Aca 1233 - weird power issues

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Don't Panic. Please wash hands.

    Hi

    I recently got myself an aca 1233 40mhz card second hand and am experiencing odd issues on my a1200.


    With the card connected and power is connected and i flick the switch i dont get any power to the amiga. No green light, nothing.


    i have put contact cleaner on the aca1233 connector and cleaned my a1200 expansion pins all shiny.


    if i reseat the card sometimes it powers up with the card detected . Then after a while running a demo on a loop and exit out of the demo the power is lost and i cant even turn back on again as the power supply stops giving the amiga power.


    i tried thr original a1200 light piwer supply and also a replacement psu. Difference with the replacement psu when i try it is when no power goes to the amiga the light on the psu just flashes..


    is something shorting out causing the amiga to stop powering up until board is reseated? Or is my psu not giving the amiga enough power?


    i also have an indivision mk3 in there and a gotek. It has 3.1 roms and is a rev 1b board.


    machine works ok with no expansion in , and also with a less powerful aca 1220 at 18 mhz in there..


    just hoping its not the card thats the issue


    any suggestions greatly received


    tim

    Not sure if you can tell if the ACA1233 has a defect or not. The stock "light" A1200 PSU is surely too weak for a setup with ACA1233 and Indivision AGA MK3, so if you can, please try without the flicker fixer and see if you get a similar behaviour.


    The "replacement" PSU may be unsuitable for an expanded Amiga. What type is it?


    Jens

    Thanks for the reply Jens


    The replacement psu is this -attached

    At the moment ive plugged in my original light commodore power supply after reseating the card and pulling it out about 1-2 mm so not pushed all the way in to the expansion socket and ive had it running for 4 hours and switched it on and off a few times, run a few demos and games and its still currently on. Im not holding out hope it will last long , but its the longest its been working so far. With so many variables its tough to work out root cause.


    im aware you dont recommend the replacement psu i have - would your psu you sell in the shop have enough power to power my 40mhz aca 1233 40 mhz, flicker fixer and gotek and CF card if i got myself one? At least then im ruling out power delivery as being the cause.. as i do t want to risk screwing up the flicker fixer by pulling it off the chip. Its on there firm and snug..


    regards

    Tim

    Quote from Tj1978

    The replacement psu is this -attached

    That's a known-bad model using a MeanWell Chassis. It's known-bad because while the chassis is OK, it does not know that the load is "at a distance", so it regulates voltage *locally*, not accounting for the cable drop, the connector loss and the filter drop inside the computer. Further, the ripple voltage is pretty high for this one, so it violates three out of three key specifications that Commodore has put out for power supplies.


    You should absolutely return this unit for false advertising. It is not suiatable for an expanded Amiga, and we've had numerous cases of "CA-PSU solved this weird issue" in this forum. I have more to say about this specific seller, but that may count as "throwing dirt", so I stick to the technical facts, and the legal issue that is created with this false advertising.


    More info: http://wiki.icomp.de/wiki/Powersupply_FAQ


    However, in your case, you may be looking at a mechanically damaged ceramic capacitor on the ACA1233. This card is almost ten years old (it's the original red one that still identifies as ACA1232, right?), so it may well be that a micro-crack in one of the capacitors causes a short. Take a *very* close look at the large caps first - they are most prone to mechanical damage. These caps are easy to exchange, even for hobby-level soldering. I would expect quite a tedious search for the cap that's at fault, but a quick repair.


    If you have a camera with a "Macro" setting (mostly depicted with a flower), I can help inspecting the caps. Also, look for tiny dents on the board corners - that would be an indicator that the card has hit the ground from some height.


    Jens

    Thanks Jens

    I will turn over my a1200 later and get some pics over on the caps. Was stable yesterday after i reseated the card and pulled the card back 1-2 mm - i read a1200s prefer that expansion cards are not be pushed all the way in and pulling them out a little provides better contact with the pins- is this something you also agree on?


    Just to clarify, is your own Psu that you sell more powerful than the light commodore 1200 that i am currently using and sufficient to run flicker fixer and aca 1233 at same time? - yes my aca 1233 is an original red board but i dont know what it identifies as ? do you mean if I run the acatool-status?


    best regards

    Tim

    Quote from Tj1978

    i read a1200s prefer that expansion cards are not be pushed all the way in and pulling them out a little provides better contact with the pins- is this something you also agree on?

    Yes, that's correct. Reason is that the A1200 main board is not chamfered properly, and pushing the card all the way in will push the contacts outside, away from the contact pads.


    Quote from Tj1978

    Just to clarify, is your own Psu that you sell more powerful than the light commodore 1200 that i am currently using and sufficient to run flicker fixer and aca 1233 at same time?

    Yes, the CA-PSU is a 60W solution with up to 40W only on the 5V rail. The A1200 unit is rather weak with only 15W on the 5V rail. However, it's not about the total power - that's fine with almost all "new" aftermarket PSUs. The unit you have there provides up to 20W on the 5V rail, which *should* be plenty for your setup. However, it's not cabaple of regulating the voltage depending on the load, taking cabl/connector/filter losses into account. So far, only the CA-PSU has implemented this level of regulation, and all other solutions that I have measured are dropping off with higher load.


    Jens

    Hi Jens

    Thank you.

    I have pre-ordered your ca-psu so looking forward receiving it.


    At least then i know i have got good power quality into my a1200 and can then rule that out, and have confidence it can supply enough power to my expanded amiga.


    If i still end up with issues i know to look elsewhere. In the meantime i will try and get macro pictures of the capacators. I know the card is now 10 years old , but a brief inspection of card it looks good with no noticable damage to any corners.


    Thanks for your advice so far

    Regards

    Tim

    Hi Jens


    Your power supply arrived! Thanks

    Having plugged it in and used it for some hours yesterday my a1200 booted up fine every time and so far everything is stable.


    Plugging in the previous power supply for comparison i immediaty noticed it took my machine from stable to unstable as i started getting glitches where it wokred for a bit but then after a soft reboot my machine just had a black screen with a green light and wouldnt boot up ..


    suffice to say im fed up with the old supply and its now gone.


    Now i can enjoy a stable a1200 - your aca1233 - it might be almost 10years old but its working perfectly now…


    cheers Jens

    That's great feedback, thanks. Please let your Amiga friends know (Facebook, Twitter, Instagram?), as power supplies have always been a delicate topic: My explanations are mostly technical, but they are perceived as slandering other products.


    Your personal experience is a good example that I'm not badmouthing others, but just plain provide the better product.


    Jens