Can you tell me what kind of VRAM SIMM this is please?

1 reply [Last post]
Joined: May 9 2015
Posts: 62

Hi folks....

Reading the CC FAQ (on the Mystic upgrade), it says to install two 512k VRAM SIMMs. The FAQ suggested having two 512K 70ns VRAM SIMMS, and two 512K 80ns VRAM SIMM around. And one may need to experiment to see what would work.

I want to search ebay and buy some, but I don't think I have enough information.

My 575 logic board came with two VRAM SIMMS. But I do not know how to tell if they are 70ns or 80ns. And I do not know how to tell if they are 512K or not.

Both my VRAM SIMMS are the same.

Each VRAM SIMM has 4 chips on one side. A paper sticker on the back says "630-0045 G9417". Both VRAM SIMMS are Apple branded and dated 1991. Printed on the SIMM is:041 820-0605-A. I see a A50 printed on the other end. I believe that they are 68 pin SIMMs. C5 is printed on the other side.

Can someone tell me if they are 512K VRAM SIMMS or not, and perhaps what speed?

Thanks in advance.


Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
Joined: May 9 2015
Posts: 62
How to tell the speed of the 575 VRAM


While not addressed in the CC FAQ here, I have found out how to tell if the 512 VRAM for the 575 logic board is 70ns or 80ns.

I found this:

"If you get the 80/40MHz upgraded LC575 logic board, you need 70ns VRAM
or faster, otherwise you end up with a black screen. The speed of the
VRAM SIMM is printed on each chip, e.g. part numbers ending in "-10"
means 100ns and are too slow, "-8" or "-80" means 80ns and are fast
enough for the 66/33MHz version fo the LC575, but the 80/40MHz version
would need chips with part numbers ending in "-70" or "-60".

I think I might start a *Color Classic FAQ for Dummies* in my own computer as I do the Mystic upgrade. All of you old timers know this stuff already. But us new kids, like me, don't. And with at least 1/2 of the links broken, it is hard to figure stuff out.

Once I have finished, I will send it to the moderator and see if the moderator thinks it might be worth posting.

jack the new kid