My mother recently blew the right channel of her 6.1 Marantz home theater receiver last month and I have dismantled it and am ready for diagnosis and repair. I will post pictures in my next post. I am wondering if anyone can tell me where on the mainborad I should start my diagnosis. Experience tells me to start with the transistors by measuring for any inconsistencies and then to do the same with the main capacitors (huge 1000 mfd caps). She blew the right channel by letting the + and - wires touch at high volume and now all that comes through the speaker is a faint hint of sound (almost like playing a blown speaker). I would be every so grateful if someone could offer me any advice on the matter. I have a multimeter that I am somewhat familiar with but could use a little help as is apparent. Thanks in advance.
Is there still a warranty left on the thing?
But wait, that would not be the DIY thing to do would it 😉
But wait, that would not be the DIY thing to do would it 😉
Here is a bird's eye of the main board, I have circled the sections I would focus in on. Anyone have any direction for me to go on this? I will post another picture of the transistors on one of the channels. I want to test the two huge capacitors to make sure they are both good. How do I test capacitance?
I think you are looking in the wrong places. If it's a 6 channel amp there should be 3 output module/chips at the very least (assuming 2 channels per chip). 6 pairs of transistors if modules/chips are not used. Where is the main heatsink? And what is attached to it?
IMO it's pointless looking at the PSU caps - if there was a problem with them it would affect all channels.
IMO it's pointless looking at the PSU caps - if there was a problem with them it would affect all channels.
I believe this is what you may be talking about. There are six sections respective of the six channels and a huge heatsink for all six channels (as per your description). How can I tell which section is the right channel? Which components should I test when I find the right channel (resistors, diodes, caps, etc)? I don't know if this helps in diagnosing but sound still comes through the right channel it's just that it is muted almost to nothing and sporadic on the sound it lets through.
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Can you trace from the output terminals for the blown channel back to where it connects to that board mounted on the main heatsink?
I suspect just-functioning output transistors. You can diode test them in situ, but I wouldn't bother as they will probably read OK. If you really want to check them, measure all the other ones as well and compare readings. You may have a tough job hunting down exact replacements... They will probably be 2SCxxxx and/or 2SAxxxx devices.
I suspect just-functioning output transistors. You can diode test them in situ, but I wouldn't bother as they will probably read OK. If you really want to check them, measure all the other ones as well and compare readings. You may have a tough job hunting down exact replacements... They will probably be 2SCxxxx and/or 2SAxxxx devices.
EUREKA!!!
Culprit found!!! Low and behold I was digging in the wrong place (as I suspected). I put the receiver back together discouraged and ready to take it in for repair tomorrow but decided to check one last thing. I removed the transistor board and unhinged the heatsink to find two massive 5 pronged output transistors fried to oblivion. I tested resistance and got nothing on one and on the other some really crazy readings. I suspect (hope as well) replacing both of these transistors will solve the problem. That would be nice. One is labled SK SAP16 NY 1330 and the other SK SAP16 PY 1327. Each channel on the amp is set up this way. Does anyone know where I might find these transistors and how much they would cost?
Culprit found!!! Low and behold I was digging in the wrong place (as I suspected). I put the receiver back together discouraged and ready to take it in for repair tomorrow but decided to check one last thing. I removed the transistor board and unhinged the heatsink to find two massive 5 pronged output transistors fried to oblivion. I tested resistance and got nothing on one and on the other some really crazy readings. I suspect (hope as well) replacing both of these transistors will solve the problem. That would be nice. One is labled SK SAP16 NY 1330 and the other SK SAP16 PY 1327. Each channel on the amp is set up this way. Does anyone know where I might find these transistors and how much they would cost?
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Man that looks ugly. Too bad a commercial design of modern date can't
handle some hot-plugging.
The transistors have integrated emitter resistors so at least you don't
have to worry about thoose (unless they added extra externally).
Change the transistors and pray to god the presceeding stages are OK.
/ Good luck / Mattias
handle some hot-plugging.
The transistors have integrated emitter resistors so at least you don't
have to worry about thoose (unless they added extra externally).
Change the transistors and pray to god the presceeding stages are OK.
/ Good luck / Mattias
Thank you everyone for your posts on this. I have ordered parts from Profusion. They only accept orders on quantities of 5 on each part so I will have some surplus for sure in case Mom blows another channel or somone here sees this post and needs the same parts. Much cheaper than Marantz, that's for sure. They wanted $42 a pop for a total of $84 plus $7 shipping. Profusion only wanted $4.31 a piece. Do the math. Even at quantities of 5 I am saving a substantial amount of money and I have the pleasure of ordering from my ancestors in the UK.
SUCCESS!!!!!!!!!!
SUCCESS!!!!!!!!!! The parts arrived...12:am just finished installing them. Power on...success!!! The right channel is fully restored, all systems go. Thanks everyone for helping. I was a bit skeptical in my ability.
SUCCESS!!!!!!!!!! The parts arrived...12:am just finished installing them. Power on...success!!! The right channel is fully restored, all systems go. Thanks everyone for helping. I was a bit skeptical in my ability.
Did I speak too soon???
I think I may have spoken too soon. When I tested the amp with FM radio reception a problem was masked...static. When I got the receiver to my Mother's and hooked it all up I was discouraged to hear some static noise coming through the right channel. It is not loud but it is there and you can only hear it at low volumes. Also, when my mom folded a blanket that was four feet away from the receiver the static got really loud and pronounced but then died down once she was finished folding the blanket and conducting static electricity. Wow! That is weird. So...back to the drawing board as they say. Any hints at what could be causing this static or feedback? Thank.s
I think I may have spoken too soon. When I tested the amp with FM radio reception a problem was masked...static. When I got the receiver to my Mother's and hooked it all up I was discouraged to hear some static noise coming through the right channel. It is not loud but it is there and you can only hear it at low volumes. Also, when my mom folded a blanket that was four feet away from the receiver the static got really loud and pronounced but then died down once she was finished folding the blanket and conducting static electricity. Wow! That is weird. So...back to the drawing board as they say. Any hints at what could be causing this static or feedback? Thank.s
Dunno but from the attached pictures you did take everything apart.
Maybe there is some loose connection, mechanical (screw) / electrical (connector).
Sometimes theese boards have some screws that both fixes the boards
and also serves as grounding to the shassis or cooler.
Try to touch the speaker terminals, shassis etc and listen.
Also check that all your input cabling is properly connected.
Or maybe it was there before and you noticed it know since your ears
got more critical to evaluate the repair.
Long shoot: try reverse the ac plug in the wall socket.
Keep us informed / Mattias
Maybe there is some loose connection, mechanical (screw) / electrical (connector).
Sometimes theese boards have some screws that both fixes the boards
and also serves as grounding to the shassis or cooler.
Try to touch the speaker terminals, shassis etc and listen.
Also check that all your input cabling is properly connected.
Or maybe it was there before and you noticed it know since your ears
got more critical to evaluate the repair.
Long shoot: try reverse the ac plug in the wall socket.
Keep us informed / Mattias
Check the chassis is correctly grounded. particularly make sure there is no short between the chassis and any of the signal grounds as this will probably inject noise into the preamp stage.
Does the reciever take power with ground ?
Does the reciever take power with ground ?
Problem resolved, we're back in business!
The feedback I was getting through the right channel was either due to defective part(s) or poor solder joints. I went in and replaced both of the new transistors with two new ones (I ordered 5 of each so I had some extra). I resoldered them back in making sure the solder joints were very high quality. My soldering has improved immensely from this project alone. I must say I did a very fine job. Another possible culprit was a copper lead that burned off of the board when the original transistors went up in smoke--it was no longer making contact with the leg of the transistor and I think I did a very poor job of resoldering it the first time. I worked from 12am to 2:30am very meticulously to get it right and the end result was worth all the effort and hard work, not to mention midnight oil. I hooked the receiver up with a healthy dose of skepticism but to my surprise the right channel was fully restored and produced absolutely zero feedback. I thoroughly tested it this time correctly and got the same results every time. With that I put it back together and cleaned up my mess to keep the better half pleasant on a Saturday morning. I returned to my mothers and hooked everything up without a single problem or hint of mistake. Brings great satisfaction to fix something like this the amount of money saved. Everyone on this post has been a great help--this truly is an invaluable resource. Thank you all once again. I should hope this is my last post (fingers crossed), I think I really fixed it for good this time. Thanks again.
The feedback I was getting through the right channel was either due to defective part(s) or poor solder joints. I went in and replaced both of the new transistors with two new ones (I ordered 5 of each so I had some extra). I resoldered them back in making sure the solder joints were very high quality. My soldering has improved immensely from this project alone. I must say I did a very fine job. Another possible culprit was a copper lead that burned off of the board when the original transistors went up in smoke--it was no longer making contact with the leg of the transistor and I think I did a very poor job of resoldering it the first time. I worked from 12am to 2:30am very meticulously to get it right and the end result was worth all the effort and hard work, not to mention midnight oil. I hooked the receiver up with a healthy dose of skepticism but to my surprise the right channel was fully restored and produced absolutely zero feedback. I thoroughly tested it this time correctly and got the same results every time. With that I put it back together and cleaned up my mess to keep the better half pleasant on a Saturday morning. I returned to my mothers and hooked everything up without a single problem or hint of mistake. Brings great satisfaction to fix something like this the amount of money saved. Everyone on this post has been a great help--this truly is an invaluable resource. Thank you all once again. I should hope this is my last post (fingers crossed), I think I really fixed it for good this time. Thanks again.
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