Batboard

I have a Spectra that is an A3 HHCH radio, I have a PL problem and I know it is a problem with U400, so I thought no problem, I have more HLN6094B command boards from A5 style radios, I'll simply swap the MLM and reinitialize the board and that'll save me from having to swap the audio filter IC. The problem is that I lose the display and any kind of functionality for the controls on the mic. All I get is F1 and PTT, other than that my experiment went like gangbusters. I visually went over all the components, to see if I missed any jumpers that were different, but I didn't see any. I did my best to search the past posts, sorry if I missed it.

Any suggestions?

While I was figuring out the MLM connections I noticed the Command Board JU505 Load/Shift and JU506 A3 VIP Latch are HHCH functions. JU505 goes to J0502-27 (it appears JU0513 must be removed if it is installed) and JU506 goes to J0502-14 (it appears JU0512 must be removed if it is installed).

Looking at a schematic for the HLN6089A/HLN6097A HHCH Interconnect Board, the P0502-14 A3 VIP Latch does not appear to do anything (it may have an optional connection), but the P0502-27 Load/Shift is critical to the operation of the HHCH.

Sorry, I can't tell you if any other jumpers are different because I've never done this Command Board conversion myself.