PL700 Rebuild
- Thread starter Overundr1
- Start date
Will fix ground wire attach point, remove the extra wire that was suggested a few pages back and verify e-b-c connections on the 2N5088 thermal compensation transistor shortly 
Lets make absolutely sure I have the control board wired correctly to the backplane. Remember this is the first version of the PL-700 so rather than confuse things lets go with the rca6654's are in all four bottom rows (closest to control board connector), the rest going up to the top are MJ21196's on silipads. Bank 1 is closest to transformer
L1 Input +
L2 input ground
L3 Purple Base of RCA 6654 bank 2
L4 Yellow collector first MJ21196 bank 2
L5 White to buss bar between main caps
L6 open since this is a quasi-complimentary setup
L7 Grey to collector RCA 6654 bank 2
L8 Orange collector of rca6654 bank 1
L9 Brown emitter of first MJ21196 bank 1
L10 Blue base rca 6654 bank 1
L11 Green base first MJ21196 bank 1
L12 Main cap +
L13 Main cap -
L1 Input +
L2 input ground
L3 Purple Base of RCA 6654 bank 2
L4 Yellow collector first MJ21196 bank 2
L5 White to buss bar between main caps
L6 open since this is a quasi-complimentary setup
L7 Grey to collector RCA 6654 bank 2
L8 Orange collector of rca6654 bank 1
L9 Brown emitter of first MJ21196 bank 1
L10 Blue base rca 6654 bank 1
L11 Green base first MJ21196 bank 1
L12 Main cap +
L13 Main cap -
A quick update. With just the first row installed amp sounds great. Added second row (top row to be accurate), amp sounded great. Installed row above driver outputs and amp sounded like ^*&(*& again. This backplane gonna be the end of me. If Joe stops by the thread, does the replacement chassis come drilled for end mount capacitor clamps as the original 700 does not have the transformer saddle.
Am about to remove the entire backplane and see just what the heck is going on underneath those mounts, all of them were really filled with dry thermal grease and most needed to be tightened up as well. As many have already suggested, the beating of one's head against the wall will continue until an entire WOPL is completed
Am about to remove the entire backplane and see just what the heck is going on underneath those mounts, all of them were really filled with dry thermal grease and most needed to be tightened up as well. As many have already suggested, the beating of one's head against the wall will continue until an entire WOPL is completed
A quick update. With just the first row installed amp sounds great. Added second row (top row to be accurate), amp sounded great. Installed row above driver outputs and amp sounded like ^*&(*& again. This backplane gonna be the end of me. If Joe stops by the thread, does the replacement chassis come drilled for end mount capacitor clamps as the original 700 does not have the transformer saddle.
Am about to remove the entire backplane and see just what the heck is going on underneath those mounts, all of them were really filled with dry thermal grease and most needed to be tightened up as well. As many have already suggested, the beating of one's head against the wall will continue until an entire WOPL is completed
Am about to remove the entire backplane and see just what the heck is going on underneath those mounts, all of them were really filled with dry thermal grease and most needed to be tightened up as well. As many have already suggested, the beating of one's head against the wall will continue until an entire WOPL is completed
With the original power transistor sockets, I always remove the transistors and lightly pinch the contacts together with needle nose pliers. Many cycles of on and off heat cycles and pulling/inserting the devices may cause the socket contacts to become loose. This can create capacitance in the contacts or even worse, intermittent continuity.