DEC 3000/800 AXP boot problem

Hi, just a quick enquiry. I have aquired a DEC 3000 Model 800 AXP and have a boot problem. The system was booting about once every ten power ups. The status LEDs don't move in the case where the system checks do not 'kick in', they remain on '00'. I have cleaned the entire box and used contact cleaner on all connections, and re-seated the motherboard and IO module. Previously when the system did 'kick in' all tests completed correctly except the keyboard/mouse test. I am using a VT520 connected via an original DECconnect cable. I managed to install both OpenVMS 6.1 (the original disk received with the unit) and OpenVMS 8.3 (although this didn't boot, but probably due to the fact that I selected DECnet but don't have any thick/thin cables connected). Sorry to be so long winded. So the question is, apart from reseating/ cleaning cables/connections, is there anything else I could check/test/ try? I have enough competence to measure voltages and possibly even power ripples and the like, but I don't have a logic analyser. Do the SROMs age at all? It is a standard x512 EEPROM. It has a sticker over the programming window (assuming it has one). Is there a battery backed module that could be causing intermittent problems? Additional information: I intermittently get the following error: ASIC ?? 002 0020 T-ERR-ASIC COREIO address = f0080280 data read = 0 data exp = aaaaaa Code 'EF' is displayed on the LEDs. Does this, and the 'not booting at all' indicate a problem with the SROM/EEPROM? I flashed it recently to version 7.0, the latest, but I think it was having this problem before it was flashed. Thanks, Mark.