ACA 500 plus suddenly stop working

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Don't Panic. Please wash hands.

    Hi,

    I have bought some months ago a used ACA 500 plus that worked flawlessly... Until now.

    Previously I tried it with my a500 and a500+ and with an amiga 500 of my friend without problems. Tonight after a reset after setting the CPU clock to 42mhz to try this speed all worked fine for some minutes then the Amiga resets and boots no more. The digit display is stuck with a 20 and the led is blue. Also the screen is blue and if I try to enter debrik mode I get a 0_ but doing a reset with CTRl a a does nothing. If I wait some more time the dismo changes to 8.8, the led is turning bright white and the amiga screen is displaying something like copper effects. What should I try to do? I think the a500s are not the fault as previously all the three amigas was working fine with the card now they are all bricked with the ACA. Obviously if I remove the card the 3 Amigas are working fine.i tried also swapping PSUs (2 originals plus one recapped) with no luck Any suggestions? Thanx!

    This sounds like a contact problem - if you see the DisMo changing and some "effects" on screen, the CPU is running, possibly even trying to execute the exception handler.


    Overclocking will only be activated if you leave the menu, so you have the possibility to reduce the max. speed before you launch next time. Just try cleaning the 86-pin contact with a micro fibre cloth and IPA (should be available from your local pharmacy). Do not use contact sprays, as they normally contain lubricants that you don't want on this connector.


    The ACA500plus side can be cleaned with an old toothbrush and IPA. Do not let it dry, but attach to the computer while still wet. It'll evaporate in a matter of seconds.

    Hi! Unfortunately the situation hasn't changed. I've tried cleaning carefully with isopropylic the ACA and the connectors of my 2 Amigas+ the 500 plus of my friend but the error is the same with screen going crazy with multiple colours and copperlist like effect. It's very unlikely a problem of the 3 Amigas that as yesterday were perfectly working with the aca. Is there something else I could try? Thanks again

    There's nothing hot after running 5 minutes not on the component side nor on the dismo upper side of the board. The only thing hot is the led near the dismo that's running bright white... ;-(||

    Ok, so no other options to try;-(. I have to evaluate if it's convenient to pay the courier to and from your factory, plus the price of the reparation or if it's more convenient to buy a new one. I bought the card used only some months ago and I don't have the invoice to know if it's still covered by a warranty. It's a 6a version 2018 model is there a way to know if it's covered by a warranty for e.g. with a serial number? Thanx again

    If this is the "big dismo" model, then it has the "resistors of shame". Your description sounds very much like it's been connected the wrong way round, and in that case, only the 22R resistors burn and act as a fuse for more expensive parts (CPLD and DisMo chips). These are close to the edge of the card, and the label "resistors of shame" is hidden under the 86-pin connector's footprint, only visible if you look closely through the exposed pins.


    In that case, the resistors of shame can be replaced with new 22R resistors and the unit should work again. This is a really easy job and it can be done by pretty much any person who knows which end of the soldering iron gets hot :-)


    The team is currently in summer holidays, and I don't have access to the database, but the warranty ID can tell us when it's been delivered. I'm all for saving resources, so we better check the resistors of shame first.

    Thanx!Yes this board is the "resistor of shame" version. I'm more than sure to have not connected wrong side the card but to double check how can I verify if the resistor is ok or burnt? Thanx again!

    Ah I have to mention that the board stops working as it was running on the Amiga for some minutes so it's really not the case I inserted the board wrong side but just to try all possibilities of there is a way to test the resistor please let me know thanx

    Excuse Again me. I'm at home and I'm trying with a volt meter and the 2 resistors are not interrupted the voltmeter is beeping so I think they are ok.

    I have some spare time today. I'm not an expert but im trying to see with the tester if there's something strange on the connector and I have noticed that the first 2 rows of pins (the 2 up and the 2 down starting from the right side of the board with dismo facing up where there's the version of the board t502 V6 12 SEP 2018) are shortened. I mean if I try to touch the legs of the connector I find that they are not isolated but there is contact between these 2 up and 2 down connectors others on opposite are isolated. It's this normal? It's a little bit difficult for me to explain this in English it's possible to post a photo? Thanx for your time.

    Quote from maurensen

    I have some spare time today. I'm not an expert but im trying to see with the tester if there's something strange on the connector and I have noticed that the first 2 rows of pins (the 2 up and the 2 down starting from the right side of the board with dismo facing up where there's the version of the board t502 V6 12 SEP 2018) are shortened. I mean if I try to touch the legs of the connector I find that they are not isolated but there is contact between these 2 up and 2 down connectors others on opposite are isolated. It's this normal? It's a little bit difficult for me to explain this in English it's possible to post a photo? Thanx for your time.

    To post a photo, click on Attachment and Upload it here. Maximum file size is 1MB

    Images

    A1200 Rev2B OS 3.2| SanDisk CF64GB | Blizzard 1230 IV 64MB FPU 68882/50 | Indivision AGA MK3 | CA-PSU | Eizo S1933 | Bose Companion 2 series III

    A500 Rev6A OS 3.2| SanDisk CF16GB | ACA500+ V2 / Blizzard 1230 IV 32MB | Indivision ECS V3 | ACE2b | CA-PSU | Eizo S1933 | Bose Companion 2 series III

    A1200 Rev2B OS3.2.2 | Black Edition | SanDisk MSD32GB | PistormLite32 | Indivision AGA MK3 | RTG Picaso96 1280x1024| CA-PSU | Eizo S1933

    iAmiga 27" | OS 3.2 FS-UAE | SDD 1 TB | RTG Picaso96 2560x1440

    Maybe because in writing on a phone or because I'm not registered I've not an attachment button.... I'll try to register and use a pc

    The Dismo connector is two bottom-entry femalte headers connected with a long-pin male header. The solder points of the female connectors may or may not touch, which is OK, as they are connected through the pin header anyway.


    Yes, guests cannot upload pictures here, but registered users with a few posts can.

    Hi, I sent the board with a letter explaining problems last week. Could you please confirm that you have received the board? Thanks

    An ACA500plus arrived, but do you have any identification, a name, warranty ID? Also, please note that workshop staff does not access this forum. I always have to talk back with them, and it's already past working hours.

  • The last reply was more than 365 days ago, this thread is most likely obsolete. It is recommended to create a new thread instead.

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