ok so let me start with the simple: i have exactly the same board as described here:

http://www.lvr.com/files/mibch3.pdf

i have bild it after that plan.

i don't have EPROM. just the EEPROM (the same as in the source list of the circuit above.)

the problem with the VCC is the following. i don't have a exact 5V Vcc at home. so i tryed the 3 AAs and it worked perfectly. i could write programs and run them. the only problem was that i couldn't use the PROG commands. as far as i know the different PROG commands save the program to the RAM and optionally start it, save the baudrate, etc... so is the RAM in the circuit above enough to save this stuff or do i need a second external RAM piece?

i even thought that maybe the 3 AAs got uncharged and i replaced it with new ones which gave me something like 4.7V

the second problem occured yesterday: i figured out that a personal computer has 5V (5.15-5.16V exactly) power so i attached it to the correct lines at the PC but nothing happend. nothing. the circuit doesn't even boot up. but the LED at the circuit was lightning. was the 5.15V to much?

if i type a 10 PRINT 3 or some other line of "programm code" it gives me an error like "invalid line number" (i cann't remember the exact words but it is pretty like this.)

thanks for your help
rw

PS: there is one PROG X command (don't know which exactly) which saves the baud rate. but for how long. if i detach VCC and reattach it it is reseted, right?