Aca1233n black screen A1200 rev. 2b with no problematic capacitors

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  • Good evening, I bought an ACA1233n card with order number 57472 dated 22.05.2019 and when I go to connect the card to my Amiga 1200 I get a black screen (I can't even access the early startup screen). Point out that the Amiga 1200 motherboard is a rev. 2B and therefore seen problems I completely disassembled the A1200 to see if there were the capacitors that are recommended to eliminate E123C and E123C. To my surprise they are not present nor present even the E122C and E121C (if you want I send you some photos). Since the Amiga1200 works perfectly without the ACA1233n card in this point it is faulty and I ask for it to be replaced.

    Greetings.

  • Please follow the first-aid-steps described in the included manual: If you can't get it to work on first installation, just pull back the card by 1mm, so a different part of the contact area of the A1200 is used. This has been a common fix ever since A1200 trapdoor-expansions existed, which is why it's mentioned in the printed installation instructions.

  • Please follow the first-aid-steps described in the included manual: If you can't get it to work on first installation, just pull back the card by 1mm, so a different part of the contact area of the A1200 is used. This has been a common fix ever since A1200 trapdoor-expansions existed, which is why it's mentioned in the printed installation instructions.

    I did further tests as instructed, moving the card mm by mm and cleaning the contacts where the accelerator card should be inserted with a pencil eraser, but to no avail. The only thing more that I had not indicated and that the reset via CTRL + A + A is performed but you can't get to the boot screen. An additional assumption is that it could be a power supply problem, even if no indication is given in this sense, it is that the power LED has a lower intensity when the ACA 1233n is connected. I have the original 25 Watt Commodore power supply 5V / 3A, 12V / 0.5A, -12V / 0.1A, black if it can be useful. However, the idea remains that the ACA1233n sent is defective.

    Greetings.

  • Each accelerator is tested before it gets it's warranty ID, so a "dead on arrival" is *very* unlikely, as the test is pretty thorough (even the CPU is separately tested before it's assembled, then the complete thing is tested before it's labelled and packed).


    Please take a close look into the white CPU connector: Can you see any bent pins? You may have one of the rare A1200 boards that does not have a chamfered edge, where it's necessary to pull out the card even more. We've had a case before where such an A1200 board has damaged a CPU connector.

  • Each accelerator is tested before it gets it's warranty ID, so a "dead on arrival" is *very* unlikely, as the test is pretty thorough (even the CPU is separately tested before it's assembled, then the complete thing is tested before it's labelled and packed).


    Please take a close look into the white CPU connector: Can you see any bent pins? You may have one of the rare A1200 boards that does not have a chamfered edge, where it's necessary to pull out the card even more. We've had a case before where such an A1200 board has damaged a CPU connector.

    This evening I will post some photos of the card of my A1200 rev. 2b and your ACA1233n inserted and not. This way you can take away all your doubts.

  • OK, so the connector of the ACA1233n is OK, and you're showing that the card is inserted all the way into the A1200. Please *really* try pulling it back by 1-2mm - it does wonders :-)


    For final stability, you might want to put the shielding back on - both top and bottom, including all motherboard screws. The computer will start and work without, but stability is improved by the shielding.

  • OK, so the connector of the ACA1233n is OK, and you're showing that the card is inserted all the way into the A1200. Please *really* try pulling it back by 1-2mm - it does wonders :-)


    For final stability, you might want to put the shielding back on - both top and bottom, including all motherboard screws. The computer will start and work without, but stability is improved by the shielding.

    I have already done all the tests with the card not completely inserted that have been shown to me when the computer is closed. I had to take it apart as I was thinking about the timing fix which is not required as the capacitors are already absent. Tonight I remount everything and I do a last test with the ACA1233n partially inserted mm for mm until not insertion, but I strongly doubt its operation since reading on documents the black screen indicates that the CPU is not recognized.

    Are we sure this is not a problem of insufficient power supply with the ACA1233n card inserted? Because I left it 5 min with a black screen and the power supply heats up more than without ACA1233n inserted. How can I test the power supply with the ACA 1233n inserted? The ACA1233n does not remain cold when it is inserted but it also warms up after 5 minutes.

  • With practically no other peripheral in your computer, the original 3A PSU is absolutely sufficient. The LED being a little dim when powering on is a property of the Amiga - it will be set to full brightness by the software once the processor is executing the first commands from Kickstart.


    If your tests aren't successful tonight, just send the board back for service - that's what the warranty is for.

  • Please send it back to the company address, including original packing and manual.

    Do I send to this address also attaching the conversation on the forum?:

    Individual Computers Jens Schönfeld GmbH

    Im Zemmer 6

    52152 Simmerath

    Germany