CA3179G

is

in the

Data including full die schematic in 1986 RCA databook

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

is

in the

CA3163 may be pin for pin the same but only up to 1000M

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Ebay #280197429772 CA3179P At least I think thats what hes selling! Some Italian babble about minimum order value but I don't see how you can do that on Ebay

Yep, have that (or equivalent):

Had to twist Google's arm to get that. :)

This is in reference to the Ramsey CT-125 frequency counter I asked about in another thread.

The CA3179G may be working fine but tends to oscillate if there is no or low input, or the input frequency is below about 2 MHz. Someone else with the same counter described a similar behavior so it may simply be normal for the chip, or the mediocre design and layout of the counter PCB.

But the sensitivity of the input is also way too low (requires about 1 V, spec calls for a few dozen mV), so this could be related to the prescaler, or to the input transistor, though that seems to work.

The CA3179G is socketed so it would be nice to be able to simply swap in another one to see if anything changes. (Yes, I know, a socketed part in a GHz circuit isn't the greatest, but the wet finger test doesn't turn up any obvious effects).

I have a directory with the Ramsey info including schematics (thanks to someone on this NG):

I don't guarantee this link will remain forever, so get'em while you can!

Thanks.

--- sam | Sci.Electronics.Repair FAQ:

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DIP.

low

is

in the

Can you be sure the socket is original?

Datasheet shows Smith chart and (quasi?) microstrip layout and certainly no socket. How about removing the socket and minimally soldering IC to board and see what happens.

3 pins are n/c anyway

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

I know. I'm a bit impressed that it works at all on a normal PCB with mediocre layout and minimial bypassing.

There are a lot of things that probably should be done.

Thanks.

--- sam | Sci.Electronics.Repair FAQ:

Repair | Main Table of Contents:

+Lasers | Sam's Laser FAQ: | Mirror Sites:

Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.