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Asure

Strange 600XL ram expansion

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Hi all,

 

I recently got nostalgia in my veins, and went to dig up my 600xl from the attic. I haven't powered it on, as the tape recorder (a 1010) is broken, some of the buttons are snapped..

Probably end up getting some SD card load thing later on.

 

I remembered that my mother had this upgraded by a co-worker (she did accounting at an electronics company). I also recall it sometimes had a wierd problem, cold-booting was the only way to get certain games going. For example, if the 600xl had been off the whole night, i could load pitfall II from tape with no problems, and play all day. If i powered it on/off, it would refuse to load anything from tape, throw random boot errors, and so on. Ram rom always tested out ok if i remember correctly. The computer was pretty much useless unless i stuck to the same game the whole day :)

 

I popped off the lid, as i now know a bit about electronics myself. I found two 41464c rams inside instead of the 4464. Could this be the cause?

I took a few pics of the ram mod, maybe an expert can see if there is something wrong?

 

http://dl.dropbox.com/u/6773475/Atari600xl/20110916_200119.jpg

 

Could the use of these 41464c rams explain my 'cold boot after a night with no power' experiences?

Would replacing them with 4464's sort me out?

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Hello,

 

The answer is yes and no at the same time.

Yes, the Ram-chips are causing the problem and no, there's nothing wrong with them.

It cannot be solved with other chips of the same type.

The problem is caused by the better quality of the chips, the internal capacity of the memory cells is bigger.

This is because the refresh time must be longer. 4 times as much cells to refresh, at the same access time.

So if you switch back on a little too soon, the computer will do some kind of warm boot.

But there's a workaround and a way to notice beforehand.

When you power up the computer, there's a noise. This is the serial bus checking for devices.

This noise is different or missing if you switch back on too fast.

The cure is to take a game cartridge and stick it in. Now have the game start.

Switch off, remove the cartridge and boot again. Now it should be (sound) ok.

Another way could be to go to the selftest (BYE from Basic ) and let the ramtest work for a little while.

Then switch off and back on. Notice the sound. :cool:

 

BR>

Guus

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Hi all,

 

I recently got nostalgia in my veins, and went to dig up my 600xl from the attic. I haven't powered it on, as the tape recorder (a 1010) is broken, some of the buttons are snapped..

Probably end up getting some SD card load thing later on.

 

I remembered that my mother had this upgraded by a co-worker (she did accounting at an electronics company). I also recall it sometimes had a wierd problem, cold-booting was the only way to get certain games going. For example, if the 600xl had been off the whole night, i could load pitfall II from tape with no problems, and play all day. If i powered it on/off, it would refuse to load anything from tape, throw random boot errors, and so on. Ram rom always tested out ok if i remember correctly. The computer was pretty much useless unless i stuck to the same game the whole day :)

 

I popped off the lid, as i now know a bit about electronics myself. I found two 41464c rams inside instead of the 4464. Could this be the cause?

I took a few pics of the ram mod, maybe an expert can see if there is something wrong?

 

http://dl.dropbox.com/u/6773475/Atari600xl/20110916_200119.jpg

 

I'm no expert, but your mod is different from the one I've seen. The pins on the chips are not bent up and yours is going to different places. Maybe an expert can tell me if the differences are significant. The 41464c is the same as my chips.

(I got in the middle of your post.)

 

Could the use of these 41464c rams explain my 'cold boot after a night with no power' experiences?

Would replacing them with 4464's sort me out?

post-21816-0-37254100-1316214013_thumb.jpg

Edited by russg

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I googled a bit, and came across the following threads/guides..

 

An AtariMax original doc, and a thread on ram chips. These seem to differ from my mod a bit, but nowhere is the 'cold boot' effect described..

 

Differences:

 

Guide has U18 #9 going somewhere else. Mine goes to U18 # 7

The third wire connects between pin 9 of the 74S32 at location U18, and

pin 45 on the parallel bus.

 

Guide has U5 #3 different. Mine goes to U15 #9

The first wire should

be connected between pin 3 of the 74LS158 at location U5, and pin 20

of the parallel bus on the 600XL.

 

Guide has U6 # 9, mine goes to U15 #15

 

The second wire should be connected between

pin 10 of the 74LS158 at location U6, and pin 18 of the parallel bus.

 

The thread mentions this mod which involves U16, a resistor cut, and U9 solder pads.

 

I've yet to find a version that matches the hack done per my picture, but maybe the effect is the same? Can someone tell me, if the 'cold boot effect' exists on all modded 600xl's?

 

Edit: Russg, your pic seems to match the 'Don Neff' version. Does the resistor/wire touch the points in the tracec on the right? Or is it hovering above it? I cannot tell from the picture. Guide doesn't mention it.. :)

Edited by Asure

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the cold boot effect happens on any memory modded XL... its effects are more significant on yours cause of the chips your using, this is also an issue on 800XL's with 256k memory upgrades...

 

this has some info on it, and a way to get around it...

http://atrey.karlin.mff.cuni.cz/~pavel/atari/freezer.html

 

 

sloopy.

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I googled a bit, and came across the following threads/guides..

 

An AtariMax original doc, and a thread on ram chips. These seem to differ from my mod a bit, but nowhere is the 'cold boot' effect described..

 

Differences:

 

Guide has U18 #9 going somewhere else. Mine goes to U18 # 7

The third wire connects between pin 9 of the 74S32 at location U18, and

pin 45 on the parallel bus.

 

Guide has U5 #3 different. Mine goes to U15 #9

The first wire should

be connected between pin 3 of the 74LS158 at location U5, and pin 20

of the parallel bus on the 600XL.

 

Guide has U6 # 9, mine goes to U15 #15

 

The second wire should be connected between

pin 10 of the 74LS158 at location U6, and pin 18 of the parallel bus.

 

The thread mentions this mod which involves U16, a resistor cut, and U9 solder pads.

 

I've yet to find a version that matches the hack done per my picture, but maybe the effect is the same? Can someone tell me, if the 'cold boot effect' exists on all modded 600xl's?

 

Edit: Russg, your pic seems to match the 'Don Neff' version. Does the resistor/wire touch the points in the tracec on the right? Or is it hovering above it? I cannot tell from the picture. Guide doesn't mention it.. :)

No, the resistor is cut from the motherboard and the wire soldered to the 'dangling' cut side.

 

Here's the instructions I followed, (I think).

 

Msg #8999 Sunday, August 14, 1994 17:39 GMT

From: [email protected]

Subject: Re: Atari 600XL memory upgrade info

 

At the request of several users who have asked for info regarding the

upgrading of the 600XL to 64K, the following text has been pulled from

the February,1988 issue of Michigan Atari Magazine by Don Neff.

 

This memory upgrade requires 3 short lengths of wire and two memory

chips (HM50464P or equivalent 4464) to provide a full 64K.

 

In addition, the diagrams have been converted to ASCII characters to

give you a better idea of what you will be looking at.

 

Performing this (or any) modification is done at your own risk.

 

_____________________________________________

 

MAKING THE MODIFICATION:

 

Open the case of your 600XL and remove the circuit board. The 4416

(4 bit x16K) memory chips, U11 and U12, are located at the front right

More? Y/n

 

 

corner of the cartridge holder. Gently remove both of these chips and

replace them with HM50464P (4 bit x 64K) memory chips (or 4464 equivalent).

 

Remove U16 (a 74LS51 chip to the left of U11) and bend pin #8 up so it

sticks straight out from the chip body as shown in Figure 1. Insert U16

back into its socket. Unsolder and lift the lead of resistor R36 (as

indicated at point "Y") in Figure 1. Solder a jumper wire between this

resister lead and pin #8 of U16 (point "X"). Insulate the ends of the

jumper so that they will not touch other parts of the circuit.

of the circuit.

 

Locate U5 and U6 (74LS158) which are directly in front of U11 and U12.

These chips handle the row and column addressing inside the memory matrix.

We have to add two lines to these chips. Gently remove U5 and bend

pin #3 up so it sticks straight out from the chip body as shown in

Figure 2. Insert U5 back into its socket. Now remove U6 and bend

pin #10 out and replace it back in its socket. Notice that the two pins

you bend are nearly touching the other chip. Cut enough off of each of

the two pins to prevent any shorts.

 

Locate U14 which is to the left of U5 and U6. Notice the circuit traces

to the left of U14. We are interested in the two traces indicated in

More? Y/n

 

 

Figure 2 as points "C" and "J". Connect the jumper from the pad at

point "C" to point "D" (pin #3 of U5). This jumper sends address bit

A15 to U5. Connect jumper from the pad at point "J" to point "K"

(pin #10 of U6).

 

Make sure all your IC ships are inserted properly with their #1 pins in

the lower left corner. Check your jumper wiring agains Figures 1 and 2.

You should have a jumper from point "X" to point "Y". You should have

a second jumper from point "C" to point "D", and a third jumper between

points "J" and "K". Make sure the jumper ends are insulated to prevent

shorts with nearby objects. Reassemble your computer case and run the

memory self test as a final check.

 

If all has gone well, you should now have the same memory capacity as

a stock 800XL.

 

(The ASCII pictures are re-formatted and don't make any sense, so I deleted them.)

Edited by russg

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Hi all,

 

I recently got nostalgia in my veins, and went to dig up my 600xl from the attic. I haven't powered it on, as the tape recorder (a 1010) is broken, some of the buttons are snapped..

Probably end up getting some SD card load thing later on.

 

I remembered that my mother had this upgraded by a co-worker (she did accounting at an electronics company). I also recall it sometimes had a wierd problem, cold-booting was the only way to get certain games going. For example, if the 600xl had been off the whole night, i could load pitfall II from tape with no problems, and play all day. If i powered it on/off, it would refuse to load anything from tape, throw random boot errors, and so on. Ram rom always tested out ok if i remember correctly. The computer was pretty much useless unless i stuck to the same game the whole day :)

 

I popped off the lid, as i now know a bit about electronics myself. I found two 41464c rams inside instead of the 4464. Could this be the cause?

I took a few pics of the ram mod, maybe an expert can see if there is something wrong?

 

http://dl.dropbox.com/u/6773475/Atari600xl/20110916_200119.jpg

 

 

One other thing. You need to leave the machine off for about 15 seconds before turning it back on. Sometimes the memory needs to 'unload' before you do a

power off/on.

 

Could the use of these 41464c rams explain my 'cold boot after a night with no power' experiences?

Would replacing them with 4464's sort me out?

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pics for the above text...

 

(just wrap them in a 'code' segment, makes things monospaced ;')

 


                                 U12--------------   R36    R38
                            ---->   )    4416    |   |       |
            Replace with   |        --------------  |^|     |^|
            HM50464p  (4464)                        |_|     |_|
                           |     U11--------------   |       |
                           ----->   )    4416    |   0(Y)    0
                 (X)                --------------   | \  
                  /----------------------------------|  Unsolder and
 U16 |_|_|_|_|_|_|_  Lift pin here                      lift here
    |            8 |             
     )   74LS51    | 
    |o_____________|
     | | | | | | |

                       (FIGURE 1)




                                         U5 |_|_|_|_|_|_|_|        
              U14                          |               |
               |_|_|_|_|_|_|_|              )   74LS158    |
Board  || |    |               |            |o___3__________|   Lift
Traces || |     )   74LS158    |             | | | | | | | |    pins as
      || |    |o______________|      ___________D        _____ indicated.
     / | |     | | | | | | | |      |                   K     |
     | C |                          |    U6 |_|_|_|_|_|_|_|   |    
   0 0 0 0   __Connect to pad C_____|      |            10 |  |
   | | | J                                  )   74LS158    |  |
  / / / /    __Connect to pad J____        |o______________|  |
 / / / /                           |        | | | | | | | |   |
__|_|_|_|_                          |                          |
         |                         |__________________________|
  U9     |
__________|

                       (FIGURE 2)


 

sloopy.

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i just looked over your pic and a schematic, and the U5/U6 to U15 wires are the same as D->C and K->J, and the other jumper just accomplishes the same as the wire from the resistor to U16 in another method...

 

 

so your mem upgrade is fine...

 

 

sloopy.

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I fired her up for the first time since 199? today, and she runs fine. Except, my POS Samsung LCD tv has a jumpy picture (even over RF).. but the Atari still works.

 

I can confirm i hear the 'brrrr.rr.rr.rr' pattern after i leave power off for at least 15 seconds or do the cartridge trick so i guess everything is fine.

Unreliable 1010 combined with the 'cold boot' was probably the reason back in the 80's-90's i could hardly play with it. Eventually the 1010 ended up with broken play/rewind buttons (any replacements?), and i got a C64 at some point..

 

So now 1010 is broke, so i guess getting a sio2sd would sort out my nostalgia fix for a while. A little OT, but what's the cheapest way to get a (prebuilt) one (No case needed,i'm in the Netherlands, sellers can pm me.)?

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I've yet to find a version that matches the hack done per my picture, but maybe the effect is the same? Can someone tell me, if the 'cold boot effect' exists on all modded 600xl's?

 

Both of my Rambo 800XL's can do this sometimes. My cure is to wait 30 secs or so before powering back ON.

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My machine does the same thing. Takes about 10-15 seconds before I can properly cold boot. I just recently upgraded my machine using the same method.

 

I stumbled upon this which might be a better solution than wearing out my power switch and stressing internal components:

 

http://www.b-pahl.de/atari8bit/Computer/computer.print.html#coldr

 

I have a few 74LS123's. Might try it this weekend.

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