Luxman R-115 vs R-117 and R117 recap project.

Almost there....

Things are fairly easy to reach but requires a fair bit of disassembly and did take about 5-6 hours so far over the past week. I’m a novice and triple checked polarity, values and type for every capacitor and did it 45 Minutes to an hour at a time. Also took the time to pre sort the capacitors by board.

In progress...

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Face looks to be aluminum with plastic buttons. Knobs might be metal. Had to remove this and a fair number of other parts to get to the tiny caps on the tone control board.

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All but tuner section board, 120volt 10,000uf, and display board recapped and ready for reassembly. Lots of little wires to connect and bundle. Thankfully these are documented in the service manual since I didn't take pictures or notes.

Cleaned up mica insulators can be seen on the heat sink ready to be dabbed with the aforementioned heat transfer compound.

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Will tackle that tomorrow evening and hopefully get to compare if everything was done properly. Fingers crossed!



Sam
 
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Took me about four hours to re-wire and reassemble everything but I took my time. All that’s left is to replace the zip ties and holdbacks for cable management and then hopefully everything works.

If all is good, I’ll swap out the relays and start the listening comparison.

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Thanks jheu2 and Yukon888.

I got this... but see no data sheet or if it’s been ‘supplemented’ with metal powder (htso2s Silicone compound).

http://d.digikey.com/qXKS070yNf0p2zS0X0mv00y
Both Toshiba and SanKen recommend these thermal compounds; (The following provided by Toshiba) HTC is certainly a recommended choice, and Wakefield 120 is also a good choice.

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HTC is loaded non-silicone grease with zinc oxide.

https://www.electrolube.com/pdf/tds/044/HTC.pdf
 
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So finally got around to the 1st fireup after recapping and the results were spectacular. Unfortunately, the wrong kind of spectacular involving the loss of magic smoke.

Hooked up a set of speakers and the CD player. When I turned the volume up, heard a loud pop and a wisp of white smoke that disappeared as fast as it appeared. Had the cover off so could see that it came from the area between the speaker terminal board or perhaps the main amp board inboard of that. Shut everything down and waited a few mins to think about it and then started the unit back up. No smoke and both LEDs are lit on the amp boards. Sound coming from the CD player is extremely scratchy. Super scratchy and fairly low volume whether cd direct is pressed or not. Tone controls seem to be working. Sound appears to be coming out of both speakers, but stronger on the right and distorted and low on both channels and balance control appears to be functioning. I'd describe the sound like an analog tuner where the frequency is off 1/3 of a mhz.

Any suggestions on what to look for or how to best begin the troubleshooting process? Any particular measurements to take?

My immediate thoughts are to visually inspect and look for something burnt or blown up as a first step and perhaps gently prod around the wires and boards with a wooden rod to see if any loose connections make themselves evident.
 
So finally got around to the 1st fireup after recapping and the results were spectacular. Unfortunately, the wrong kind of spectacular involving the loss of magic smoke.

Hooked up a set of speakers and the CD player. When I turned the volume up, heard a loud pop and a wisp of white smoke that disappeared as fast as it appeared. Had the cover off so could see that it came from the area between the speaker terminal board or perhaps the main amp board inboard of that. Shut everything down and waited a few mins to think about it and then started the unit back up. No smoke and both LEDs are lit on the amp boards. Sound coming from the CD player is extremely scratchy. Super scratchy and fairly low volume whether cd direct is pressed or not. Tone controls seem to be working. Sound appears to be coming out of both speakers, but stronger on the right and distorted and low on both channels and balance control appears to be functioning. I'd describe the sound like an analog tuner where the frequency is off 1/3 of a mhz.

Any suggestions on what to look for or how to best begin the troubleshooting process? Any particular measurements to take?

My immediate thoughts are to visually inspect and look for something burnt or blown up as a first step and perhaps gently prod around the wires and boards with a wooden rod to see if any loose connections make themselves evident.

There's probably a leaking transistor somewhere. I'm surprised the unit as audio at all. It's definitely an amp issue. Look for shorts, check the transistors, see what's up.
 
follow up... Good news, bad news!

Bad news, is I'm a dummy and and the cd player was hooked up to phono. Hope I didn't damage anything there, but relieved it's sounding good, but I'll hold off on the comparisons until I get this escaping smoke licked.

I think I found the culprit...

Here's the capacitors on the power supply board that appears to have spilled their guts. (brown elna just above the transistor? on the heatsink and the one next to the 3 blue nichicons seems to be really puffy on top also)

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What might have caused these guys to pop? I'm assuming there's something I'll need to figure out before just replacing the blown bits.
 
Thanks for the quick reply! Your ak handle has me in stitches, I can't bring myself to type it, lol.

I'm thinking that since I'm seeing blown caps I should be double checking the capacitor values and tracking backwards toward the transformer from the blown caps, checking voltage along the way?

Since I'm 'doomed' to remove the power supply board, I'll post which capacitors. I do see in the service manual a table of voltages for "E, C and B" for the transistors, so perhaps once I determine where in the circuit the blown caps are, I can see which transistors to check.
 
I'm sure you checked already but first thing I would check is that I had the caps in correctly (polarity). Sorry, but I'm afraid I can't offer much help with this problem.
 
Thanks Yukon, I was thinking the same thing on the polarity as well as the voltages/values, as there's several different voltages for the caps on that board.

No worries as I'm (perhaps naively!) hoping that since the damage is early in the circuit it shouldn't be as complex an issue to figure out.

Going to unplug it, let it cool off, have a beer, maybe pull the board, and start with fresh eyes after work tomorrow.

Edit.. Upon closer inspection, it appears that only one cap is blown. (one above transistor) and that was indeed installed in the wrong polarity, as compared to the photos in the other threads. Hopefully, that's the only one I flubbed and I hopefully have a spare nearby, but can put the original cap back in a pinch until the new one comes.

Wish me luck that it's that simple!
 
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Ok, so the somehow beer gave me energy and new perspective and so more good news / bad news.

Good news: Had mistakenly ordered a few extra caps and a 25v 47ohm Elna replaced the blown item. Was getting left sound only, but traced this to the right amp board mounting point. Connector pin must have backed out a bit and after some fiddlin' with the connector, we've got nice clean 2 channel sound. Tone controls and loudness work. Tone defeat is a bit crackly but doesn't make a difference in or out and subsonic button seems to be working fine also.

Bad news: Only get sound in CD direct mode. Can faintly hear the cd player if not in cd direct mode.

Silver lining: What I'm hearing out of the speakers sounds simply amazing! Incredibly fat sound and bass response is way lusher and tighter than before. Might let this run overnight to 'break in' the caps, if that's such a thing and hopefully the fix is near.
 
Decided to deox the signal processor switch after reading a few AK threads and it seems we've now got a fully functioning receiver, almost. This explains the faint signal, I think.

The display was not on, but prodding the cable going to it from the power supply board lit it back up, so another connector issue it appears. (did I say this thing had a ton of wires? There are 23 sets of cables, some of which are 11 pins coming in/out of the CPU board alone.)

Once I get this last thing licked, I can finally put this sucker back together and it seems we're on a path to a critical listening evening tomorrow night.

Thanks all for the suggestions and help!
 
Check the solder joints on all of the connectors if you already have everything disassembled. You might as well.

Thanks for the tip and will do. While I didn't have to take it apart as the incorrectly positioned cap was reachable, I can see the boards where the connectors are fairly well as I still have the bottom off and most all connections are along the top and bottom edges of the boards. Went ahead and reflowed the connector that was buggy for the right channel, just in case.

Been listening for the past few hours and think I've got a stable receiver. Initial impressions are as follows:

1. Difference between cd direct on and off is smaller. Both got better but the 'preamp included' setting got much closer to cd direct. Almost imperceptible, and a very slightly different sound signature.

2. Clearer and more bass authority are the most immediately noticeable improvements.

3. This receiver made my speakers disappear into nothing better than the 115 that I can remember from memory, so looking forward to the A/B comparisons.

4. There was an edginess at first that seems to be smoothing out. I've heard that capacitors breaking in is a myth, but I can absolutely say that things are getting smoother as it plays on. My own experience recapping 3 other amps/receivers has been the same so I may either be crazy or crazy :)
 
Hope you get it working and it's something simple.
''

thanks lico, display problem turned out to be the pin connectors on the power supply side losing their 'grip' likely after being spread from my repeated removal/reconnection getting the wires routed in the most organized ways.

******edit --- this actually turned out to be the pins for the connector on the power supply board needing to be reflowed. The problem came back and the tightening of the connector pin receptacles must have put a little extra pressure on the loose pin, allowing it work for a bit, until I pulled the wire again to replace the zip ties. Kudos to Porkbuns for suggesting this to check the solder joints*****

If this works flawlessly over the next 24 hours, I think I'm in good shape.
 
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Gaaaaaaaawd daaaaaamm! This thing sounds good. Really surprised, and don't think it's going to be a contest but I did have 2 whole beers, lol. Listening to Bob Dylan, Norah Jones, Mark Knopfler on CD and Nirvana (nevermind reissue) on LP so far.
 
Looks like we have a stable, fully working receiver now. Any suggestions on what else to do before buttoning her up and getting onto the comparison?

Check/adjust bias? Anything else?
 
Congrats on the success so far. Definitely check bias (idling adjustment - page 5 in service manual). If you don't already have mini hook leads, or alligator clip leads for your meter, I highly recommend them to attach to the test points for this procedure, along with an insulated trimmer adjustment tool. Also, be aware that a very small turn of the trimmers will make a big change in value.
 
Thanks again Yukon888,

I do have the mini hook leads and a set of 'tuner sticks' that are either all plastic or plastic handled. Should I aim for the 5mv in the service manual or as low as possible but still positive? (i.e. say 2mv, if I can?)
 
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