NeXT Computers

[Rob Blessin Black Hole]

Hello NeXT Community: I've noticed today in paticular that after replacing caps on motherboards , I'm getting memory failed errors and it will list a bank or an actual slot , saying it is a bad simm. I bought new ram as in manufactured new and when I test the same 4 simms in another board they work fine. My suspicion is either the actual simms slot being the culprit or an additional failed component. To make sure it is not the ram as in a bad run , I'm going to test it with my black box simm checker.
My question would be is there any recommendation to clean ram slots carefully, I've used dust off , what about deoxit!

Best Regards Rob Blessin
_________________
Rob Blessin President computerpowwow ebay sales@blackholeinc.com http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community since 2/9/93

[barcher174]

Yeah, contact cleaner should work. In my experience the cap next to the RAM slots can also leak underneath. That's difficult to safely clean. I use a specialty ultrasonic cleaner and solution to get at it. As for board level repairs, I have seen the buffer chips go bad on a few (Those need to be harvested from other boards, I know of no source). The sockets can also be replaced in more extreme cases.

[Rob Blessin Black Hole]

Hello NeXT Community: I found this very useful document in identifying early 30 pin and 72 pin simms https://www.techsupportalert.com/pdf/h0831.pdf and as a follow up , when checking the "new" Ram" they had manufactured for me , they used a variety of chips on the 30 pin simms IBM, Mitsubishi , Vtech and another unidentifyable in the run.... so if I mixed sets of 4 this caused problems and running them through my black box simm checker also produced errors , I had a 25% failure rate. I suspect what may have happened is they sent me through all of their dud rma returns lol at any rate. The offending simms have been removed and aligned and I've learned from the experience.
I'm going to place another order for simms with specs this time to insure more quality control . It drives me nuts the intermittent errors but I've learned patience.
_________________
Rob Blessin President computerpowwow ebay sales@blackholeinc.com http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community since 2/9/93