IC Identification NEC 551E3Y1A - maybe?

[fdk]

Hi all,

I've been trying to find out what this IC is for a while now, it is inside a Yashica Electro 35 FC.  I had someone suggest that it was a transistor package, based on some info for a different model, but I don't know if I fully agree with that.  There are 3 other silicone transistors elsewhere, which I think are the replacement to earlier transistors (Germanium?) from earlier models.

If you look at the photo, it is a 10p DIP with only 6 pins connected.

https://i.ibb.co/SNHpf58/IMG-20221204-000438.jpg

Date is around late 60's early 70's.  Probably 71 or 72 this model camera was updated, probably to the Gx series.

I'm not really sure of the purpose of this IC, but I suspect it is something to do with the light sensor which lights up 2 different arrows to indicate either under or overexposure.  A datasheet would probably give a clue but I have found nothing so far.  Camera is currently overseas, so I can't do any testing, though I am semi inclined to buy another just to try and figure it out! 

The real reason I had it apart was to see if it was possible to fit a small rechargeable battery in place of the original mercury containing batteries (it is).

So I hoping someone might have a clue what this IC is, and perhaps a datasheet that can help figure out if it is working or not.  Thanks!

[fzabkar]

It doesn't help, but the part number prefix is probably "uPC".

µPA : Twin Transistor and Miscellaneous Device
µPB : Monolithic Bipolar Digital
µPC : Monolithic Linear
µPD : Monolithic MOS

I had a cursory look here, but I couldn't find anything:

https://mirrorservice.org/sites/www.bitsavers.org/components/nec/_dataBooks/

[fdk]

Thanks very much for the link, I had bee looking for some kind of catalogue but couldn't find anything.  It doesn't help there is an NEC TV or monitor with model number 551..I'll dig through an see if I can find anything.

[amyk]

uPC55 is an op-amp, which seems close to the purpose of your part. Given the date, I suspect whatever documentation exists on it is likely to be in Japanese only.

[Shonky]

This manual has some schematics. Does this line up with the board?

https://www.manualslib.com/manual/1174739/Yashica-Electro-35.html

[fdk]

That one is a different, maybe earlier, model.  There are enough differences to think it's not as simple as substituting one part for another.  As amyk suggested, my thoughts were maybe an opamp of some sort, but I don't know how test that theory.