help - 11/34 console problem -- CNTRL key behaviour

Hi all, just a short question, I have seen so much that I start doubting everything :-( After you pressed the CLR key on the 11/34 console (to get a clear start point), if you *only* press the CNTRL key, nothing should happen, right? [ on my 11/34, when I press CLR (release it), the press the CNTRL key (only that one), the 7-segment displays go all OFF, and when the are on again, they show the value that was in them before I pressed CNTRL. Also, BUS ERR goes on. ] I checked the signals. That the displays go blank is logical, because the DRIVE1 thru DRIVE6 signals remain '1' for 400 ms. But that is the result ... what is the cause ...? - 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.