[32K RAM EXPANSION]

19 minutes ago, jedimatt42 said:

Sorry, I didn't mean to call it 'misinformation', I meant to say 'misleading information'. This was a 'whole thing' when I first released it. 

 

Other fun things are that the LED control input floats when the 4A isn't on. So with external power, you can influence it with your fingers... 

 

 

I appreciate you designing and releasing it for us to build and use. It is an awesome upgrade to make these old computers more useful and should encourage more development.

[32K RAM EXPANSION]

29 minutes ago, jedimatt42 said:

 

 

Some poor soul in the future is going to read that it 'works' and then lose a days XB programming because they followed this misinformation. 

 

This is extremely dependent on out of spec behavior of the chips and a bunch of luck. 

 

I'm glad that you have chosen to power it.

 

I’m just reporting the behavior as it concerned me that connecting the external power could damage something since the memory expansion functions when the 32K is set to external. I have built 3 of these and they all function this way. The TIPI, I’m sure would not work, but I didn’t try that. If this post could be seen as “misinformation”, then I would be happy to delete it. (If that is possible)

[32K RAM EXPANSION]

I am able to run games that require the extra memory when it is set to Ext and no power attached. I went ahead and setup the TIPI using the external power and all works well. Thanks for your help! (And for your work on these enhancements!)

[32K RAM EXPANSION]

I built a REV4 version of this expansion. It has a jumper, TI/Ext, to set for internal or external power. The board works great, but doesn’t seem to care how this jumper is set or if it even has a jumper. I want to install a TIPI and I need to use external power to do so. Question: is it normal for it to work with the jumper set in any position? Looks like setting to Ext connects 5V to pin one of the header the TIPI will connect to, so the external supply is definitely needed.

Thanks

[CHELCO 1983 600XL REV 3]

1 hour ago, kheller2 said:

 this being a CHELCO, the thing probably had dozens of screws and nuts holding the shield together.

Actually, it had 3 screws and some H shaped clips that you twist to hold the top to the bottom . You have to remove the board to disassemble it. I will probe it out to see what is connected under the port. 

[CHELCO 1983 600XL REV 3]

2 hours ago, kheller2 said:

I’m curious about the RAM wiring if it’s easier to go 64K.   Take the cart port off and see where they go. 
 

 

 

 

The cart port is melted in place, so would have to be damaged to be removed. I did upgrade it to 64K with the SRAM upgrade that installs under the CPU with one solder point that is easily reversed. I am debating a video upgrade. I will leave this as an easily reversed upgrade if someone in the future wants to go back to stock.

[CHELCO 1983 600XL REV 3]

2 hours ago, kheller2 said:

That put is at late July 1983 which is a darn early 600XL.  And it is NTSC correct?

That is correct, it is NTSC and works with my US TV.

[CHELCO 1983 600XL REV 3]

Other things to note

- the keyboard uses the 800XL style ribbon and connector

- the bodge wires on the switch (perhaps to use the rocker vs slider?)

- no traces or through holes for a monitor jack where the channel select switch is (no easy UAV install on this one!)

- why the bodge wires going under the cartridge port? Other pictures I’ve seen of this model don’t include those.

- the 28 pin socket for the BASIC ROM. The ROM itself is 24pin… Reminds me of some 1200XLs.

[CHELCO 1983 600XL REV 3]

7 hours ago, kheller2 said:

   Do you have a pic of the bottom sticker?

Here it is

[CHELCO 1983 600XL REV 3]

Looks like the long red wire going to the PBI is to bring 5V to 47/48. I guess this model was not designed for the RAM expansion, so they added it. Also, the holes make more sense when placed on the bottom case. Still, they seem an afterthought.

[CHELCO 1983 600XL REV 3]

Looks like the long red wire going to the PBI is to bring 5V to 47/48. I guess this model was not designed for the RAM expansion, so they added it.

[CHELCO 1983 600XL REV 3]

I have a rather unusual 600XL with a CHELCO 1983 600XL REV 3 motherboard. It also seems to have some mods to the board and the RF shield. See the pictures. Does anyone have an idea why these were done? The holes in the lower shield make no sense.

 

 

[Atari 1200XL Rambo issue]

10 hours ago, kheller2 said:

Check all three jumpers on the rambo, but I also think the ribbon cable to PIA is backwards.  PB6 is pin 16 (far right, black wire) but that wire runs to PB2 on the Rambo (According to the silkscreen).  Hard to see w/o my glasses anymore.

 

@kheller2 There’s nothing wrong with your eyes. The cable was indeed backwards with PB2 going to 16. I wonder if the person that installed it did that to try to fix the issue caused by A and D being backwards…. The video upgrade is far more complex than this and the picture is superb. I ran XRAM .22 and it reported the banks as expected. I’ll try MEM /X later. Thanks to you and @Nezgar for your expert advice.

[Atari 1200XL Rambo issue]

2 minutes ago, Nezgar said:

Nice deduction there @kheller2 and @JGRAHAM2! (Maybe I should become Nezgar2? )

 

I still think something is up there... we should see one more column in column 3, and row $8x should not show. Maybe check that wiring again.

 

Because SI2 thinks $8x has a full 4 banks, it probably thinks you have 256K of extended RAM. Some memory testers mistake that row as extended RAM, when it's really a mirror of the base 64K.

 

Checking a real 1980's RAMBO'd 800XL I have, SDX 4.49c detects 12 banks, not 8, and XRAM 0.22 should look like this:

 

Thanks, I’ll look into it further and report back. It will probably be tomorrow before I can.

[Atari 1200XL Rambo issue]

SI2 

[Atari 1200XL Rambo issue]

Looks like that did it, although MEM /X still reports it the same way.

[Atari 1200XL Rambo issue]

40 minutes ago, kheller2 said:

I could be reading this wrong, but it looks like you have B and D reversed on the Rambo.

 

Page 11 of the RAMBO guide.

Close, but it looks like A and D are reversed. Good eye. In my defense, I didn’t install this, just the 32in1, but whoever did, in general, did good work on the super video and the RAM upgrade. Double checking myself and fixing it now. I’ll report back. Thanks!

[Atari 1200XL Rambo issue]

1 hour ago, Nezgar said:

Try flipping the switch with the blue/yellow wires leading to it, and run the test again.

That switch is part of the super video upgrade.

[Atari 1200XL Rambo issue]

Here is the MEM /X result and my motherboard. Looks like MEM agrees with .21, but .22 sees 64K….

[Atari 1200XL Rambo issue]

I am using .21, so I will check with .22 later today. (And with the others you suggested) 

Thanks!

[Atari 1200XL Rambo issue]

I have a 1200XL with an Atarimax 32in1 OS upgrade, super video upgrade and a Rambo 256K memory upgrade. The problem is that it only reports 112K in XRAM.COM. I have tried various OS versions. There are no other issues. Anyone have an idea what the issue could be?
 

[Indus GT repair WD2797PL-02]

The new chip worked with no issues. I was able to read a disk. I’ll test it out fully once I get the drive back together.

[Indus GT repair WD2797PL-02]

14 hours ago, bob1200xl said:

How do you know it is bad and how do you know a new chip will fix it? I have some 2797s but I don't know if they are good.

 

Bob

 

I switched it out with one from another Indus drive and it resolved the issue. I was getting an H3 error code.

 

Edit: I have a 2797 coming, so I’ll update this thread when I get it. It is a WD2797A PL

[Indus GT repair WD2797PL-02]

I have a drive with a bad WD2797PL-02 chip. I’ve tried to source a new chip, but the prices I’ve seen are very high, except for some shady looking sites. Any ideas of a source or alternative for this chip?
 

[Rotary switch for 4 in 1 OS]

14 minutes ago, Nezgar said:

Do you have an online link to that switch and handle, or part numbers? That would help to narrow down options on DigiKey or Ebay

 

The handle colour looks like it might match an XE well.

 

Here is where I got it
https://www.ebay.com/itm/114286114419?chn=ps&mkevt=1&mkcid=28

I printed the knob, so I would probably use gray for an XE.