Atari 130XE 4164 best replacement or upgrade RAM chips?

[E474]

Hi,

 

I recently got a couple of "dead" 130XE's thrown in as part of a deal.

 

The first 130XE only powers the RED keyboard LED, and doesn't output a TV signal (can't be found with the TV's auto-tune). It's also playing dead when I try it with a SysCheck board, so I am putting it aside for the moment.

 

The second 130XE can be tuned in, but gives no picture. When I try it with a SysCheck board, I get U14 marked as bad. So, I need to get some more RAM chips. Is there any reason I should get anything other than 4164 dips? What I'm trying to ask is, are there any mods that involve replacing the 4164 chips with some other chips, giving more available memory? I'm guessing that this would be the ideal time to do such an upgrade, rather than ordering a load of 4164's that I don't need. I should point out both 130XE's have 16*4164 chips, so I would probably order 32 * 4164 to simplify shipping, etc.

 

My plan is to just replace the defective U14, but I don't know if the other bank of memory (the extra 64K of a 130XE) has defects (I don't think this is tested by the SysCheck board - though I think it should be!). I don't think I can test this until U14 has been replaced. Although I have seen a lot of advice saying it's best to replace all the RAM chips, I don't want to do this unless absolutely necessary, as they are all soldered on. On the other hand, if there is a mod that involves replacing them all with another set of RAM chips, this might be a good time to do so (if you see what I mean).

 

Finally, the second 130XE runs quite well with the SysCheck board plugged in (I'm really pleased with the SysCheck board, btw). I was playing Mercenary on it (48K and high res versions) from disk, and the keyboard is fine, apart from the 'H' and 'J' keys not working. I'm tempted to try swapping the keyboard from the set aside 130XE, but I don't want to do too much unplugging/plugging as I have heard that 130XE keyboards can be quite fragile.

 

Any advice on the best RAM chips, and keyboard swapping strategy would be appreciated.

 

Thanks!

 

 

[xrbrevin]

you can ensure the second bank of ram is tested by swapping the ends of 2x resistors over. i did it once but cannot remember which 2 so maybe another forum user can advise or google it?

the XE keyboards are not fragile per se, but they have a reputation for failure due to being manufactured to a price resulting in weak mylar... i have one that has failed on the bend of the ribbon cable so it is un-mendable but if you have dead traces on a flat, they can be repaired with automotive conductive silver paint (used for heated rear window repairs)

hope this helps!!

 

there is a mod to give 320kb ram - google it. you have to replace the second bank with 8x 41256 chips and add some other glue logic chip plus some wires. this may free up some spare chips for your other XE - unless they are MT brand, in which case they are a "time bomb" so effectively they are bin fodder

Edited July 24, 2018 by xrbrevin

[+Nezgar]

If it's just 2 keys not working,it may be repairable with a silver conductive pen ink to bridge a cracked or corroded trace on the mylar... but if you don't already have the supplies it's honestly easier / cheaper / save time to just get a new mylar from BEST. I probably spent 3x more $$ and time than if I hadn't tried to fix 2 130xe mylars myself and just got the new mylars in the 1st place.. Mine were too far gone... these were single sheet mylars, I'm not sure about availability of the 2 layer mylars (my 130xe's are all single)

[_The Doctor__]

At this stage it wouldn't hurt to swap keyboards and see, but I would disconnect both keyboards beying careful not to do much flexing if possible getting the ribbon out or in...

 

I would take ram from second banks to fix first banks on both, I would replace second banks with 256k chips and do the Peterson antic fixed upgrades or similar.

 

The end result would be standard mode but 128/192k and 320k mode for both... it will cost less and upgrade the machines to play more demos and games...

 

If after the swap the keyboard still don't work replace the mylars is a great thing and you need to know which kind you need to order... I'd order 1 extra sheet you'll need em for another keyboard soon enough.

[E474]

Hi,

 

Thanks for the pointers and advice.

 

From the looks of things, the quickest test is going to be swapping the resistors. Almost all the memory is MOSTEK, so I'm going to leave the first bank alone, apart from U14 (and possible U16, which doesn't look like a MOSTEK chip, though I am not sure). I'm attaching a picture to show the memory, and also which resistors need swapping, according to this thread - https://atariage.com/forums/topic/218035-atari-130xe-ram-test-failure/ (please correct me if I am wrong). Also am going by the attached PDF from the SAMS 130 XE ComputerFacts manual.

 

I think I will try swapping the keyboards, and see how that goes.

 

I have also tried to find out more about upgrading the memory. This thread looks like a good start - http://atariage.com/forums/topic/138299-ram-upgrade-options/ - but I am not sure about the different Antic/CPU addressing schemes, and also some of the external links are dead. Hopefully the second bank will all be OK, this would give me replacement chips for the first bank. If only some of the chips are OK, I'm sure that the SysCheck board will tell me how many are bad, but I don't know how easy it is to map bank 1's layout to bank 2's. Also, the Peterson upgrade talks about "B: Z2-------> CO25953 (Custom chip by Atari)" - but there is one present in the 130XE (it's the chip underneath the circled resistors), so does this only apply to upgrading a 65XE?

 

Thanks again for the help, any further help would be appreciated.

130_ram.pdf

Edited July 24, 2018 by E474

[xrbrevin]

yes, the 65xe and 800xe models do not come with a CO25953 - you have to add one as part of the 128k upgrade mod

[E474]

Ah, just found this link, which seems to be 130 XE specific: http://atari.a8maestro.com/info/8ball/memory/mem130xe1.txt

[_The Doctor__]

I highly suggest the peterson 320 with antic upgrade....

[Mathy]

Hello guys

 

yes, the 65xe and 800xe models do not come with a CO25953 - you have to add one as part of the 128k upgrade mod

 

Or one of the alternatives. Check this out.

 

Sincerely

 

Mathy

[_The Doctor__]

he has 130xe's and the picture shows freddy as being there... and the CO25953 as well

Edited July 25, 2018 by _The Doctor__

[E474]

OK, I'm quite happy to try the highly suggested "peterson 320 with antic upgrade" - does anyone have a link to the most up to date version (or similar)? Any help would be appreciated, am looking forward to having a fully working 130 XE!

[Mathy]

Hello Doc

 

he has 130xe's and the picture shows freddy as being there...

 

CO25953 is a small 16 pin chip, Freddy is one of the big (40 pin?) chips.

 

Sincerely

 

Mathy

[_The Doctor__]

 

I haven't read this to make sure it has the switch and antic mod included... that was added later but it's what I found on a quick search

The 65XE 130XE/320K Upgrade!

 

by Scott Peterson

 

I have written the following documentation in such a manner that you can

use it to help you keep track of your progress as you assemble this memory

enhancement. Simply place a check in the space provided as you proceed. This

will allow you to readily follow your progress, and pick back up where you

left off if you should have to stop.

 

Once you have finished this upgrade you will then have in your possession an

Atari 65XE with 320K of total ram. This is broken down into chunks of 64K of

standard ram, and 265K of page mapped ram. This upgrade is 100% compatible

with the previous 130XE/320K upgrade and therefore will run all programs that

the earlier enhancement ran.

 

Disclaimer:

 

The Author nor this BBS claim any responsibility for any type of damages

incurred by do this modification

 

The equipment you will need is:

 

A: A medium sized Phillips head screwdriver.

 

B: A very small jeweler's screwdriver with flat blade.

 

C: Soldering wick (recommend Chem-Wik .100 inch size), or vacuum desoldering

pump.

 

D: Soldering station (like Weller model WTCP), or LOW wattage soldering

pencil of the 15-25 watt variety.

 

E: Small pair of needle-nosed pliers.

 

F: #30 gauge wire (Jameco #130 BE)

 

G: Wire stripping tool for #30 gauge wire ("Clip and Strip" Jameco #CAS-130).

 

H: Heat shrink tubing or black electrical tape (tubing preferred).

 

I. Small pair of wire snippers.

 

J: Optional: Small carpet sample or blanket.

 

The parts you will need are:

 

A: Z1-------> 74LS158

 

B: Z2-------> CO25953 (Custom chip by Atari)

 

C: Z3-Z10---> 256K Ram chips #41256-150 (8 required)

 

D: R1,R2----> 33 ohm 1/4 watt resistors (2 required)

 

And here we go.................

 

1.___Place carpet sample or small blanket on a clean, uncluttered workspace

that is well lighted.

 

2.___Situate all tools and parts on one side of your workspace.

 

3.___OPTIONAL: Get a fresh cup of coffee!

 

4.___Place 65XE face down on carpet. Remove all screws holding cabinet

together. Turn unit over. Remove top of cabinet and lay it in a safe place.

 

5.___Gently pull upward with fingertips on mylar extending from keyboard and

remove it from its connector. Place this keyboard assembly with the top of

the cabinet. Place screws in a small container so they won't be misplaced.

 

6.___Take needle-nosed pliers and turn all twist tabs on metal shield so it

may be easily removed. Remove all screws from outer edges of PC Board and

then place screws in your container, and the top and bottom shields along

with the bottom of the cabinet should be placed with the rest of the 65xe

cabinet.

 

7.___Place all ICs in front of you and proceed with the following:

 

a.___Bend up pin number 15 on all 8 of the 41256 rams. Then snip off the thin

part of the leg so all you have left of pin 15 is the "stub" or fat portion.

Do this on all 8 rams.

 

b.___Bend up all pins with the exception of 8 and 16 on the 74LS158. Leave

the legs on 8 and 16 long, and snip the thin part off all other pins on this

chip.

 

c.___Bend up all pins with the exception of 8 and 16 on the CO25953. Leave

the legs on 8 and 16 long, and snip the thin part off all other pins on this

chip.

 

d.___Take both 33 ohm resistors and snip the leads so their is 1/4 of an inch

of lead left on either end of each of these resistors.

 

e.___Place these chips to one side, and position the 65XE motherboard in

front of you. Locate IC numbers U9 through U16. You will find them running

along the left side of the motherboard. Take a piece of tape or a small black

magic marker and place a small mark next to the IC that is labeled U12. You

see the wisdom of doing so later on in this documentation.

 

8.___Proceed to piggy-back ICs Z3 thru Z10 inclusive on top of ICs U8 thru

U15 inclusive. Please take your time and be sure that each chip is facing

the same direction as the integrated circuit below it. Do a good job

soldering so not only will this upgrade work well but also will be pleasing

to the eyes when you show it off to your admiring friends!

 

9.___Cut 7 small pieces of #30 gauge wire, and use these to connect all 8 of

the pin 15s of the piggy-backed rams.

 

10.___Gently turn the 65Xe motherboard over exposing the underside to your

trusty soldering iron. Cut 7 more small pieces of #30 gauge wire and then

proceed to jumper all the pin 1s of the rams. Cut another piece of #30 gauge

wire approximately one foot long and solder it to pin one also and then run

it through a convenient hole in the motherboard. Turn the motherboard back

up with parts side once again smiling up at you.

 

11.___Grasp the 74LS158 and proceed to piggy-back it on top of an IC on the

motherboard labeled U24 which you will find at the front right of your

computer. Make sure it is facing the same direction as the chip you are

placing it on top of and proceed to solder pin 1 of the 74LS158 to pin one

of U24. Next solder pin 16 of the 74LS158 to pin 16 of U24.

 

12.___Grasp the CO25953 IC and proceed to piggy-back this gem on top of U2.

U2 can be found approximately in the dead center of your 65XE motherboard.

Again, please make sure both chips are facing the same direction. Remember,

a slow, sure job is often-time the fastest job overall! Proceed the solder

pin 1 of the CO25953 to pin 1 of U2. Next, solder pin 16 of CO25953 to pin

16 of U2.

 

13.___Grasp one of those 33 ohm resistors you have previously trimmed and

solder one end to pin 15 of Z3. Z3 you ask? Why that is the chip which has

been piggy-backed on top of U12. U12---you know that one! that's the chip

we so wisely marked before we started!

 

14.___Cut a short piece of wire and attach it to the free end of the resistor

you just connected to Z3 pin 15. Run the other end of this wire to the

CO25953 pin 10.

 

15.___Grasp the other 33 ohm resistor and solder it to the 74LS158 pin 4

(this is one of the ones you have previously piggy-backed.) Now take the long

piece of wire you had previously connected to all of the pin 1s of the rams

and solder this to the free of your resistor.

 

16.___Now take the metal bottom and place the motherboard back into this

protective housing.

 

17.___At the front of your computer on the lefthand side you will find R108.

Desolder the end of this resistor closest to the front end of the computer.

Solder a short wire to the new free end of this resistor, put heat shrink on

the connection, and connect the wire to pin 11 of the CO25953.

 

18.___Our next chore is to locate U6 which can be found near the center of

the front end of the motherboard. Please be careful as the traces on this pc

board are very delicate and will not be able to tolerate much abuse. Gently

desolder pins 23 and 24 of U6. The best way to do this is take your solder

wick, place it against the leg to be desoldered,and heat it until you see the

solder beginning to flow into the wick. Turn the motherboard over and make

sure all the solder is off of the pin on this side also. Repeat this step

with pin 24 also. Then take a small, flat-bladed jeweler's screwdriver and

use it to push the pins back and forth a bit. This will free up the pins and

allow you to remove them easily and not tear the living daylights out of the

board! Turn the motherboard back with the parts side up, and use that same

jeweler's screwdriver to pry pins 23 and 24 of U6 out of the board. Leave

them extended in a horizontal direction, snip the thin part of the leg off,

thus leaving the fat parts of these 2 legs for you to connect to later.

 

19.___Cut a small piece of wire, and strip either end. Connect one side of

this wire to the land where pin 23 of U6 used to be. Fasten the other end of

this wire to CO25953 pin 1.

 

20.___Cut a small piece of wire, and strip either end. Connect one side of

this wire to the land where pin 24 of U6 used to be. Fasten the other end of

this wire to CO25953 pin 2.

 

21.___OPTIONAL!:Get your second cup of coffee.

 

22.___Cut a short piece of wire, strip both ends, and connect one side to the

74LS158 pin 1, and the other side to U17 pin 30.

 

23.___Cut a short piece of wire, strip both ends, and connect one side to the

74LS158 pin 2, and the other side to U23 pin 15.

 

24.___Cut another short piece of wire, strip both ends, and connect one side

of this wire to the 74LS158 pin 3, and the other end goes to U23 pin 16.

 

25.___Cut another short piece of wire, strip both ends, and connect one side

to the 74LS158 pin 15, and the other end to pin 8 of the same chip.(74LS158)

 

26.___Cut yet another short piece of wire, strip both ends, and connect end

of the wire to CO25953 pin 6, and the other end to U6 pin 35.

 

27.___Cut another short piece of wire, strip both ends once again, and

connect one side to CO25953 pin 7, and the other end to pin 8 of the same

chip. (CO25953)

 

28.___Cut another short piece of wire, strip both ends once again, and

connect one side to CO25953 pin 9, and the other to U17 pin 26.

 

29.___Connect one end of this wire to CO25953 pin 12, and the other side to

U6 pin 23.

 

30.___Cut a short piece of wire, strip both ends, and connect one side to

CO25953 pin 13, and the other end goes to U6 pin 24.

 

31.___Cut a short piece of wire, strip both ends, and connect one end to

CO25953 pin 14, and the other end goes to the same chip pin 16.(CO25953)

 

32.___Cut yet another short piece of wire, strip both ends, and connect one

end to CO25953 pin 15, and the other end goes to U6 pin 5.

 

33.___Cut another short piece of wire, connect one end to CO25953 pin 3, and

the other end goes to U23 pin 12.

 

34.___Cut another short piece of wire, strip both ends, connect one end to

CO25953 pin 4, and the other end goes to U23 pin 13.

 

35.___Cut one final piece of wire strip both ends, connect one side to

CO25953 pin 5, and the other end goes to U23 pin 14.

 

36.___Check all your wiring, and rearrange it to be pleasing to the eye as

well as functional.

 

37.___Get your SpartaDos 3.2 that has the RD.COM file on it, say a prayer and

load 'er up! If it boots you probably are ok! If not, don't panic, simply go

back through section step by step, you will find it is probably some little

error or oversight.

 

38.___While you have your computer open it would be a good idea to solder the

joystick jacks, the monitor, I/O and power supply ports also. It may save

you a bit of aggravation later on!

 

39.___Reassemble your upgraded computer by placing the top metal cover back

over the motherboard. Turn all twist tabs and then insert the appropriate

screws. Gently plug the keyboard back in, position it in its slots in the

cabinets, and then place the cabinet top on. Turn over and insert all screws.

While you have it out, why not use a bit of cleaner on it to make it sharp!

If you don't have SpartaDos, then Run, don't walk to your favorite computer

store and get it!

 

For you programming types, here are the control numbers for location 54017

(PORTB).

 

#####################################

 

Bank # Control # Hex #

 

#####################################

 

Bank 1 ------->131----->83

Bank 2 ------->135----->87

Bank 3 ------->139----->8B

Bank 4 ------->143----->8F

Bank 5 ------->163----->A3

Bank 6 ------->167----->A7

Bank 7 ------->171----->AB

Bank 8 ------->175----->AF

Bank 9 ------->195----->C3

Bank 10 ------->199----->C7

Bank 11 ------->203----->CB

Bank 12 ------->207----->CF

Bank 13 ------->227----->E3<--|

Bank 14 ------->231----->E7<--|130XE

Bank 15 ------->235----->EB<--|Banks

Bank 16 ------->239----->EF<--|

 

#####################################

 

It is recommended to use SpartaDos 3.2, but you can also use MYDOS 4.1

or higher, and also Topdos 1.5 and higher with the 320k series of upgrades.

 

Enjoy your 130K 65XE!

 

Scott Peterson

 

[_The Doctor__]

correct they are both there..

the connection is not good with the bad weather, so I save often and go back to finish my post.... bad interweb service... calls drop also...

[_The Doctor__]

that page you sited looks like the peterson upgrade for the most part any way...

I have posted about the 192/320K switch with Antic Access on this forum but can't seem to dig it up, I probably also posted either the upgrades or links... search suddenly seems hopelessly broken these days..

[xrbrevin]

is it necessary to have the latest XE OS ROM to allow the Petersen 320k mod to work?

[_The Doctor__]

no, why?

[Tezz]

I'm about to do the Peterson 320K upgrade to a couple of 65XE's that I have here. It's been 11 years since I did the last one and I've had the parts and 41256 RAM for the others in storage ever since so it's high time they were put to use. Jurgen's 512Kb SRAM is another great option which I've installed in a couple of my XL's now although I'll make use of the parts for the XE 320K mod this time.

[E474]

This looks like a good write up of 130XE -> 320K https://www.exxoshost.co.uk/forum/viewtopic.php?t=732

 

Am going to try the resistor switch hopefully later today or tomorrow. Also keyboard swap. Am also wondering about combining parts order with parts for the Sdrive Max (Arduino something and elegoo screen) from Alibaba with thier $4 free parts offer.

[xrbrevin]

no, why?

 

i performed the peterson mod some time ago and i couldnt get it to work.

soon after, i found the 320k ECI port device and got that instead but im sure i read somewhere that the issue was it needed the newer OS ROM... maybe i was mistaken

[_The Doctor__]

Nice write ups, now find my modification here on AA and you will be assured it will run everything... sometimes you have to drop to 128/192K for every last little thing to run/work properly.

Edited July 25, 2018 by _The Doctor__

[1050]

i performed the peterson mod some time ago and i couldnt get it to work.

soon after, i found the 320k ECI port device and got that instead but im sure i read somewhere that the issue was it needed the newer OS ROM... maybe i was mistaken

The only thing the last OS version brought to the table

was a broken self test that would show only the four

additional blocks of extended ram across the bottom of

the screen and only if it existed. It only 'tests' two

banks of the four XE banks present anyway which is the

broken part. It does the same two twice and makes it

look like four banks have been tested.

 

I have not heard any reason why the Peterson

would not work fine with any XE if somewhat broken

ANTIC access is acceptable.

[_The Doctor__]

and remember the antic mod of tying the pads together or the added toggle mod fixes the antic situation as well

[Mathy]

Hello Doc

 

Tying pins together or using a toggle switch does not give you separate CPU and ANTIC access.

 

Sincerely

 

Mathy

[_The Doctor__]

it works well enough...

 

the simple if crude fix..

tie pins 14 and 15 of the socket for the PIA, together, (you know, that socket that you hopefully installed when you did your upgrade?),

If not, simply run a short jumper from the pad on the motherboard that pin 15 used to occupy, to pin 14 on the same chip, (the PIA).

 

of course you can always post up a more perfect solution.. that would be cool too

Shouldn't there be a way to use the halt line to tell it to switch the line automatically... a single added chip perhaps.? Instead of this other stuff that follows

 

the slightly more effort method with two modes...

I will continue to dig for my simple switch that puts things back to normal in 192k and does some tie in on 320k

here is another switch method... in the mean time...

 

 

since I've used the the simpler switched solution from day one of the upgrade, I think it works well enough but I haven't found the correct post of it yet... so I offer what metal guy came up with instead... I never noticed any problems with his or mine...

Edited July 26, 2018 by _The Doctor__