Continuing from the other 1690XA motherboard thread, it seems more appropriate for me to post here.
I too think there must have been something stored in the EEPROM's for the user-upgradable action to happen on the 169x cards, however I am keen to have a poke around just incase it's something trivial like the resistor mods.
My 16902A unit arrived yesterday, and it came with one 16910A installed. It was a bit of a "see what turns up" from the seller, but to my surprise the 16910A is a 500MHz state with 16M memory. Most of the eBay 16910A's I've seen have been 250MHz and low-ish memory depth, so keen to compare this to other 16910A cards to see if we can work out the upgrade combinations.
I have attached some images below of the 16910A 500M State, 16M mem card resistor array combinations.
Are any other users able to do the same of their 16910/11A's + list what state + memory depth?
I think the 16910A's would be more useful than the 1675x's / 16950 due to the 40-pin probe support, vs the pricey 90-pin ones.
I have also attached some images of my 16950A board ID resistors. The state timing for the 16950A's are fixed at 600MHz, but my board here has a mem of 64M. This would be nice to replicate on other boards as is the highest upgradable option.
If you are able to do the same, again maybe we can work out what combination gives what?
However:
The board has a sticker over the PCB legend, saying 16950A. I peeled this back, and it turns out it is a 16974A, which has a listed stock memory depth of 4M.
So I am curious to also see the board ID resistor combinations for a stock 16974A.
Unfortunately my stock board ID seems to be different that MarkL's 16754A -> 16756A tested upgrade.
I won't be able to power up the chassis for another day or so as waiting on some parts. So what the boards present in software will have to wait a day or two.
All the best,
Dan