Finally looked at #1 today - operator error again... I didn't have 16v caps when I swapped a couple of 47uFs on the servo board earlier, so used 35v items with a higher profile...causing this;
Not a problem when I only had a lossy connection between mech and servo board (I initially used the 2 plastic spacers that slipped over the screws for temporarily mounting mech to servo while fault finding, and it worked fine - but testing again tonight with the 2 tight fit spacers was enough to have the same issue).
I simply refitted the original 16v items and it is back to life
Very interesting to compare the 2 CDIs;
#1 bog standard except for a recap, with a dual crown 1541
#2 with Flea and dedicated PSU, and 4 ALWSRs powering OPA627s instead of stock OPA42s at output. Against it, it is running an R version of the TDA1541A instead of the normal single/double crown version
Both have had output caps swapped for 10uF wet tants.
Objectively, #2 is better in every way. Subjectively I prefer listening to #1
I will leave #1 on repeat for 24 hours, those wet tants take a while to come on song. Logically, I should swap the TDA1541As between players to confirm how much of a role that is playing, but that's a pretty high risk based approach given my soldering skills
If anyone has a single or double crown 1541A, or a Taiwan date code one, they'd consider selling me, please let me know. I'm in contact with Cricklewood, they are running low and have no Taiwan items, but I will buy one of their later items just to see whether the R version has much of a role to play here.
I think I am about to mount 2 disassembled CDIs into my main system permanently to allow me to compare further
Richard