Luxman RX-102 Right Side Gone

[RG1969]

As I said in my "question to the moderator", I posted this problem in AudioKarma under the "Vintage Solid State" section, using the name Oldhippy69. If I'm being rude posting here on your site, delete my entry, I'll understand.

I bought the Luxman new back in the early eighties, hooked it up tp a pair of original large Advents, sounded great. For the longest time, I've had a small problem with the balance control. You would get a lot of static and cutout when you adjusted it. I was fairly sure it was just dust build up and just let it go. That is the only problem I ever had with the unit. D

Due to a divorce, after twenty five years, it ended up in storage for a couple of years. I setup a nice room for music and reading and setup the hardware. That is when I found I had no right channel (almost). If you put on a set of headphones, turn all gains to the max, balance to right side only you can just make out the song that's playing.
What have I done. I downloaded the service manual, I had four yrars of electronics in highschool...but.... that didn't help me understand the manual. I opened the case, blew it out, checked all componets for anything odd. After removing some PCB's and panels, I found eight fuses...all good....too bad. I used a multi meter on the fuses to be sure. Also, there are two lighted bars on the front display that increase to the right as volume is increased. Only the left channel lights and moves as you turn it up or down.

Sorry for the long story but I thought some background would help. I take very good care of my equipment, so general abuse is not the problem.

I'm a retired software analyst and have a small woodworking shop where I spend most my time. I'd like to fix the Luxman if I'm able, just need a little (or a lot) direction. Hope someone has an idea or two.

Thank You All

[charliemb]

I presume the Luxman is an integrated amp because it has a headphone jack and volume / balance knobs.

If the Luxman has two external jumpers that separate the preamp from the main power amplifier, usually in the back, unplug the jumpers and plug in a line-level source like a CD player on the power amplifier.

If both channels product sound normally, then the preamp is the problem.

If so, I'd start by replacing that scratchy POT.

If not, it's likely the main power amplifier and you'll have to have that repaired

[john65b]

I had one of these Luxmans in College - one of the 'Suckface' Luxman where the faceplate retracts into the unit exposing the volume, loudness, bass, treble, and balance knobs. Paired with a pair of B&W DM220i and a Technics CD player and it easily was the best stereo in the dorm...oh the memories...

My guess is buy a can of de-oxit, and spray out the balance pot, and all will be fine...

[RG1969]

charliemb, thanks for the reply, it is a receiver with 70 Watts RMS a side. I'm not sure I understand your idea, computers I get, stereo equipment isn't my strong suit (to say the least). But... in the back are RCA's for the regular aux, phono and tape in/out...but there are also a "pre out" and "main in", which I've never used nor know anything about. But I can find out if it will help. Also, regarding the balance control, I pulled the board that holds the controls and used contact cleaner on them all. It fixed the statis but not the right channel. What can I try to do next?

Hi john65b, ya, it really does sound good. Not overly powerful but a nice sweet sound. Thanks for the post.

[charliemb]

Okay, if you see Pre-out and Main-in, then that's exactly what I was talking about.

Plug a CD player (or other line source) to the Main-in RCA jacks. Play music through the CD player. Does the amp play music on both channels?

If it does, then there is nothing wrong with the power amplifier section. Meaning that the problem is with your preamp section.

If it does not properly play music, then the problem is with your power amplifer section.

Divide and conquer.

[RG1969]

I did as instructed, CD pluged into the Main in conectors. I tested the right side and did't get any sound at all. I then hooked the speaker to the left side, I got about five seconds of music followed by a pop and the music stop. At or around the same time I could smell a rubber or pastic odor, not real strong and no smoke, that I could see. Ipulled the plug at once and that's where I currently stand.

[RG1969]

I didn't check the fuses prior to the last message. There are two sets of fuses on the main board, on set blew, I'm sorry but I have not been able to tell which side is right and left channels, the other set of fuses are fine.

[AndrewT]

Question posted 3days ago !

Why, oh why do you keep it a secret?

[bear]

well, the easiest thing to do is to locate a local repair place and bring it to them to repair. In the city where I live area pop. ~350,000 there is one place that does a lot of repairs, including TVs, etc... of course they will charge you for the repair. So it might be less expensive to go out and buy a different (used) piece of gear.

Any of the repairs you would have to make will require some knowledge of how to read a schematic, and find those parts in the unit, remove and install new parts, AND the tools and test gear to back that up...

Truthfully, I think that unless all you did is to blow some fuses this time, and all you need to do to restore the other channel is spray some cleaner into the balance pot, then the repair is beyond your level...

Replace the fuses, test the side again - DO NOT use a CD player in direct unless you pick a CD that you know that you need to crank the volume way up to hear it normally... otherwise you will be playing the amp at what you can consider to be "full volume"... Otoh, something like a tuner or tape player that HAS a volume control on it, or even a CD player with a volume control on it, starting with a low volume is fine...

You should remove the cover and look at the boards and see if there are any parts that are charred or discolored or if the PC boards show any discoloration.

Suggest posting a jpeg of the unit - the insides with the top off too assuming you have a digital camera. Use the lowest resolution setting, or have a way to knock down the res like photoshop...
and a scan of the schematic from your service manual, I think you said you had one.

But, again, unless the repair is going to be simple you will need to locate a local person or professional who can handle it. Perhaps if you say where you are, people may be able to suggest someone?

I think everyone has had the same experience you are now having, but some of us went through this some time ago...

_-_-bear

[charliemb]

Wish you would have checked the fuses before you posted even for the first time. :-)

Anyway, the fact that no music played when you plugged in a CD player proves that the scratchy POT in the preamp was leading you in the wrong direction.

The problem is at least with the main amp. If you are lucky, all you have to do is replace the one burned fuse and all is well except for the scratchy POT. Let's hope that the pop and the rubber smell was nothing more than a thermal protection circuit going off to protect the unit. Possible. (fingers crossed)

I agree with Bear that if the fuse does not fix it, you may have to go to a repair shop and get it fixed, or buy a piece of good used gear for cheap.