Just wondering if anyone had run into this and/or had an opinion.

Had an issue on a TZ with 'garbage' dots on the display, run the diags and get "RAM Test Failed".

OK, simple enough. Go the the manual and the part is called out as a S/RAM 2064 150NS. Order a couple of the chips and once they arrive I pull the old chip, install a good quality IC socket, (never want to repeat surgery at the same place on a PCB if it can be avoided) and install the new chip.

Put the board back in the machine and light it up. Yay! No 'garbage' dots and the diags pass. However I notice a new oddity after a few games. Now there is 'snow' on the display when it is actively being updated. Random flurries of half lit dots but only when the display is being updated. If the display is static, all is well. Do not recall seeing this before.

This to me feels like an access speed issue with the S/RAM. The parts I ordered were not some odd 'off-brand', so I am wondering if perhaps the speed indicated in the manual is incorrect? Maybe should have been a 100NS (or 120NS) part? Granted, I could have gotten one out of spec (slow) part but if I swap it out with the other from the order the 'snow' is still there.

Trying not to believe that I got Murphy'd on both chips... Figured it would be worth the ask before I ordered some faster parts.

Thoughts?

Nope... In my case the image on the display is correct at all times but the flickering dots ('snow') are seen randomly around the screen when the display is being updated. (score change, animation, etc...)

When the display is not actively changing the 'snow' vanishes.