Tks for help on capacitors all replaced.
Next problem. If I have all 8 slots filled for my memory stick i get a error in slot 1. If i just fill the first four there is no error. If I swap memory there is no problem... The first message error is a coupling dependent failure. What is funny is with all 8 slots filled it sees 8 meg. Oh I don't know if this means anything but powering down ends up with a reboot
This is going to be a tough one. First thing is to check for any rotted traces on the board or any pins for the RAM slots shorting together. Based on previous experience it's possible one of the SC63594FN buffers is bad. Unfortunately I know of no source for replacements outside of dead boards (I can't even find a datasheet for them).
Maybe barcher174 has seen this scenario and is right on track. For me you are not providing enough info to help you.
Which size do the SIMMs have?
What do you mean with "If I swap memory there is no problem"?
Have you tried other SIMMs?
You could try the NeXT Service Diagnostics tool (dvt040). It has a memory test and might give you more info.
HTH,
bobo68
When I boot I get error at 50403c4...value at time of failure 6db6dbec...main coupling memory failure one or more sims in bank 1 is bad...bank 0 is the first bank.... main memory test failure
I have 8 1 gig chips. IF I put just four in no error shows up I have swapped the four around and still no problem.... As soon as i put the eight in then the error comes, but it recognizes the 8 gig of memory. I am able to boot to my scsi drive through even with those messages. I will try the suggested memory test...
tks
Quote from: "jmeddo"When I boot I get error at 50403c4...value at time of failure 6db6dbec...main coupling memory failure one or more sims in bank 1 is bad...bank 0 is the first bank.... main memory test failure
I have 8 1 gig chips. IF I put just four in no error shows up I have swapped the four around and still no problem.... As soon as i put the eight in then the error comes, but it recognizes the 8 gig of memory. I am able to boot to my scsi drive through even with those messages. I will try the suggested memory test...
tks
you should also take a look at your boot ROM. AFAIK they had done something in case of memory timing in later versions.
Quote from: "jmeddo"I will try the suggested memory test...tks
Good, you can find the test software here:
http://www.nextcomputers.org/NeXTfiles/Software/Diagnostic_Utilities/. The dvt040 dignostic programm can be found in 68040.tar.gz. Throw dvt040 in the root directory of the boot drive and boot with "bsd dvt040" from the ROM monitor. Let us know what you find out.
You could also try to play with RAM parity checking in the ROM monitor.
Having the latest ROM (in your case 2.5 v66) is always a good idea.
HTH
bobo68
Here is the NeXT Factory manual...
http://www.blackholeinc.com/docs/NeXTServiceManualPages1-160_OCR.pdfpages 32 through 40 is what you need!
Best Regards Rob Blessin
I have plenty of memory both used 1Mb for $1 each set of 4 = $4 and new Ram 4 * 4Mb =16Mb simms for $32 max 32Mb = $64 and yes tested they work. or Used 4Mb simms at $1 Mb sets of 4 = $16
I can also burn NeXT Rom Chips $15
Heck if you email a photo of the ram , I'll give you a matching 1mb for free just pay shipping guesing about $7 priority mail or $3.50 first class as I would like to see you up and running.
best Regards Rob