3
\$\begingroup\$

text on mystery IC

I found an old board in my stash which seems to be from a smoke detector. Trying to convert it into a doorbell I can hear way out in the yard. I tried Googling the numbers marked on the IC but I can't find anything. What I know so far is that the IC seems to be in a DIP-14 package, top is marked with a Motorola logo although the manufacturer prefix tend to indicate it is from Phillips. Pins 1, 3, 10, and 13 are not connected. Pin 2 is raised upwards as if there used to be another connection to another board at some point. Does anyone know what this IC is? A datasheet would help a lot. Thanks here is a top view of the board here is a bottom view of the board

\$\endgroup\$
  • \$\begingroup\$ The chip seems to be from 1978, so good luck... \$\endgroup\$ – Ale..chenski May 18 '19 at 20:11
  • \$\begingroup\$ And +1 for exemplary picture quality. \$\endgroup\$ – Ale..chenski May 18 '19 at 21:15
1
\$\begingroup\$

It's almost certainly a proprietary part, probably an application-specific smoke detector chip. The part number would either be dictated by the customer, or cooked up in cooperation between Motorola and the customer.

Smoke detectors are small, high-volume, and at least moderately high-tech; this is a combination that leads to ASICs.

For the purpose of making a loud noise, I suspect you want to look at the sounder and the transistor that's just below it in the component-side view. I suspect that the chip just applies power to that circuit, or possibly bias, or a square wave applied to the transistor base.

| improve this answer | |
\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.