Microvax II start-up problems after battery replacement

I have a problem booting my microvax II after replacing the batteries in the
bulkhead/connector panel.
Because I didn't get a battery pack, as it was installed before,I soldered
one by myself, with the same capillary joints as the original one. The
voltage is exactly the same as before, only the capacity per battery
increased from 180mAh to 300mAh, which I consider should have no negative
effects.
Having replaced the batteries, the Vax refused to boot, indicating a "C"
Error on the Hex Digit Status Led on the consule bulkhead.
Since I'm not very familiar with Vax Systems I did two things to! solve the
Problem:
First I unplugged the batteries and tried again to boot the Vax.
Unfortunately the problem remained.
Then I thought of having possibly disconnected cables during the battery
replacement. So I completly dismantled all the boards, cleaned them and
checked that all cables are in proper connection to their connectors.
Another attemp to boot ended with the Digit Status remaining at "7"
all the time. All this Error Codes suggest that there is a problem adressing
the rams.
Having checked the connections, what can I do now to solve the problem?
It would be very kind if one could help me and give me some advice what to
do!

Timo