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Electronics => Beginners => Topic started by: retiredfeline on November 17, 2023, 09:41:10 am

Title: help identify this 8-pin DIP chip from Signetics
Post by: retiredfeline on November 17, 2023, 09:41:10 am

Standard black epoxy 8-pin DIP chip. The markings on it:

(Signetics logo) 7624
7002

That's it. I'd post a picture, but really there is nothing more to see. I assume the 7624 is a date code, although it could be the other way around. Anyway no hits on 7624 or 7002.

I extracted it from a small analog board that I acquired I don't remember how. Other chips on the board are a bunch of LM741s. There are a few TO-92 transistors, and one 7808 TO-92 regulator. Lots of axial carbon film resistors and electrolytic capacitors. No company name on the fibreglass single-layer board, just a board ID. Looks like the tracks were laid out with tape and then transferred to resist photographically. Probably a small run board.

I'm not trying to restore the board or even find out what it does. In fact I will be tossing it into the recycling bin soon. I'm just curious about the chip. Thanks.

Edit: Ok here are pictures of the front and back of the mystery PCB. I've removed the transistors and a trim pot. The position the 7002 chip used to occupy is the top right of the front and the top left of the back. Only 6 of the pins are connected. I'm guessing a special op-amp other than the 741, or a matched pair of transistors. The 77xx date codes on the 741s make it more likely 7624 is a date code so 7002 is the chip model.

I won't be doing any tracing on the circuit, it's not worth my time. It's unlikely the chip is worth reusing. I thought maybe somebody might recognise the chip number off-hand.

Title: Re: help identify this 8-pin DIP chip from Signetics
Post by: magic on November 17, 2023, 09:54:38 am

Could be a custom part number.

If no one has any quick answer, post pics of the board and/or try to trace the circuitry around the chip to get a clue about what it's doing.

Maybe another opamp if everything else is 741.

Title: Re: help identify this 8-pin DIP chip from Signetics
Post by: m k on November 17, 2023, 11:02:50 am

Maybe the one more sophisticated than 741.

Is 7808 a typical?
Maybe some of it is for offsetting 741 to 0V.

76 feels better for the year.

Title: Re: help identify this 8-pin DIP chip from Signetics
Post by: Terry Bites on November 18, 2023, 09:05:12 am

Do post a picture, it may reveal more to another pair of eyes.
Work out how it connects to the components around it. The function willl help ID it.
https://archive.org/search?query=signetics++dataBooks+