Yes, both boards. (I had not seen this video, but the other one was very helpful.)
However…out of curiosity I metered the bias (voltage) on the heads and found that the flex-cable connections to three of the digital play heads, and the bias coil, were open. This may have been partly due to insufficient care taken when I put the FFC back in the connector, and partly due to the end of the cable having delaminated, possibly because of age and/or cap leakage/moisture. This isn’t going to be easy top repair…