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In Reply to: RE: I've got one..... posted by Rod M on September 21, 2010 at 17:15:28
Hi, Rod:
Thanks very much for posting and the image of your black anodized 10-B.
Is the lettering created below the surface of the panel, which to my knowledge, was achieved by a process called "photo-etching"?
Judging on the basis of your image, I would caution you to not attempt cleaning both of the glass front glass panes. I have heard way too many cases whereby the lettering crumbled or was damaged in cleaning these with normal products such as Windex. The right end of the glass seems to show some discoloration from the rubber block support behind it. Just leave things as they are!
Any problems to report about spontaneous loss of detection?
All three of my 10-B's do this once in a while.
Thanks again!
Richard Links
Berkeley, CA
Follow Ups:
We cleaned out part of the basement where most of the gear boxes were stored. It was more of a shuffle to other places where there's a crawl space, actually 5 to 3 feet, so not on your knees exactly.
My son quickly latched onto the now nearly empty bedroom in the basement since the heat wave hit.
Anyway, the black faceplate is definitely etched with white lettering. I can't tell any difference from a silver one other than being black.
-Rod
Hi, Rod!
Nice to hear that you located your baby!
It does look pretty impressive, afterall!
Richard Links
Berkeley, CA
You know, it's been a while since I've seen it. When I bought it, I'd just gotten the silver one and it had been aligned and had a few caps replaced. I just bought the black one because I'd never seen one. I used it for a while and it seemed to be in good shape, but then I also have a McIntosh MR78 which while not sounding as smooth did a better job of picking up weak stations, so I was using it.
I just hooked up the silver one in the new house when we moved and the black one is in a box buried with 50 others in the basement.
Anyway, I seem to think the lettering is etched, but I wouldn't swear to it. I'm needing to rearrange that stack, so I'll check it if I run across it.
I've never had loss of detection with the silver one. The black one wasn't run all that long though I seem to recall that it might have had a bit of the opto-coupler problem.
Thanks for the tip on the glass. I've heard that before and the black one is dirty, looks like smoke residue as well. I thought about getting the replacement one from Classic Audio. And someone did clean the silver one probably as a piece of the 10B logo is missing along with part of a number on the FM. You have to look to find them, but it's a bummer.
Oh well, for being nearly as old as I am, it's in better shape.
-Rod
Hi Rad, thanks for your answers and picture.
How does an optocoupler problems appeares, how can one detect it?
Maybe a little bit off-topic, but how can i test a 10B for the most common problems? What should i check when i test it without any electric equipment, just in normal modus in my system? I have some other good tuners, so of course i can compare sound and signal strength on special stations.
But any other special things i should be care of?
Hi, Rob and others:
I had this very elaborate response ready to post and just lost the whole darn thing!
Below is a resource you should carefully examine. It represents the most complete assembly of such information that I know of or have come across and it has fairly recently been made available to us for FREE on the web. THANKS TO WHOMEVER for DOING THAT!
:-)
If your opto-couplers fail, you will see a straight vertical line or a straight horizontal line on your display. A diagonal line in the stereo mode would tend to indicate either a weak signal being switched to mono or failure of the circuitry responsible for proper switching. There are bulletins about this on the site I mentioned.
In addition, there are a few little suggestions also included on this site which are very helpful to any 10-B owner. Testing and or swapping tubes may restore proper operation to the tuner. I once helped a local owner who called and told me that he could only receive signals in the upper portion of the FM spectrum. We tested tubes and discovered a weak 6DL4 in the front end and when it was replaced, this restored proper operation to his tuner.
Basically speaking, the opto-couplers contain either a single neon lamp and a pair of cadmium disulfide photo cells (CDS cells) or in the cae of the module controlling muting function, that module has inside of it only a single lamp and a single CDS cell.
You can remove them and slice them open with a jeweler's saw. Inside you will find a wafer of styrofoam with the aforementioned parts mounted through it. The whole affair is shielded from any stray light with a collar of black light-absorbant material.
I believe the aside from failure of the opto-couplers, the only other trouble involves what we call "spontaneous loss of detection". And, I jokingly say that only the guys in GhostBusters can help us all in that regard!
I have made my own replacements for the opto-couplers from parts found right off the shelf of RadioShack in the past. I do not know the exact specification for matching the CDS cells, however and have never actually seen it published.
Lastly, to my knowledge, only L&M Electronics in San Francisco, ever offered an upgrade modification for the failing optocoupler units. The owner, a fellow who goes by the name "Wally" (for Wolfgang) designed a small circuit board on the basis of some integrated chips which took the place of these funky old neon-lamp / CDS devices. In the early eighties, it would cost you $150 for that mod, and if he still offers to do this, you can only guess what it might cost you!
There are after-market home-brew replacements for the opto-couplers often made available via eBay. They are about $125 or so for three units, I believe.
I have no experience in using them nor do I have any opinion on them or the person offering them for sale.
But they are there if you need them!
Good Luck!
Richard Links
Berkeley, CA
...an exploded view of a 10B dual cell optocoupler.
Hi, Steve:
Certainly do recall that nice image!
In fact, I have put a copy under my pillow at night for the sake of tuner safety.
:-)
Richard Links
Berkeley, CA
Marantzguy could surely expain this better, but the problem is that these wear out causing the unit to randomly flip from stereo to mono mode.
-Rod
Hi, Rod:
From your response, am I to understand that you own 50 Marantz 10-B tuners?
Yikes.
Turn them all on and brown-out your area!
Richard Links
Berkeley, CA
The other 49 boxes are several other tuners, receivers, speakers, phono preamps, reel to reel tapes and other junk*.
* Junk, according to my wife.
-Rod
Hi, Rod:
That is a little more like it!
Well, let me tell you that in the mid seventies, when I was looking to buy my second Marantz 8-B power amp, I answered an ad in the newspaper where one was advertised for sale. At that time, the going price was generally around $225. When I got to the home of the guy who placed the ad, I found that the entire flat was crammed full of unbelievable audio gear.
After my purchase, the seller took me around and after passing one entire room filled to the top with loudspeakers of all descriptions, he showed me the contents of one closet. Inside were four factory sealed cartons each of which contained a Marantz 10-B. He was asking $1K each for these tuners at a time when they also went for perhaps $500 in tip-top condition.
I never got over seeing all of that stuff and believe me, there was an entire wall of McIntosh gear as well, but not in sealed cartons!
Incidentally, the seller was a guy named Harry Stephens and he had to weigh at least 300 lbs. I doubt if he is still around these days, or maybe he was put to rest with all of his gear.
:-)
Richard Links
Berkeley, CA
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