Hi,

I pulled my AIM-65 down from the attic, and "low and behold", it no longer works. The display remains blank, the printer doesn't "chunk"...it's all quiet in AIM land. .

I have the correct voltages going into the board. My logic probe, the only piece of digital test equipment I have, says I have clock pulses. When I shut down, the printer chunks once. I noticed that several lines on the Data bus are at 2.1 volts- not a good sign. I pulled out all the socketed chips that attach to the bus, but the same data line is at this "no-mans" voltage at the 6502.

The RESET switch has no effect to correct the problem. The Keyboard and RUN/STEP switches are in the correct position.

Any ideas??? Does it look like a bad processor? Anyone have a spare 6502?

Thanks in advance,

Ron

I've been search for a schematic of the AIM-65. I found one picture but it was not readable. If your ROM is in a socket, you could try Lee Davison's NOP generator to test the address bus.

Daryl

Thanks Daryl,

The NOP generator looks like a good place to start. I have all the AIM-65 documentation, and if and when I get the system up and running again, or even if I don't , it will all be for sale on Ebay.

Wish me luck!

Ron

NOP SAVES THE DAY!!

With the NOP circuit attached, and my logic probe in hand, I was able to quickly find a bad 2114 RAM chip. I pulled it out, and the AIM-65 boots up!
Now to find a spare 2114 & make the AIM all better.

Thanks to the Forum.

Ron K

Glad to be of service. 8^)=

Lee.