C4040 ?

[Marcin]

I have bought a mystery chip. I'm not sure if that is C4040 because prints were totally wiped off. Someone have a hardware to test it ?

[CPUShack]

I think doccybrown does or did

If not I do

[lither]

[Marcin]

@Lither
Looks like a easy method to check I will let you know about results.

@CPUShack
Thanks. I will try lither's method first

[kosmokrator]

yes looks promissing about c4040....but maybe a just early rom ....
test it ....

[naked1300]

...open the die core and i can check it with my microscope *lol*

[Marcin]

[johnorun]

I have a Fluke 1953A Counter Timer that has a P4040 in a socket and it's working OK.
If you still want to test it let me know...

[doccybrown]

You can check it on your own by simply using a multimeter in
diode-test mode without damaging any testing hardware (and the chip)!
Check the pins for their breakdown voltages with
voltage source and drain-pins of the chip (first Vss and then Vdd-pins to
all remaining pins). If really a 4040 you will notice at least
that data/adress-bus pins and CMs have characteristical values
exactly where the pinout says there is something like that -
the same is for the status- and control-pins.

[Marcin]

Thanks Doccy. It looks like it is not C4040 :-/ I must search for C4008 pinout to be sure.

[grimm]

That almost looks exactly like some of my chips here (take a look at the second picture):

http://www.cpu-world.com/forum/viewtopic.php?t=15039

I'm pretty sure that mine are chips made by NCR but I don't know anything about them. Also mine do not have any printing on the bottom, just the tops.