Transmission computer

1993 Honda Accord automatic transmission went out about 190k miles. put in used transmission. It went out. put in another used transmission. When it didn’t work, my mechanic said it was a bad computer. Mechanic found a used computer and put it in. Transmission worked for a few months then stopped working. I have to change gears manually. battery died. put in new battery and the transmission worked!!! but only for about ten days. Now my mechanic says I can disconnect battery cable and reconnect to reset computer for transmission. This works!!! but only temporarily. When computer works, transmission seems fine. I hate to give up on car – 93 Honda Accords are one of best models. Any suggestions? Mark in Irving, Texas.