When I first started working on computer we had a dram tester. Simple little box with a button for testing and a knob for speed. Lock in the chip to set the speed and hit the buttons. Simple red / green light tells if it passed or not. I found out by pushing the speed up a tad more. It weeded out bad or questionable chips. Luckly this was at the time dram was cheap due to being replaced with simms. I'm looking around just in case I need one to trouble shoot the ram in my Apple II+ When I get it. I found this on e-bay.
Commodore 64 (and more) memory chip tester - 4164/41256 DRAM
https://www.ebay.com/itm/Commodore-64-and-more-memory-chip-tester-4164-41256-DRAM/283430014054?hash=item41fdbecc66:g:W84AAOSw0n5c2Ce0
Thanks,
Josh
take a look at http://forum.defence-force.org/viewtopic.php?t=1699
ciao
This Arduino nano gives a very low testing speed. Looking at the source code, this test setup also uses native functions for I/O. At most you get a few tens of kHz output frequency as you have several pins to manipulate. As can be seen here, replacing the native function with faster ones would improve it, but not by much (taking more than 1us per pin).
The DRAM datasheet (TMS4164 ) shows that there is no maximum delay between different pulses, so in theory it may work. But you would not be straining the chip to test it properly, meaning that even if it passes testing at slower speed, it may not work at higher speeds.
I've had very good luck with the neoloch static ram and dynamic ram tester and used it for several years to test hundreds of different ram chips on the various 8 bit systems I've restored. It has been reliable at finding not only outright bad ram but also marginal chips. A bit more expensive, but has been worth it to me at cutting down the debugging time and testing replacement ram bought from various sources as well before installation/use. They also have a blade for testing PIA and RIOT I/O chips. Happy user - no connection with the company.
Link: http://www.neoloch.com/products/Inquisitor.php