Posts by blark

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Don't Panic. Please wash hands.

    The original A500+ RTC was M6242B, the one I have has a RTC72421B (drop in replacement with crystal, so crystal is not populated). I pulled the RTC chip just incase it was causing problems anyway, didn't change anything.

    The meter was calibrated by Keysight, I just got it and the certificate of calibration.

    Either way, I'm using the original PS - I just said I ALSO had a Meanwell that I tried.

    I have tested both systems at length with DiagROM and AmigaTestKit and there are no errors. I pulled out all expansions for fear it was one of them causing an issue.

    The A500+ is stock, save for using an RTC72421 instead of the older chip. 1MB of ram on the motherboard, 8375 Agnus, v2 (37.175) Rom.

    The A500 (rev5) is stock, except for a 8372a Agnus, v1.3 ROM (don't have exact ver).

    About the power supply. The Meanwell is fine for my use, I have a very accurate multimeter (Keysight.. five decimal places) which was recently calibrated. I have adjusted the trim pot and the Meanwell is like 4.99999 on the 5v line at the Amiga LF1.

    I see that according to the wiki:

    > Blinking once, pause, repeat: Success, all ok

    However, each time I boot from the rescue disk, after about 30 seconds it starts blinking a single time. But the screen is black. I am using the same monitor and power supply and all other configuration is the same as it was before. Note: I have tried several rescue disks.

    Please help, my indivision is dead at this point. Thanks.


    I have an issue with my Indivision ECS V2. I attempted to update using the latest rescue disk on the site, the screen went blank and the power LED began dimming every couple of seconds.

    I left it for what seemed like a really long time, as I wasn't sure if it was flashing or not as the screen is now blank. Eventually I powered down and now my Indivision is not displaying any picture.

    How long does the flashing process usually take? Is this power LED dimming/flashing normal? Thanks for your assistance.

    My setup: A500+ 1mb chip ram, no mods present beside Indivision ECS v2.

    Jens I'm afraid that I have brought shame upon myself by hastily plugging the aca500 in upside down. Can you please let me know which resistors I need to swap? Thanks.

    EDIT: oops, nevermind I found the silkscreen pointing to them near the edge connector.

    Thanks for the clarification Jens your time is appreciated!

    I did read the wiki, several times. I even tried to search for "chipram" to make sure that I wasn't missing something. I think that the wiki would benefit from a bit of additional clarification so that folks like me are _absolutely clear_ how to set up their aca500plus in this scenario.

    Could you please clarify for me the three settings I mentioned earlier:

    • $C0/Trapdoor RAM
    • 7M Fast RAM
    • 1M Chip RAM expansion

    For a 1meg chip ram setup, what *exactly* would these be set to? I am not sure what you mean by "No need to mess with $c0 memory"... does this mean I leave it as default, turn it off, etc? So you providing the exact options for a know-good 1meg chipram config would help folks experiencing problems (like bad memory) rule out aca500plus config as the reason.

    Thanks very much!

    Jens thanks. So, to be clear, on a rev 5 motherboard all that needs to be done to get 1 meg of chipram is to:

    - replace Fat Agnus 8371 with an 8372A,

    - switch on the chipram option and turn off $C0/Trapdoor RAM in expert settings

    Can I suggest that you make a note about this in the Wiki? As far as I can see it's not documented, and it might help out anyone in my situation in the future.

    Edit: One last question, would there be any problem on the aca500plus with flashing the DiagROM so I can test the memory expansion I have?

    Thanks very much.


    I have my aca500plus connected to a rev 5 motherboard. I have an amram-x 512kb expansion, and an 8372A Fat Agnus and decided to give upgrading to 1mb chip ram a try.

    I have cut JP2 and soldered the top pads as per instructions on the net. According to what I'm reading all I should need to do now is turn the amram-x to "off" and it should be detected as chipram. However the aca500plus lists the ram as "unavailable" when I do this, when I turn it on and boot the Amiga it sees the ram as built-in (forget the exact term) and boots fine. I have _not_ cut the line near the trapdoor (EXRAM) because I from what I read the off/on switch on the Amram-x should take care of that.

    However, I am having some issues with the upgrade as it seems that SysTest (crashing) and other utilities designed to check memory are finding errors. I was hoping to confirm the proper settings for this configuration so I can 100% rule out a configuration problem and move on to hardware troubleshooting. I am wondering what the various ram options should be set to? Currently they are (with the ram switch ON - because OFF == aca500plus doesn't see ram)

    • $C0/Trapdoor RAM: disabled
    • 7M Fast RAM: max
    • 1M Chip RAM expansion: built-in

    I read somewhere that I might need to make a modification related to the ROM (apparently EPROM based ROM chips require extra wiring), but I am not 100% sure what to do about this since my ROM is technically coming from the aca500plus.

    Any help or insight you could provide would certainly be appreciated. Thank you!

    Ok, I think I figured it out, the key was in this sentence of the above doc that I posted: "Note that only the P9B pins 19-40 actually have a header soldered in in most machines"

    This seems to make sense because the header is 22 pins... Jens is this correct?

    Jens so I finally have a resolution to my issue, as it turns out it was the bent pins (pictured in my second post) causing the problem. I assume they were not making contact with the Amiga.

    I wired up the new RT-65B power supply (tuned the 5v line under load) and again had the same "black screen" issue as before. Disappointed with the result I decided to try to bend the pins back into shape. I used a pair of very fine tweezers that I use for SMD soldering to bend them as close as possible to the other pins. I used a pair of 3.5x magnifying glasses to make sure that I wasn't shorting anything out.

    Sure enough after re-seating, the card worked immediately. I'm very glad to finally have the issue resolved, and have my aca500plus working!

    KKR75 thanks for the feedback, looks like the RT-50B and 65B are very similar. The 65B just has a slightly higher rated current output... Shipment was delayed again, should be coming in today so I will have a chance to hook it up and test it out.

    Jens the power supply shipment was delayed until today. I do happen to have some 1000uF 50v caps here that I will try on the 5v line. I'll also measure the voltage to make sure that it is stable at 5v. I anticipate trying all this today, I'll report back soon.