Double your RAM:

Using, learning, programming and modding the Gigatron and anything related.
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Posts: 501
Joined: 14 May 2018, 08:29

Re: Double your RAM:

Post by at67 »

Nice pics, discreet job like cde's, welcome to the club.
Posts: 37
Joined: 11 Jul 2021, 22:12

Re: Double your RAM:

Post by giobbi »

hi all,

I finally made the 64k upgrade. I decided for a different solution, I put a socket that can be used for both 32k and 64k chips.

Since I hadn't a 32 pin socket (and frankly I'm too lazy to remove a 28 pin socket if I can avoid it :lol:) I decided for a Frankenstein socket: I cut a portion of the socket (pins 1,2,3 and 26,27,28) and I removed it. Then I built the replacement in a MacGyver way:
IMG_20210819_090710.jpg (309.48 KiB) Viewed 2800 times
I lowered the 4 (2+2) extra pins with the Dremel, so they don't touch the board (I checked it out later passing a piece of paper between the pins and the board: the papel have to pass freely behind the pins to be sure they're far enough from the board to prevent any unwanted contact).
IMG_20210819_090700.jpg (99.23 KiB) Viewed 2800 times
The red wire (A15 line) comes from an old, burnt pinball coil; it's very well insulated (it's hard to remove the red coating) and thin enough to pass between two socket pins
IMG_20210827_120524.jpg (384.54 KiB) Viewed 2800 times
And here we have the 64k RAM chip installed:
IMG_20210827_120623.jpg (185.63 KiB) Viewed 2800 times
And of course the Gigatron liked it :-)
IMG_20210827_120739.jpg (708 KiB) Viewed 2800 times
IMG_20210827_120456.jpg (641.89 KiB) Viewed 2800 times
Posts: 76
Joined: 30 Sep 2020, 22:19

Re: Double your RAM:

Post by Sugarplum »

That's a neat way to do that.
Posts: 86
Joined: 07 Jun 2021, 07:07

Re: Double your RAM:

Post by veekoo »

Time to do 64K RAM upgrade mod. I did it from the top of chip.

Now that I have 64K RAM, what are the top applications benefitting from more memory?

btw. I've tested most of the programs marked _64k_
IMG_1047.jpg (4.49 MiB) Viewed 1019 times
Posts: 2
Joined: 02 Sep 2021, 22:33

Re: Double your RAM:

Post by psergiu »

Upgrade worked fine with a generic 128k x 8 TTL SRAM: MT62C1024P-70L
Could not find a 32-pin socket in parts bin so I soldered AWG30 wires under the RAM chips
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Posts: 1
Joined: 03 Jul 2022, 04:17

Re: Double your RAM:

Post by llevet »

You can also replace the HM628128LP-7 (128Kx8) by a TC551001CP-70L or better speed TC551001CP-55L
The advantage for TC551001CP over HM628128LP is it only have half of the power consumption and it exist also in 55ns.
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