About 6 years ago I picked up a matched set,Technics SE-A3 amp with a Technics SU-A4 preamp.From their Radio & Broadcast series,TOTL back then.The left channel on both went out shortly after purchase.....yeah,got hosed on the deal.Both are pretty rare items,not a lot out there on the web concerning them.I am real impressed with the build quality,and servicability,of both.Excellent design/component layout work.It peeled apart like an onion,service access to everything I needed to get to.Parts used were top notch also.I started with Adrian Kingstons web page on the SE-A3,only info I could find.The proprietary DLPT package outputs are NLA.Evidently they had a high failure rate,even when new.These just took a bit longer to fail.I used his idea on the Toshiba 2sa1987/2sc5359 (B&D Enterprises) output transistor pairs.I had to cut and jumper the pcb (E/B) traces to fit one of the pairs.Mr.Kingstons website says the 2SC5359s need modified.I found the 2sa1987 PNP traces needed jumpered.The 2sc5359 NPN were a direct fit.I shrink wrapped the ends of the jumpers to prevent the insulation from dissolving into goo and so that I could manipulate them with needlenose pliers.I replaced the outputs for both channels.Had to do the layout work to adapt the replacement transistors in,drill and tap the heatsinks and make sure everything aligns.Instead of regreasing the outputs I used Aavid aluminum oxide pads (TO-3PL case type),Mouser pn 532-4180 (?) for thermal conductivity.Very happy with them so far.I also replaced some driver and support board transistors that had failed and some 'lytic caps that were giving unstable ESR/DCR readings.Took quite awhile to dial it in.Just sounds lovely now....and runs a lot cooler.I leave the case top off to aid cooling,and 'cause I like the look 
The SE-A3 amp makes a PL700 seem in the featherweight class as far as physical weight goes......sure got tired of wrestling it around on the work bench.My cardio exercise program was successful
The SU-A4 preamp had some odd issues.A lot of cracked solder joints,and not in the usual locations (inputs/outputs and control areas).These were mainly in the center of the mother board.I backed off the tension on the board mounting screws and the motherboard settled audibly.Evidently the chassis had flexed somehow over the years,binding the main board and stressing the solder joints.All is well now.
Great to listen to them again after all these years.Onwards to a WOPL project!
Lee
The SE-A3 amp makes a PL700 seem in the featherweight class as far as physical weight goes......sure got tired of wrestling it around on the work bench.My cardio exercise program was successful The SU-A4 preamp had some odd issues.A lot of cracked solder joints,and not in the usual locations (inputs/outputs and control areas).These were mainly in the center of the mother board.I backed off the tension on the board mounting screws and the motherboard settled audibly.Evidently the chassis had flexed somehow over the years,binding the main board and stressing the solder joints.All is well now.
Great to listen to them again after all these years.Onwards to a WOPL project!
Lee
! The OP hasn't been on the forums since April of last year, you are in luck though!! We have a plethera of very fine techs, hopefully one will take on your Technics...It's a great amp, well worth getting done right...I'm jealous! It's been one of my favs for many years now!