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Posts posted by JGRAHAM2

  1. 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.

    • Like 1

  2. 2 minutes ago, Nezgar said:

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


    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.

  3. 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!


  4. 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?

  5. 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.




    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

  6. 1 hour ago, Nezgar said:

    Very nice/clean install. I can't see clearly from the top-down photos, but are there sockets under the OS/BASIC ROM's, or are the multi-ROM adapters soldered directly to the mobo? If so you must be very confident you'll never need/want to remove them again in the future. It would kind of go against the main theme of detachable wires going on. :D

    Thanks. Most 600XLs are fully socketed. All 4 of mine are.

    • Like 1

  7. 18 hours ago, SS said:

    It's unbelievable how much 600XLs have gone up in price in the last two years!  I got all four of mine previous to 2020 and none of them were more than $75.  The last one was an eBay BIN for $38 in 2019!  ( Admittedly, I did think that one *was* a bit of a steal. :) )  I don't quite know why 600XLs have skyrocketed so much but I'm thinking of doing a RAM upgrade to one of mine and cashing in on it.  

    I have 4 of them too. I bought them as untested and had intended on putting a RaspberryPI in one of them, but I’ve been able to fix them or there was nothing wrong with them, so I have 4 working 600XLs. I have upgraded 3 with UAV, one with 64kb RAM, one 576KB and one with U1MB. The last will likely be upgraded to 64KB SRAM and left as it is otherwise. That upgrade is solder-less and easily reversible.

    • Like 2

  8. 20 minutes ago, Stephen said:

    Nice - the more I see the 600XL here, the more I am liking the tiny footprint of it.

    And, in my experience, they are usually in almost new condition. I don’t think they got a lot of use unless someone gamed with them.

  9. What do you think? It has a 576K RAM upgrade. 4 OS ROMs, 8 cartridge ROMs, and UAV.  I am using DIP switches for ROM selection. I have done better with the opening for the monitor jack. I should have taken more pictures before I closed it up.





    • Like 5

  10. On 3/3/2021 at 9:45 AM, DrVenkman said:

     it was the 1200XL’s 9VAC lead, which has the same size plug.

    I did something similar only it was my Indus floppy drive. The display went crazy when on the AC supply and then it went black. Fortunately, it was just the fuse in the 1050 supply that blew. The Indus was fine.

    • Like 1

  11. On 4/21/2020 at 12:42 AM, BillC said:

    The DP4T rotary switch below looks small from the images, unable to confirm but think the pin spacing is likely 0.1". It's the only one I can find at a reasonable price that's easy to mount.


    I bought these and they work great both in size and function. Thanks!

    • Like 1

  12. 1 hour ago, JGRAHAM2 said:

    After replacing both sockets for POKEY and PIA with precision sockets, SIO now works. Thanks to all who helped especially DrVenkman who pointed me to the sockets as the possible problem.

    Well, after putting the aluminum cage back together, it again did not work, so I reflowed the power connectors on both the power supply and the mainboard and it is finally stable and back together with the formerly shattered case. Not perfect, but from the front, it looks pretty good!






    • Like 4

  13. I did find that the socket for the Pokey chip was as you described. The 28 pin would check good sometimes and sometimes not. It was clear that it lacked spring tension. I replaced it with a precision socket. It is acting different, but is still not working. Pin 28 is looking good now. I’ll work on it again tonight with the scope. I was looking at the field service manual on what I should see.

  14. 2 hours ago, DrVenkman said:

    As i pointed out to another person with similar issues, the cassette MTR control line is handled by PIA. Everything used in disk access or any other serial I/O though an SIO2PC, SDrive-MAX, etc is via POKEY. 

    Thanks, that is why I tested with the cassette recorder. I have verified that both Pokey and PIA are good based on switching them out with a spare board and testing there. (Spare board is an 800XL)

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