Need Diagram for 130XE with 16-chip RAM

[Xebec]

Hey folks - I've been scouring the internet to try to find a diagram about how the XRAM Bank on the 130XE is supposed to be wired up. I cut 2 or 3 traces by accident desoldering the failed MT RAM on that bank, and I'd like to wire/repair without total guessing.

 

Does anyone have a good diagram of how the Bank is supposed to be connected/operate?

 

Since it's my only working XE for now I just want to restore it to 128KB operation.. maybe do the 320KB upgrade later.

 

Thanks!

John H

 

 

[+DrVenkman]

Hey folks - I've been scouring the internet to try to find a diagram about how the XRAM Bank on the 130XE is supposed to be wired up. I cut 2 or 3 traces by accident desoldering the failed MT RAM on that bank, and I'd like to wire/repair without total guessing.

 

Does anyone have a good diagram of how the Bank is supposed to be connected/operate?

 

Since it's my only working XE for now I just want to restore it to 128KB operation.. maybe do the 320KB upgrade later.

 

Thanks!

John H

 

 

 

You should be able to simply see the traces you cut on the board visually and jumper them from a point just before the cut to the pin on the socket that the cut trace leads to.

[Xebec]

 

You should be able to simply see the traces you cut on the board visually and jumper them from a point just before the cut to the pin on the socket that the cut trace leads to.

 

Yes I can see them, but I'd still like to have a diagram or schematic for verification afterwards

 

Thanks!

[+DrVenkman]

 

Yes I can see them, but I'd still like to have a diagram or schematic for verification afterwards

 

Thanks!

 

You're over thinking this. The proof is in the pudding - Check your continuity, then power it up and see if all 128K show up. If DOS 2.5 gives the "Setting up 130XE Ramdisk" you know things are probably good.

[1050]

http://ftp.pigwa.net/stuff/collections/Atari%20documents/Technical%20Documents/130XE-Reference-Manual.pdf

 

http://atarionline.pl/v01/index.php?ct=utils&sub=A.%20Schematy

 

http://www.atarimania.com/documents-atari-400-800-xl-xe-technical-documents_3_8.html

 

At last link obtain Sam's Photofact schematic.

 

Note to self, 1050 service manual at last link has

cat's eye waveforms, don't recall ANY other document

that does either.

[+kheller2]

Note about the 1050... there are at least three online PDF's and none of them are 100% complete from what I can tell. Some are missing entire sections. There seems to be two official versions that were released. I will have to dig up my copies and create a unified one.

[Kyle22]

Here is SAM's for the 130XE.

 

130XE - Sams ComputerFacts.pdf

 

I believe the left bank is the first 64K, and the right bank is chopped into 16K slices to fit in the expanded RAM bank window. There are 2 resistors you can cris-cross to swap the bank assignments. Don't know off hand, but the attached file should help you find which ones.

 

 

 

 

[xrbrevin]

Hi All,

 

The first time i desoldered XE MT RAM, i did the same. i learned the hard way but i have a much better feel for it now - every day is a learning day :S

 

To rectify it, i found that most of the pins are shared across all RAM ICs in a discernable pattern - use a continuity test to isolate the bad track(s). i tested from the top IC to the bottom IC (testing through all 8 ) and if they didnt connect then i moved the test probes closer, 1x IC at a time and you soon narrow it down to the point of concern. Use a small piece of wire to bridge it to the neighbouring IC - PC IDE and floppy ribbon cables make great donor wire here retest continuity and when no bad tracks are found, power it up to test

 

it doesnt look great but its invisible when assembled. mainly, it will save it from being condemned to "parts donor spec"

 

i think Jerzy Sobola's schematics are nice and clear:

https://archive.org/details/Atari130XE_Schematics

 

Hope you find this helpful

 

 

I tried the 320k upgrade but i was unsuccessful. i found out later that you need to also use the newer OS ROM (I think!) - the one that includes the 4x extended memory banks in the Atari self test.

I would advise you scan the forums for reference to this as it was a bit disappointing after all the hard work!!

 

 

Regarding the mention above re: 1050 cat-eye waveforms, the Indus GT service manual gives some worthwhile info here and it uses a Tandon mech like the 1050 so it may be worth a check out:

https://computerarchive.org/files/comp/manuals/atari/INDUS_GT_Field_Service_Manual_(Atari).pdf

 

have a good one

Nick

Edited July 29, 2017 by xrbrevin