Bastian
New Member
Hello Everyone.
I am more of a DYI, hobbyist, but very much after the music rather than a proper technician. However, I have in the past effectively recapped couple old units for the sake of it, changed resistors to fix hiss, and never faced significant issues.
Now, to the point. I have a Yamaha M-45, which happens to be my favourite current unit. Might be synergy with other components? I don't know. Anyways! I decided to take preventive measures as it is getting old and, well, went in for a recap during some days off I had, cleaning volume pots, etc. Got a pair of 22000 uf / 80 V Nichicon KG to replace the big caps from Mouser, Canada. I took the old ones out while looking at the soldering side of board carefully taking the tin out.
To my surprise when I looked at the other side of the amplifier there were no signals for what should be the positive or the negative for these big caps. I said, No problem! and went to look into the pictures I always take to review anything. Now, the sets were different and the pixels were downsized on the camera, unreadable pictures in other words. I then went to read schematics and check the thing, I thought had it all figured out, turned up the amp and blew the fuse instantaneously. Honestly, I checked everything. Nothing else could have gone wrong (as if this is not already a major issue) but the polarity of these caps. Can anyone offer a hand? (By the way, I have used Wire soldered to the flat leads of the Nichicons. Then I sent the wire through the holes and soldered to the board eyelets in a substantial way. The weight of the main filter caps is being supported by the plastic bracing that comes with the amp. )
Let's start with this... how should the main filter capacitors be placed then? On the schematics, they come as C172 and C171. However, on the circuit map, they would not show. Looking at the front of the unit, I assumed C172 would be the right Cap, as the + side shows connected directly to Q147 and Q148. So the final positioning would be right cap (C172) positive towards me, and negative towards the back of the unit. Left cap (C171) would be Negative towards me, and positive towards the back of the Unit. This looks like is probably very wrong. A little help here will be amazing. That... if turning the main caps to where they should be and replacing the fuse would bring the amp back and I did not kill it altogether.
Another thing... should I plug speakers to turn the unit on for this kind of amplifier? I did have nothing plugged to it. Might that be it? I will follow advise and if this does not work, I will advise back and we will go from there.
Thank you for the help to everyone beforehand!
I am more of a DYI, hobbyist, but very much after the music rather than a proper technician. However, I have in the past effectively recapped couple old units for the sake of it, changed resistors to fix hiss, and never faced significant issues.
Now, to the point. I have a Yamaha M-45, which happens to be my favourite current unit. Might be synergy with other components? I don't know. Anyways! I decided to take preventive measures as it is getting old and, well, went in for a recap during some days off I had, cleaning volume pots, etc. Got a pair of 22000 uf / 80 V Nichicon KG to replace the big caps from Mouser, Canada. I took the old ones out while looking at the soldering side of board carefully taking the tin out.
To my surprise when I looked at the other side of the amplifier there were no signals for what should be the positive or the negative for these big caps. I said, No problem! and went to look into the pictures I always take to review anything. Now, the sets were different and the pixels were downsized on the camera, unreadable pictures in other words. I then went to read schematics and check the thing, I thought had it all figured out, turned up the amp and blew the fuse instantaneously. Honestly, I checked everything. Nothing else could have gone wrong (as if this is not already a major issue) but the polarity of these caps. Can anyone offer a hand? (By the way, I have used Wire soldered to the flat leads of the Nichicons. Then I sent the wire through the holes and soldered to the board eyelets in a substantial way. The weight of the main filter caps is being supported by the plastic bracing that comes with the amp. )
Let's start with this... how should the main filter capacitors be placed then? On the schematics, they come as C172 and C171. However, on the circuit map, they would not show. Looking at the front of the unit, I assumed C172 would be the right Cap, as the + side shows connected directly to Q147 and Q148. So the final positioning would be right cap (C172) positive towards me, and negative towards the back of the unit. Left cap (C171) would be Negative towards me, and positive towards the back of the Unit. This looks like is probably very wrong. A little help here will be amazing. That... if turning the main caps to where they should be and replacing the fuse would bring the amp back and I did not kill it altogether.
Another thing... should I plug speakers to turn the unit on for this kind of amplifier? I did have nothing plugged to it. Might that be it? I will follow advise and if this does not work, I will advise back and we will go from there.
Thank you for the help to everyone beforehand!
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