Mac Pro RAM slot

littlecody8

macrumors member
Original poster
May 3, 2012
35
0
Just purchased a Mac Pro 1,1. I also purchased additional ram for it. Installed the ram and riser A isn't being recognized. I noticed the LED for cimm 2 is lit. I moved around all the dimms thinking maybe it was a bad stick but it's coming on for all of them. I switch the riser boards and it also does the same thing for the other board. I've done NVRAM reset (Cmd+Opt+P+R), nothing. Is there anything else I can try? Or do you think it's the actual riser board slot?
 

TheEasterBunny

macrumors 6502
Jan 22, 2013
251
0
Delaware
Just purchased a Mac Pro 1,1. I also purchased additional ram for it. Installed the ram and riser A isn't being recognized. I noticed the LED for cimm 2 is lit. I moved around all the dimms thinking maybe it was a bad stick but it's coming on for all of them. I switch the riser boards and it also does the same thing for the other board. I've done NVRAM reset (Cmd+Opt+P+R), nothing. Is there anything else I can try? Or do you think it's the actual riser board slot?
Search the stickies for installation procedure for Mac Pro's.
The RAM has to be installed in matching pairs. Make sure this is done right.
Try pulling out the riser cards and re-seating them.
Lastly, try cleaning out the riser card slots.
In this order.
If all of this does not solve the issue, run memtest. To see if you have a bad card.
Put in just two at a time.
Run test.
Repeat.
In the end you will find out where the issue is.
 

littlecody8

macrumors member
Original poster
May 3, 2012
35
0
I've done all that except for run memtest. I'll try that now.

The reason I'm thinking it's the slot is because BOTH riser boards have the same DIMM2 LED on when being used in slot A.

Is there a fix for the slot? That does not involve replacing an entire logic board or something....
 

brand

macrumors 601
Oct 3, 2006
4,363
395
127.0.0.1
Is there a fix for the slot? That does not involve replacing an entire logic board or something....
If you knew specifically what was wrong with the slot and had the technical skills to repair it then you could probably fix it. Since you are asking I am going to assume no to both.
 

TheEasterBunny

macrumors 6502
Jan 22, 2013
251
0
Delaware
Search the stickies for installation procedure for Mac Pro's.
The RAM has to be installed in matching pairs. Make sure this is done right.
Try pulling out the riser cards and re-seating them.
Lastly, try cleaning out the riser card slots.
In this order.
If all of this does not solve the issue, run memtest. To see if you have a bad card.
Put in just two at a time.
Run test.
Repeat.
In the end you will find out where the issue is.
The bold part, use a cardboard coaster with alcohol on it, then air blast.
 

littlecody8

macrumors member
Original poster
May 3, 2012
35
0
The bold part, use a cardboard coaster with alcohol on it, then air blast.
I was just using the can air spary before. Tried the alcohol and cardboard. Still no luck.
Memtest only tested the "installed" sticks. Which it's only showing the sticks on riser B as installed. Did them individually (paired on riser A slots 1+3) and they all work fine.

So I guess I'm stuck just using the four slots on riser B.


Would anyone be willing to trade eight 512mb sticks for four 1gb sticks by chance? ;) lol
 

DeltaMac

macrumors G3
Jul 30, 2003
9,588
2,349
Delaware
...
Memtest only tested the "installed" sticks. Which it's only showing the sticks on riser B as installed. Did them individually (paired on riser A slots 1+3) and they all work fine.
RAM pairs do not go in slots 1 & 3. One pair would be slot 1 & 2
One stick in slot 1, and one stick in slot 3 doesn't work.
Try a matched pair in 1 & 2, then in 3 & 4 (not sure if 3 & 4 only should work, but won't hurt to try, just to see if there is any change)

You said that you get a memory light next to slot 2 on the riser...
Does the front panel power LED flash in a repeating series of 3? or simply flash on & off?
And, finally, I'm not sure about what you say - that a memory riser in the lower slot (making it riser B) works, but not when you move the same memory riser in the top slot (making it riser A) - is that correct?
 

littlecody8

macrumors member
Original poster
May 3, 2012
35
0
RAM pairs do not go in slots 1 & 3. One pair would be slot 1 & 2
One stick in slot 1, and one stick in slot 3 doesn't work.
Try a matched pair in 1 & 2, then in 3 & 4 (not sure if 3 & 4 only should work, but won't hurt to try, just to see if there is any change)
Yes I understand it SHOULD be slot 1 and 2. Slot 2 does not work. Therefore whenever I use slot 1 and 2 it only uses slot 1. When I used slot 1 and 3 it worked as a pair. When trying to use riser B as well it does not show riser A, only B.

And, finally, I'm not sure about what you say - that a memory riser in the lower slot (making it riser B) works, but not when you move the same memory riser in the top slot (making it riser A) - is that correct?
Correct. No matter which of the two riser boards I am using as A, the dimm2 LED on the front of the board is lit.
 

TheEasterBunny

macrumors 6502
Jan 22, 2013
251
0
Delaware
Yes I understand it SHOULD be slot 1 and 2. Slot 2 does not work. Therefore whenever I use slot 1 and 2 it only uses slot 1. When I used slot 1 and 3 it worked as a pair. When trying to use riser B as well it does not show riser A, only B.



Correct. No matter which of the two riser boards I am using as A, the dimm2 LED on the front of the board is lit.
If I read all this right, and I'm not sure I did. You have determined that both risers are fine.
Have you run tests on all the sticks of RAM?
Did they test out ok?
BTW, when you have sticks in 1 and 3, they are NOT paired, however the Mac is seeing them, but not using them as pairs.
Also, The Mac can be booted and run using only one riser, not the ideal situation, but it will work.
It is sounding like there is some main board issue at play here, whether that is a bad/dirty slot, or a card edge that is not making good contact, or something more serious I don't know.
Main boards for this model cost more than it is worth unfortunately.
There is a reset button on the main board, this can be pressed for say 30 seconds and it may clear out the issue, but probably not, worth a try though.
 

DeltaMac

macrumors G3
Jul 30, 2003
9,588
2,349
Delaware
... You have determined that both risers are fine.
Have you run tests on all the sticks of RAM?
Did they test out ok?
BTW, when you have sticks in 1 and 3, they are NOT paired, however the Mac is seeing them, but not using them as pairs.

It is sounding like there is some main board issue at play here, whether that is a bad/dirty slot, or a card edge that is not making good contact, or something more serious I don't know.
Main boards for this model cost more than it is worth unfortunately.
There is a reset button on the main board, ...
One more question. When you have a memory LED on that slot 2, does the front panel power LED flash at all? It SHOULD either flash continually, or repeat a pattern of three flashes.
If that front panel light does NOT flash, other than the initial power on, then that may be another proof that either you have a bad riser - swap again to make sure that the problem doesn't simply stay with the same riser, or as the previous post, you likely have a bad socket for the riser board in the main logic board. I would find a lighted magnifying glass, and check both riser sockets for physical problems/bent pins, or just a tiny bit of junk in the wrong place. You'll have two to inspect, so it should be easy to compare.
 

littlecody8

macrumors member
Original poster
May 3, 2012
35
0
Clarification

  • Riser A Slot 2 does not work. LED at end is lit (on. not blinking.)
  • When using Riser A Slot 1 and 2 only slot 1 is recongized.
  • When using Riser A Slot 1 and 3 both slots are recongized.
  • When using Riser A and Riser B only Riser B is recongized. Riser A is disabled. (I'm assuming because of the Slot 2 failure.)
  • I've tested all ram. Two methods: 1. Four in riser B and 2. One at a time in Riser A Slot 1. All came up as clean.
  • Both Risers in socket A do the same thing.
  • Both Risers in socket B work fine.

Is this easier to understand?

All this lead me to the conclusion that there's a problem with the socket. Not the riser board.

So for now I'll just be using the four slots in Riser B.

The price I paid for it is pretty much the going price for parts/as is units so I'm not certained about it. Was just hoping it was human error instead of an internal problem.