Questions regarding a 4mb update on 1040STF, motherboard C070523-001 REV. C

[Globox]

Hi there!
I'm a total noob at electronics, so forgive me if these are stupid questions...
I'm really just following steps without really knowing what connections I'm making

Since I've got a different motherboard than the guides I could find (mine is C070523-001 REV. C), I thought I'd be sure and post some pictures to see if I need to do anything different.
So what I'm not sure about is how many resistors I have to lift to disable the RAM on my board, and where to connect them to.
(I suppose it's all the way on the left side of the board on my revision, looks like the same part)
I'm also not sure which way the shifter pcb should be fitted into the socket on my motherboard, and which way the original chip is fitted into the socket on the shifter pcb.
Could anyone give me a little help?

Thanks a lot!

[exxos]

Its the 4x 68R resistors (R90,93,94,91) , lift the right side and connect to 5V somewhere.

EDIT:

In fact https://www.exxosforum.co.uk/forum/viewt ... =20#p48498

[Globox]

Alright!
Do I also have to remove the purple parts between the ram chips?
Also still not sure which way the shifter fits on the board...
I was thinking all text on the chips and board should be in the same direction, but then i saw that the MMU chip is fitted with text upside down so that's not it I suppose :p

[Steve]

Alright!
Do I also have to remove the purple parts between the ram chips?
Also still not sure which way the shifter fits on the board...
I was thinking all text on the chips and board should be in the same direction, but then i saw that the MMU chip is fitted with text upside down so that's not it I suppose :p

You don't need to remove the little blue caps. And with the shifter socket, look closely on the socket and the PCB silkscreen it has a half circle cut out indicating the same cut out on the chip.

[exxos]

There is a image on my website... https://www.exxosforum.co.uk/atari/last/4MBMMU/index.htm


Once tested, remove the old DRAM chips, done.

C070523.jpg (157.4 KiB) Viewed 5517 times

[JezC]

Also still not sure which way the shifter fits on the board...

On my C070523-001 Rev C (and also on two Rev D) boards, the shifter has pin 1 (near the circular depression on top of the chip) in the top right, so it's basically the same orientation as the 68000.

I have a 4meg upgrade in my Rev C board (it's been there for about 30 years now)...

Good luck!

[exxos]

Maybe someone can take some more images for my site

[JezC]

Will try to get some pictures later this evening...

[Globox]

Ok so i turned on my atari, and something must have gone wrong...
The Atari turns on, but my monitor gets no signal...
On the keyboard, the bottom left LED lights up, but the top right one doesn't. (when turning it on, it flashes very briefly and dim)
I tried to put everything back the way it was, so i soldered the resistors back into place, took the mods out, and put the shifter chip back into place, but that doesn't really fix it.
Now my monitor does get a signal, but it says the signal is not supported.
Does anybody know what could have gone wrong?
(I followed this video
Thanks!

EDIT:
Have tried the keyboard on another Atari and that works just fine, with both leds turning on, so that still works

[exxos]

Monitor not working may be bad cable / socket, bad connection on GLUE..

EDIT:

GLUE generates video frame even on a dead machine unless the 8Mhz clock is missing or bad connections on GLUE etc.