An update -

Bought a different RAM module but sadly the issue remained. Cleaned the contacts and no luck. Since I didn't see any errors with memory tests anyway, I'm ruling out the RAM being the problem.

I'm really thinking it must be an issue with the Blizzard, but nothing looks obviously suspect on the card. Think I'll have to return it and be patient waiting for another to come up

Thanks all for the suggestions

Everyone can now try the last demo on their Amigas: it's available for download at https://retream.itch.io/ptds.

P.S. If you try it on a CRT, post pictures and let everybody enjoy the view, please!

Check the DC voltage on all of these lines to start with, U3 pins 32, 33, 35, 36.  They should normally be around 4 to 5V when in an idle state.  What you find will determine where to look next.

I first measured voltages on mentioned pins without the mouse connected: pin 32 (P0X): 0.05V, pin 33 (P0Y): 0.05V, pin 35 (P1X): 0.06V, pin 36 (P1Y): 0.06V. Next, I measured voltages on mentioned pins with the mouse connected: pin 32 (P0X): 0.05V, pin 33 (P0Y): 0.05V, pin 35 (P1X): 0.06V, pin 36 (P1Y): 0.06V.
These pins are really pulled low, I tried looking for continuity between them and the ground as maybe they are shorted with it, but they are not.

Maybe something related to the USB serial port, I've seen instances where they randomly stop working, or they do something unexpected such as transmit data working but not receive data; then it starts working again when you disconnect/reconnect the USB cable.

I will try doing that in the future if I won't get anything on PuTTY. Maybe reconnecting the USB will help.

You could sanity check that the data looks valid on each of the 16 data lines and 8 address lines at U3 if you wanted to, that's quick and easy to do with an oscilloscope.

You could always try exchanging U3 with a known good 8364.  It's the same part between A500, A1000, A2000, A3000.

I also did the following:

• visually inspected top and bottom side of my A500 near Paula and joystick connectors - nothing obvious appears broken, corroded, lifted
• looked for continuity between U3 pins 32, 33, 35, 36 and E417 (P0X), E416 (P0Y), E427 (P1X), E426 (P1Y) - they are connected

• checked if RP401 is healthy - getting 9.2kΩ between pins 1-2, 1-3, ... 1-9 and 4.6kΩ between 1-10. I'm getting 4.83V on all of them. I'm not sure if pin 10 is GND (it is according to amigapcb.org's Rev8A), but if it is maybe that explains the 4.6kΩ reading. However, I'm getting 4.83V from pin 10 too, which I suppose suggests that it isn't GND because if it was it would read 0V.

I think that the smartest thing I could currently do is to first check the data and address lines with an oscilloscope and totally replace Paula if needed according to the test. As I'm getting really low voltages from P0X, P0Y, P1X and P1Y, I suppose that something definitely is wrong with Paula, as DiagROM suggested.

I don’t know if I should try checking Paula with an oscilloscope due to bad voltage readings I got for P0XY and P1XY, maybe I should just replace it? If I should, is there a chart online that shows good and bad reading examples for specific pins on A500’s ICs?

-poroxius, September 17th, 2025[/list]

The attachment shows what the back panel looks like...

I had problems with the same setup, which I hadn't used for a while.

I cleaned both the edge connector on the RAM and in the socket with IPA. That helped!

Best of luck with it.