Please try hooking up a battery first.

If there's no change in behavior, swap the 5101 for a genuine from another board.

Look at the date codes and if they look "new".
Real Philips PCD5101P have a white stripe across the top of the chip and they're printed in white, not etched. See here - the bottom line shows a date code of '91

PCD5101P (resized).jpg

So three of those counterfeits failed on three different boards?

I'm finding parts coming from China are not being remarked as much any more and often come scratched up now but at least you know what they really are.

I've bought genuine 5101 from here in the past each having original markings with different date codes from the early 90's. BUT, beware they often come with shorter legs.
Problem now is they'll probably take 2-3 months to arrive.

https://www.aliexpress.com/item/32623218514.html

I wonder if its a really slow 5101 marked as a PCD5101P. Still can pass the POST but not keep up in normal operation? A couple times I have had bad 5101 yet the game still booted. Would get weird things like the display digits shifted over to the left.

I still have some tubes of original imprint PCD5101P used socket pulls with full length legs I will probably never use because of NVRAM. Random date codes from 80s and 90s. I tested every single one with a neoloch back years ago when I bought them. $2 ea + ship.

Now I'm getting worried. I just bought some 5101's from Ebay:

ebay.com link: 1 PHILIPS PCD5101P 256 x 4 BIT STATIC RAM 22 PIN PDIP VINTAGE PINBALL SRAM IC

Looked too good to be true. I'm guessing they're fake. I'm afraid to use them now.

IMG_4858 (resized).JPG

IMG_4864 (resized).JPG

Would the Neoloch tester weed out any bad 5101's that boot but don't preform correctly? I have a PIA blade but maybe I should get the SRAM blade.

I see David sold Neoloch to Pinball Classics. I don't think I've bought from them. They're not related to Classic Arcade are they?

Hi Bob, I don't have any date codes as old as your picture, but I think those pictured are likely genuine PCD5101P.

The ones I have mostly have the phillips logo on the vertical bar on the left side like Quench's picture.

Somewhere between 1987 and 1990 the Phillips logo started appearing on pcd5101p.

20200624_214759 (resized).jpg

Glad to hear everything got sorted out. I may have missed something above but out of curiosity, the OP mentioned swapping in known good boards (2 I believe?) one of which was working in another machine.

Did those boards also not work because they had questionable RAM too? If so, how is it that the boards would work in another machine?

I also wonder if they're maybe remarked 2101 chips (pin/memory compatible but higher power version). Although the circle divots look like originals.
Jethros chips have a date code of the year '50 - the Chinese really screwed that up

I think yours are originals from '84 - Philips probably marked them different at the time, plus they are shiny black. All the Chinese remark chips I get are coated or shaved and look matt black.

This is the question..

That's what worries me most. When I repair a board for someone I always bench test it but without the game I don't really know if it's going to work.

These Ebay chips look brand new with a '84 date code. Hard to believe they're 35 years old and never used. I would have felt better if they were scuffed up.

Buying from a surplus store I'd expect them to be NOS parts. They even had the original box pictured that they came in.

Didn't I read in another thread you have a Meteor with you? You can test two 5101 chips at the same time in that game.

You believe they are 35 year old NOS. I also have a MPU 200 coming. I might try the new board with these RAMs in the Meteor.

Thanks Quench.

Why isn't this thread marked resolved?

Why not just move to 5101 NVRAM to make these old Bally games battery free? IC sockets are already on the board, so it seems like a no-brainer to me.