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xrbrevin

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Everything posted by xrbrevin

  1. I have a TL866 and ive occasionally used that feature. altho, it has never found a bad 74LS thus far so im unsure if its accurate...
  2. Might be worth trying another screen first if you can, just in case the cable is good
  3. Thanks for the suggestions. I have a logic probe and the back of the RAM board is accessible so i'll have a mooch about. I thought maybe i would take a macro photo of the PCB and then zoom in on the computer to check if any traces are in amiss. On the 32k board I did some continuity testing across the DRAMS and all lines appear to be behaving as they should. All address lines are linked, -5v 12v 5v and GND are linked with no crossovers. RAS and CAS lines are linked but only on every other chip, i assume this is due to it being 2x16k on a single board. If the worst comes to the worst, i will salvage the 4116s and make my standard Atari RAM board into a 32k one. These '80s aftermarket PCBs dont have a silkscreen and the traces are less than robust!!
  4. Can anyone give me any pointers as to how to diagnose a 400/800 RAM board? I have a 48k one and a 32k one and i feel ive done all that i can with them but I just keep getting the red/brown screen. ive checked traces for continuity where there should be and shorts where there shouldnt be. Ive checked the 4116 DRAMs work in a standard board and ive checked that the 4164 DRAMs work in an XL. The 48k one receives it's SEL4, SEL5, A14 and A15 connections from the Z103 socket (via a small piggyback PCB) and it also gets the RD4 and RD5 from the cartridge socket (via 2x wires). Does anyone know of a procedure for troubleshooting? Im wondering if the 74LS glue logic is at fault. cheers!
  5. Tracopower is a good make: 5v: https://www.ebay.co.uk/itm/TRACOPOWER-TSR-1-2450-CONVERTER-DC-DC-1-Output-5-W-5-V-1-A-Fixed/171119461528?epid=149085216&hash=item27d783c498:g:XP4AAOSwgQ9ViYN9 12v: https://www.ebay.co.uk/itm/TRACOPOWER-TSR-1-24120-CONVERTER-DC-DC-24V-12V-1A-SIP/171948241143?epid=149091254&hash=item2808e9f0f7:g:vCkAAOxyXzxTIip~ you can also get cheaper ones from china if you like
  6. they work fine, ive done a few now and as Mytek said, no heat! 😎
  7. you should be fine, ive used files from atarimania without issue give it a go! here is another great site - with a "download all" option! http://www.mushca.com/f/atari/index.php?idx=0 😁
  8. i plan to do an AV mod to the machine first, then i will tinker with the 32k board. i will reflow all contacts and if that fails i will desolder the ICs and test them in a (socketed) 16k board shouldnt be too complicated to get it running, no other mods are needed on a 400 unless you exceed 32k.
  9. yes good idea, and use tweezers to lift out the remains of the cut pins
  10. Be patient when desoldering XE PCBs - make sure the chip pins are loose before you prise the chip up. Some were built at a lower cost and their traces can easily lift.
  11. here is an unbranded 32k board using 16x 4116 chips. I obtained it inside a 400 but sadly it doesnt work.
  12. here it be: http://www.mushca.com/f/atari/index.php?idx=H
  13. i refer to this type as: "a can't help getting hit game"
  14. an OS ROM fault can be diagnosed by booting a star raiders cart - if the game works then the OS ROM is moody
  15. ah apologies, i misread your post. i thought you were referring to his AC power supply, not a theoretical DC one
  16. this is why the 400 and 800 have an internal power board.
  17. would look good in a 3d printed case - in beige and orange!! 😎
  18. lotharek products are very good, you wont be disappointed!
  19. Thanks for the replies, I was considering it for my LDW Super 2000 drive. I can get some parts of the Indus GT Diag software to work but RPM and track zero testing does not function properly. I didnt realise that the RPM tool relies on a reflective sticker, i thought they were the same as those temperature laser guns but now i know otherwise. thanks for all the info
  20. As per the title, has anyone ever used an automotive laser tachometer tool to measure disk drive RPM? examples:
  21. xrbrevin

    error

    apologies, i posted this in the wrong category. can admin please remove? thanks.
  22. I have been asked for more details about the LDW DC PSU mod so i thought i would add it here for the benefit of any future enquiries. 1. Remove the 2x rectifiers (RB5 & RB12) and the 2x voltage regulators (RG5 & RG12). 2. Make 2x PCB cuts marked by the pink lines in the image. 3. Add 2x wires as shown in the diagram from just above the cuts to the output pins of where the voltage regulators used to be. (I have colour-coded both wires to show where to solder them - red asterisk is the 5v, yellow asterisk is the 12v.) 4. Attach your DC-in wires at these points the in order to keep the power switch functionality. Red is 5v, yellow is 12v and black is GND. Thats it!
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