socket , work quickly but properly ,- meaning: do not overheat or use excessive solder...... done it a few times some years ago....

[stellavox]

I'm guessing that the chip may be a MC1309.

Data sheet here:
MC1310 Datasheet PDF,MC1310 Circuit,MC1310 Manual - Soiseek

See if the pin functions appear to line up. Would probably be hard to find now. There were a few more multiplex decoder chips made - which may actually have an identical - or close pin layout. Do a search under multiplex decoder IC's and see what you find - then good luck in sourcing the part.

Charles

[rayfutrell]

My 1979 Motorola linear ic databook has the MC1310 as the standard stereo demodulator. NTE makes a replacement.
Ray

http://nte01.nteinc.com/nte%5CNTExRefSemiProd.nsf/$all/6BE0CF16669514578525791000819E2E?OpenDocument

[Kay Pirinha]

Hi,

if your pic shows your problem, i'd follow AuroaB's advice instead of looking for a substitute or replacement IC. You don't even need a 'donor IC', just solder two short pieces of thin wire to the remainders of the broken pins. There's pretty enough area to do so.

Good luck!

[Mooly]

I see mention of sockets... if the IC were in a socket originally then I would remove it and solder direct to the PCB. Just use a resistor leg soldered in to the pcb and it will pass up alongside the missing legs where it can be soldered. Snip to length when soldered and you wont even see it. Or use thin wire.

Have to ask how on earth did you break the legs cleaning a populated board.

[mjatabor]

Thanks for all the help. I'm a little nervous and not as knowledgeable as you folks. Are any of these IC recommendations a direct replacement or improvement, and I should not worry if I use a MC1303, MC1309, or MC1303. Will I cause harm if I put the incorrect IC in?

[mjatabor]

Originally Posted by Kay Pirinha

Hi,

if your pic shows your problem, i'd follow AuroaB's advice instead of looking for a substitute or replacement IC. You don't even need a 'donor IC', just solder two short pieces of thin wire to the remainders of the broken pins. There's pretty enough area to do so.

Good luck!

That seems simple enough for me. Should I look for a piece of copper solid wire that will hold in the socket firmly and flatten it with pliers to shape?
Also does the red dot on the IC indicate pin #1 so I can position correctly?