have a master spa exetor II. thought the top side control was bad because we are unable to control temp(stuck at 100f) but the light and jets buttons work properly. tried replacing top side(on master spas recommendation) and didnt work. then was told to try circuit board (part #x800660) so purchased it and apparently its not exactly the same. it doesnt have a connection from the heater fuse to the relays. everything else matches and is able to connect but that . please see pics. 1st is the new board...second is the original. i did notice that the original is "mas25r1a" and the new one and all the other boards i can find are "mas25r1b". was thinking that was it but cant find the "a" model. any help is very much appreciated! thank you!

Your photos are excellent (actually perfect), but...

Back off. Post a photo of the entire box internals.

Nobody can diagnose your particular situation with a macro close up of a couple of relays on a circuit board.

Try again please.

The thing you want to look for is the revision of board, your original board is a MAS25RIA, the IA (1A) at the end is the revision. As long as only the A changes to a higher letter can you use the board. If the I (1) changes to a 2 you cannot use it.

sorry about that ........is this any better?