RAM Chip type in 128K

[stevep]

I have a 128K giving an error code indicating a bad memory chip. Does anyone know what the chip type or equivalent is? Are they available anywhere? Thanks!

 

[tomlee59]

These are 4164 DRAMs. That's a 64kbit (bit, not byte) by 1 chip. These have not been made in a longgggg time. You can find them, however, on old PCs (the very first generation of IBM 8088-based PCs, for example), among other bits of ancient trash.

Be advised that the error codes are not reliable. The boot routine doesn't do a very sophisticated test. It just writes a pattern, and expects to see it come back. Any discrepancy is flagged as a memory chip problem, but it could be a lot of other things, too. You should do a careful visual inspection of the chip in question, as well as of things connected to it. You might get lucky and find that it's just a bad solder joint, or a bit of crud that's fallen on some data lines, or a capacitor that's leaked its conductive guts on some trace.

 

[stevep]

These are 4164 DRAMs. That's a 64kbit (bit, not byte) by 1 chip. These have not been made in a longgggg time. You can find them, however, on old PCs (the very first generation of IBM 8088-based PCs, for example), among other bits of ancient trash.
Be advised that the error codes are not reliable. The boot routine doesn't do a very sophisticated test. It just writes a pattern, and expects to see it come back. Any discrepancy is flagged as a memory chip problem, but it could be a lot of other things, too. You should do a careful visual inspection of the chip in question, as well as of things connected to it. You might get lucky and find that it's just a bad solder joint, or a bit of crud that's fallen on some data lines, or a capacitor that's leaked its conductive guts on some trace.

Thanks for the help! I'll post a followup once I've opened the case and had a look. Would and IBM Pcjr have these chips? i have an old one of those lying out in the garage

 

[redrouteone]

If you do have a bad memory chip, might not be a bad time to upgrade the memory.

 

[tomlee59]

I haven't opened up a PCjr in ages, and don't remember what they had inside. But that's the right vintage, so it might be a source for these chips.

And if you do decide to upgrade to 512K, post back. I have complete directions on how to do it. It involves a non-negligible amount of surgery, and also changes your 128K into a non-stock machine, though, so I don't recommend it.

 

[stevep]

I haven't opened up a PCjr in ages, and don't remember what they had inside. But that's the right vintage, so it might be a source for these chips.
And if you do decide to upgrade to 512K, post back. I have complete directions on how to do it. It involves a non-negligible amount of surgery, and also changes your 128K into a non-stock machine, though, so I don't recommend it.

It will be staying a 128K. I like to keep them as they were made and I have a real 512K too.