JimH
For what it's worth ....
If I understand your hook up for the two battery test, and the comment regarding discharge ( you seem to indicate that you had no load on the rewired pack when the problem happened ) .... then you have problems.
While NiCads have self discharge characteristics, they do not usually exhibit them in the manner that you indicate !
It sounds like you have cell to cell leakage across the cells within a "Block".
With the way the original pack was configured, cell to cell leakage would be masked as all (-) and (+) connections in a given block are essentially in parallel.
When you rewired the cells you seem to have unmasked that sort of problem.
I would:
1) Remove all links between cells in a "Block".
2) Measure each cell to see if it was the correct polarity and a reasonable voltage.
3) Within a "Block" test from each (-) and each (+) to all other
(-) and (+) connections
You should only show voltage from a given cells (-) to its (+).
If you show a voltage from a given cell's (-) or (+) to any other cells (-/+) then you have a problem with cell to cell leakage within that "Block".
I looked closely at the photos of your original setup and it does not look like there are internal cross connections within a "Block" that would prevent you from rewiring its cells in series.
I realize that it's a pain in the butt, .... but you need to remove all the cross links from all the "Blocks" and test each of the battery blocks.
You may have just had a lucky find and hit the only "Block" that had a problem or you may have problems in several blocks.
A bailout may be to go back to the original configuration and locate an additional "Block" to make up the required 10. This is however, just masking the original problem which will eventually come back to bite you.
Normally you should be able to wire a "Block" in series.
A Google search indicated that NIFE still seems to be around - you may want to snail-mail them a letter requesting info on those blocks. ( I never found an internet site for them. )
From an EPA site that Google found a NIFE INC. ref. in, I found two variations on an address:
NIFE INC
GEORGE WASHINGTON HWY
LINCOLN, RI 02865
NIFE INC
GEORGE WASHINGTON HWY
LINCOLN, RI 02865
Wish you the best on the project - glad its you and not me having to "un-link" all those blocks and test them.
Russ