Hi all, I finally got juice on the main power line connection in my museum. I am connecting my machines bit by bit, after 2 years of inactivity. I have found the following problem with my 11/34C. (I will keep the description short, and tell only the end result) The console of the 11/34C (11/34A plus cache option) shows weird (=wrong) behaviour. It was working fine! The display shows "000000", and the RUN LED is off. If I press the 'LSR' button, the 'SR DISP' LED goes on. However, if I press any of the numerical buttons, '1-6', a digit in the display only flashes very brief. I cannot say what the digit was. It looks like the M7859 has developed a problem. To make things more weird the following happens if I start with pressing the 'CLR' button and then the numerical buttons. 1) press CLR (display stays at "000000") 2) press e.g. 6 (some of the rightmost digit segments briefly flash) 3) press 6 again (1st and 2nd of the right display flashes) 4) press 6 again (1st, 2nd and 3rd of the right display flashes) The first leftmost three displays remain "000" and do not show any sign of changes. Pressing 6 after the first 3 times, repeats the flashing of some segments in the three rightmost displays. So, I have the impression it has the problem to do with the M7958. AFAIK, the entry of the digits, for example the numeric entry '165020' does *not* need the UNIBUS, but only sets up an internal register. The 'LAD' button, and 'DIS AD' will start a UNIBUS cycle (to access a memory location). Correct? BTW, the voltage on the CPU backplane (DD11-PK) is 5.08 V. and the +15 and -15 read +/-15.x V. (Can't remember the exact value). I have an other 11/34 with an M7958, but never powered up that box. I took that M7859 and installed it in the 11/34C. The display stays dark. According to the M7859 doc, that basically means that the board is dead. So much for board swapping. Sorry, could not resist to try an easy success. I don't have other spare M7859 ... If you are interested, I can tell the steps I did before I stumbled on this M7859 (?) problem ... Anybody seen this display / console panel behaviour on the 11/34 ? Any clues ? All input is appreciated ! thanks, - Henk, PA8PDP. This message and attachment(s) are intended solely for the use of the addressee and may contain information that is privileged, confidential or otherwise exempt from disclosure under applicable law. If you are not the intended recipient or agent thereof responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please notify the sender immediately by telephone and with a "reply" message. Thank you for your cooperation.