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Grand Ram Card Schematic


Shift838

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  • 4 years later...

Some interesting things I’ve found with my Grand RAM….

 

1) U13, 74LS05 has a purposely bent out pin (10?)


2) Jumper wire between the 9901 pin 2 to U22, pin 10

 

3) Jumper wire between U9, 74Ls242N pin 12 and Q3

 

4) Jumper between what’s supposed to be D4 and R11, along with a cut trace between Q3 and R11.

 

5) A resistor across U17, pins 26 and 28.  

 

 

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89960157-0EF7-4F0F-9277-82C85A1FD8A9.jpeg

88479414-F72D-423B-A023-CC783562BAC1.jpeg

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  • 1 year later...
On 11/30/2022 at 5:54 AM, dhe said:

This should help, looks like that battery has three legs.

DSADA00289.pdf 8.3 MB · 9 downloads

I haven't replaced mine yet, and thankfully there wasn't much battery leakage at all, but I eventually do want to replace it.  However, I don't want a potential leak candidate again, so I've been looking at supercaps.  I just need to figure out how much amperage draw these things have and get some help doing the math to see how long it lasts when the PEB is off.

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