Do you have questionable DRAM that you’re not sure is good or bad? This tester will help you sort through all that. You’ll quickly find out if any of your DRAM chips are bad.
The DRAM tester at its core, utilizes an ATMEGA328P with an Arduino boot loader which means the firmware is written in C.
The construction is such that the ATMEGA328P is socketed so it can be easily removed for firmware updates.
The coolest part about this tester has to be the OLED screen. This gives you a very nice read out of the testing progress. If the tester discovers that a chip is bad it will even display where it found the problem.
You can test both 4164 and 41256 DRAM. Simply move the jumper accordingly. 1 – 2 for 4164 and 2 – 3 for 41256.
The DRAM tester is assembled here in the US in Florida. I build these myself. They are not mass produced. Each tester is fully tested and carefully packaged before being shipped out.
Note: Please keep in mind that due to the speed limitations of the micro controller, in-depth tests that test the access time capability of DRAM are not possible. With that said, this tester does a great job at giving you 100% accuracy at detecting faulty DRAM. What this means is that if a DRAM is detected as bad then it is definitely bad but if it is detected as good, it could be a false positive and that particular memory chip may still have timing issues that would not have been discovered while testing.
A sign of good manners is to say who’s the original idea!
DIY Chris –
Of course, I don’t mind giving credit where credit is due. This design is based on your original idea.
The source is also freely available here https://git.fletchnet.xyz/cfletcher32/diy-chris-dram-tester
My apologies for not initially including this info.
John M Wettroth –
Very cool. There is nothing new under the sun. I designed a similar tester in 1990 for the first Circuit Cellar Design Contest in 1990. It won first price in the portable category. It tested functionality and access time for the 41xx DRAMs of the day. The complete schematic and source are available. If you can’t find a copy I can PM it.
Circuit Cellar Ink Issue 20 April/May 1991 Page 24
A Portable 8051‐Based DRAM Tester—Designing Maximum Features into Minimum Space, by John Wettroth