ACA1233N

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  • I recently purchased an ACA1233N and read in the icomp wiki page for the card of the timing issues. While the new card can compensate for the timing issues, it recommended that the problem capacitors still be remove. Does this mean, along with E123C and E125C, that E121C and E122C should be removed as well?


    -John E. Bielak-

  • For starters, please only remove E123C and E125C. Removal of E121C and E122C is only required in very few cases and should not be done in a single step.


    Should you not be able to gain full stability of your A1200 main board with an accelerator (of any brand, that is!) by removing E123C and E125C, you should start by removing E121C, and leave E122C in place, then do extended tests. One very good test for stability is the AIBB "TGtest" where lots of blitter activity is interleaved with CPU register accesses.


    For any modification you are planning to do, the prime directive should be "never change a running system". Only remove components if you really find an instability. It is unlikely that your ACA1233n requires board modifications at all.


    Jens

  • Hello when I put my ACA 1233 card in my Amiga 1200 I have a black screen how can I repare that thanks

    Just follow the hints in the manual: Please pull back the card by 1mm and try again. Some A1200 boards do not have a chamfered board edge on the 150-pin connector, which is why this has been a "standard" way to get an A1200 accelerator to work - not just ours, but all other accelerators as well.


    Jens

  • First of all, installing an FPU is not covered by product warranty or official support. With the high amount of fake chips out there, we strongly recommend to not do this modification.


    Burst mode is switched on/of with the "CPU" command of the OS. To enabe full caches and burst, type:


    Code
    1. cpu cache burst

    To switch off burst, but enable cache, type:

    Code
    1. cpu cache noburst


    You may want to check if your FPU has clock: Either close the solder-jumper labelled "FPU clk" (this will clock the FPU at 40MHz), or install a canned oscillator at place U13. Using the canned oscillator, you can run the FPU at the speed that it's rated for, independent of the CPU frequency.


    Once again, this modification voids warranty of the product.


    Jens

  • Jens,


    I know adding fpu isn't covered under warranty but anyway, what type of oscillator should be used? i noticed different voltages. Can you point me to the right 40.000/50.000 dil8 and dil14 ?


    kind regards

  • The oscillator should be a 5V type, as the voltage on pin 14 is hardwired to the 5V plane. You can even skip on the oscillator and close the solder-jumper, then the FPU will run at the same frequency as the CPU. However, you MUST NOT install an oscillator and close that solder-jumper at the same time, as this may break the CPLD on the card.


    I really don't want to recommend a specific type of oscillator, as this would truly go beyond the "no support" policy.

  • Thanks Jens,


    Well, the FPU is rated at 50.mhz, so i thought adding a DIL8 50.mhz Oscillator.

    I don't mind break warranty on the card. If the 55mhz card was still available, i would have bought it.


    Thanks for your light speed reply though!