My very first modem was an Avatex 1200 connected to my trusty C64. Unfortunately, the power adapter has long since been, let's say, disassociated from the hardware. I probably still have it, but the trick is that there are no markings on the modem, nor can I find any details in the user's guide, that explicitly state what voltage and polarity the modem expects.
Usually this information is documented somewhere, but the only thing in the user's guide is "Power: 120 VAC, 60Hz, 8W max, with supplied power adapter which is UL/CSA approved".
I do have an adapter that I think has an above average chance (say, 55%) of being the right adapter, mostly because of it's location where I found it, and because it does physically fit the modem. It outputs 9v 200mA center positive, which is very possible, but I don't want to fry this modem giving it the wrong voltage or polarity.
Does anyone have one they could look at to confirm the specs? Or even a good photo of the adapter that is readable?
I did find one very grainy photo of the power adapter where I think I was able to make out "Output: 12v AC". Working on that info, I went back to where I found the 9v DC supply and indeed, found a suspicious 12VAC supply that would also fit the modem. So now, I have two possibilities.