Anyone know how to determine RAM/SSD configuration on dead 820-01958?

[ugamazing]

I'm hoping to find a way to easily (and reliably) determine the RAM/SSD configuration of a dead board--in this case, an 820-01958.

I've checked all over the board for any configuration codes to compare to the schematic BOM info pages, but no luck. Chip markings not useful; I can pull some ROM dumps if anyone know which one may include configuration info. Maybe the T2 ROM? May try to compare RAM configuration resistors as on older 00165 boards, but hoping there's an easier way before doing that.

Curious if anyone may know this. Would be very helpful for us; thank you in advance!

[ugamazing]

Re: Anyone know how to determine RAM/SSD configuration on dead 820-01958?

OK, I think I got the RAM figured out via RAMCFG info:

I believe that if a board has R1490 or R1492 populated, it's 16GB. If a board has NOSTUFF for R1490 and R1492, it's 8GB.

Someone can correct me if I'm wrong.

[mon2]

Re: Anyone know how to determine RAM/SSD configuration on dead 820-01958?

Hi

Search for 'strap' keyword -> look at the DRAM strap table.

8GB = 8 GB of RAM onboard.
16GB = 16 GB of RAM onboard.

That is last conclusion we came up with and hope to 'soon' perform upgrades with our BGA rework table. Ironically, we received a board back that we shipped overseas for a 16GB upgrade (iMAC A1418) so very very likely it is the upgraded ram that is the fault.

The iMAC LED pattern is:

1 - solid on = AC ok.
2-3 blink and then repeats so failing the RAM test.

Was out in the field for ~6 months.

We will reflow the BGA DRAM devices.

[ugamazing]

Re: Anyone know how to determine RAM/SSD configuration on dead 820-01958?

Thanks, mon!

Yes, now trying to identify the SSD capacity externally. Primary reason is for replacing dead customer boards for retail/insurance purposes. We can certainly "ask the customer", but that would leave room for...dishonesty, lol. I have a feeling every customer will say they had 512GB+ of course, haha!