Realistic SA-2001 good quality schematic diagram
Lavane
Lunatic Member
Just take it slow and easy. There are a lot of screws holding this thing together and a lot of disassembly of the chassis. Take lots of pictures as you go. And be mindful of capacitor orientation. Some of the + and - marks printed on the boards may be backwards. Make a make with a sharpie on the board to mark the negitive side before replacing any.
Start a thread on your progress.
wmclaughlin
New Member
It won't be for several weeks until I start on the sa 2001. I have 2 other projects in the pipeline. I want to complete those smaller less important recapps first. Currently recapping a Technics SA 200 for my son. I have another Broken Yamaha ebay special coming in but so these are some getting up to speed projects. I did work at Krell in Connecticut in the early 90's on the amp line so I'm not a complete newbie, but I worked on the manufacturing side this refurbishing is a new ball game for me. Thanks for the advice and insight.
wmclaughlin
New Member
So my Realistic SA-2001 integrated amplifier I have been using for several weeks kind of stress testing it and I came across a problem. It is now going intermittently into protection mode. I will be in protect for some time today I decided to put it on my bench and take a look. After poking around, and taking a few measurements, it started working and I was able to turn it on and off several times with the relay clicking in . After screwing the power supply board back in it again is in protection mode. The bias voltage at the emitter resistors is around 20-25 milli volts and the DC offset when the relay does click in it good 10-20 millivolts. Does anyone have any suggestions on where to start. My B+ and B- voltages are good at 40 Volts and I have 24 volts on 2 test points going off to the phono board. Voltages at the relay are near 0 when the relay does not click in. Can someone point me in the right direction? These intermittent problem are a pain. Thanks
Lavane
Lunatic Member
If it stops when you unsecure the power supply board and goes into protection and you screw it back down I would be looking for a short. Maybe a wire, or a blob of solder close to the edge of the board grounds out to the chassis when the board is screwed down? Really loom over the under side the board. It's been awhile since I've been inside my SA-2001, but if you can get a good look at the underside of the board with the bottom of the chassis removed, look for anything that could be causing a short to the chassis.
wmclaughlin
New Member
Thank you for your reply. I'm sorry that I gave the impression that reinstalling the board might be the cause of the issue. It happens intermittently whether the board is secured or not. It seems to just have something to do with the state of the capacitors and transistors on the PS/Protection board because it will sometimes click in and sometimes not. I really don't think it is a faulty relay. I might be found wrong on that. I have all new electrolytics caps and new transistors coming tomorrow. My plan is to remove them one by one and replace all of them. There are only half dozen cans and half dozen transistors on that board. I'll be labeling all of the parts as I remove them with their locations and I'll be marking the board with the orientation of the caps ass I remove them. I have a semiconductor testor to check the pinouts of the transistors as they are removed to make sure the replacements are the same before installing. Hopefully it all goes well, I want to fix the issue before I more forward with recapping the whole unit. Any suggestions or guidance are apprecaited.
Lavane
Lunatic Member
We're any of the original small electrolytic caps on the power supply bloated, or discolored on they're side! Two of mine were. There's a dropping resistor that can get pretty warm, and so can the voltage regulator. I bent the resistor away as far as I could from the new cap next to it and also added a small heating to the voltage regulator. I used 105° caps on the power supply board when I replaced them too.
It was probably a good idea at this point to replace the sand parts on the power supply board. Regulator, diodes, etc.
wmclaughlin
New Member
I recapped the power supply and the protection circuit and amp board, and the amp is back working properly again. Eventually I'll need to do the phono board and the preamp but that can wait for now because it is all working fine
Lavane
Lunatic Member
Thanks for the follow up. I may have to dig into mine deeper as well.