CA-PSU issue after switching off.

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Don't Panic. Please wash hands.

    Hi there,

    I have just purchased a CA-PSU for my A1200 and while it appears to work great, I am experiencing a strange issue in that the DC-DC converter will not switch back on once I have turned it off, even after waiting for several minutes.

    The only way to get it to power back up is to unplug it from the back of the Amiga, and when I plug it back in, it will work again.

    Once it is on it appears to be rock solid, until I switch it off. At which point it needs to be disconnected from the Amiga to work again.


    I am unable to test the unit on another Amiga and this is the only one I have and was just wondering if anyone had any idea what could be causing this behaviour?

    Please describe the whole setup, especially interesting is what other devices are connected that might be the cause of current flowing when its not supposed to (eg HDMI converters).

    Thanks for the reply, that was fast.


    It appears to be related to a cheap RGB scart to HDMI upscaler that I had connected. (product link removed - please do not post links to companies that are known to treat their employees unfair)


    I had installed the Indivision AGA MK3, but kept the converter connected as it was sending audio to my soundbar, and while testing I discovered that when the RGB upscaler was disconnected the problem vanished.


    So I have connected the audio directly to my soundbar and removed the HDMI converter and everything is now working as it should, so a simple fix in the end, but it's nice to see that support is there when I need it.

    Keep up the good work :thumbup:


    p.s.

    It is early days, but despite trying my very best, I have been unable to get a normally temperamental Amiga to crash tonight. My A1200 appears to be as reliable as I remember it being decades ago. ^^

    Quote from billyad2000

    It appears to be related to a cheap RGB scart to HDMI upscaler that I had connected.

    Looks like the typical problem: Someone decided that saving on a few-cent-diode is a good idea. This may be happening because the TV/monitor is feeding power back into the Amiga through the HDMI converter. This may ultimately lead to damage, so the best practise I can recommend is to cut off all cables from the unit and put a big label on it that says "dangerous to classic computers".


    The most interesting part for me is to see that all the protection circuits I have added to the design even do a job outside their intended purposes. I assume that the 6-second-timer constantly re-starts while it is seeing that voltage level has not dropped low-enough to raise it again. In a way, the CA-PSU became a diagnostic device in this case, without me really intending it to be.


    Quote from billyad2000

    It is early days, but despite trying my very best, I have been unable to get a normally temperamental Amiga to crash tonight. My A1200 appears to be as reliable as I remember it being decades ago.

    What a difference proper regulation and low ripple can make :-) Would you care to list the expansions of your computer?

    Quote from Jens

    This may be happening because the TV/monitor is feeding power back into the Amiga through the HDMI converter. This may ultimately lead to damage

    This scares me, because I have connected my Indivision AGA MK3 via HDMI to an HDMI splitter. Is there an easy way I can check whether my HDMI splitter feeds power into my Amiga through HDMI?

    Quote from sebastian_bergmann

    This scares me, because I have connected my Indivision AGA MK3 via HDMI to an HDMI splitter.

    No need to worry - Indivision AGA MK3 has the required diode in place. It is impossible to feed power back into the Amiga through Indivision AGA MK3 - just like the specifications demand. These specifications have been made for a reason. If everyone would follow them, we'd have a lot less problems.

    Quote from Jens

    What a difference proper regulation and low ripple can make :-) Would you care to list the expansions of your computer?

    Not many at the moment, I bought this A1200 in March, along with 8MB fastmem and an IDE CF converter, and it didn't run reliably.
    I recapped the motherboard, but the problems persisted. I suspected the PSU, and wanting to keep the original PSU appearance, I replaced the guts with a Mean Well RPT-60B and this did seem to fix the issues I was having, at least until I bought the Indivision Mk3 AGA.


    I have to admit, that my initial thoughts were that the Indivision was just plain faulty, it was largely unusable. Then followed more research and I again kept coming back to the PSU as the issue. I also watched the video presentation by yourself which highlighted the unsuitability of the Mean Well as a PSU for the Amiga. Anyway, I thought I would give it a final throw of the dice and ordered the new CA-PSU along with an ACA1221lc.


    Thankfully this seems to have done the trick, and the system appears to again be working flawlessly, even running the ACA1221lc for hours at 40MHz had no effect on the stability.

    I do intend on upgrading further, there is something very appealing about the Amiga, and I never would have dreamed that even decades after I had originally owned one, there would be so many options for upgrading :)

  • 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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