Radio Shack 2150
 

Hi, I just wanna mention that comparing to this foto

https://www.schach-computer.info/wik...150Platine.jpg

my device has different platine (see attachment): R65c02-4Mhz (vs 3), newer NEC controller produced 1989 (vs 1988), faster RAM - 12ms (vs 15) and probably faster ROM (marks: AMI 9002MAO; YO1GH; C12E U3).
Also there's an empty slot for additional chip (EGR or RAM?)

AW: Radio Shack 2150
 

CPU speed is not relevant, what is printed on oscillator? 12 = 120 ns, 15 = 150 ns RAM speed. But the difference is not important at 3 or 4 MHz cpu clock.

Re: Radio Shack 2150
 

Oscillator itself is still 3Mhz but I suppose that due to the fact, that all chips are newer it would be possible to replace oscillator by 6Mhz one without re-soldering ROM / RAM / CPU (I hope it would work this way)

AW: Radio Shack 2150
 

It's a Rockwell CPU specified with 4 MHz. It will run with 5 I think. 6 is possible, but not very likely. Give it a try. RAM is fast enough.