Monday, May 21, 2012

Tricks used in removing smell from Marantz 2130

Marantz 2130 reinstalled in Kitchen, now unlit dial
I finished the smell removal process and re-assembled my Marantz 2130 on Saturday night.  By 1am or so I had it set up again in the kitchen, and I played with it until 5am or so, listening to the usual 3 stations plus scanning the dial.  It really is fun to have an analog tuner with scope at one's fingertips, and I think this sounds better than a Kenwood KT-8300.  Which reminds me how way back in the early 1970's people would make fun of the TOTL Marantz tuners as being "Pioneer with a scope."  Well it wouldn't be far into the 1970's when "Pioneer with a scope" would more praise than put down.  Pioneer was known for making good sounding tuners, arguably the best sounding!  The 2130 does in fact sound a bit "Pioneer" to me, not unlike a Pioneer 9500 mkII.  Very dynamic, punchy, musical, open, but also quiet.
Cleaning inside the tuner with Q-tips and Alcohol
Probably the #1 trick in making the smell go away was removing the dial lights.  I was originally going to return the dial light circuit board after cleaning it, but then I noticed I had already cleaned the top pretty well, and the bottom was essentially clean.  So then I wondered, why did it make so much difference to the smell having the dial lights removed vs connected?  Well of course the dial lights generate a lot of heat, looks like 15W or so, nearly half the power consumed by the entire tuner.  That heat drives a lot of ventilation airflow through the tuner, ultimately ejecting hot air at the front edge of the top cover.  Plus, the interior of the tuner is directly heated by IR emissions from the dial light assembly, and gets much warmer.  So the dial lights are driving a process of vaporizing crud inside the tuner and conveying it to the outside, a worst-possible scenario for smell.

I'm guessing that 50-80% of the total progress I made in smell elimination (reduction, actually, but nearly elimination) was from removing the dial lights.  I'm not particularly bothered by the unlit dial, which can be easily read under room illumination.  Eventually, I'll devise a string of LED's for the dial light.  They won't get hot and won't cause the outgassing of smelly stuff.  Funny about the time this tuner was made other manufacturers went to unlit dials.  Famous tuners with unlit dials include the Pioneer F-26 and Yamaha CT-7000.

I'm suspicious that the Marantz repair center replaced all the dial bulbs with new standard replacement bulbs, but the 2130 possibly requires lower wattage bulbs.  I'm just guessing, I felt the dial was brighter than it should have been, but it didn't look washed out either.  The brighter dial was driving more release of smell.  The dial is mostly metal, only the numbers and indicator marks light up through hairline openings in the dial metal covered with blue plastic.  Seems like a waste that so little light should be produced outside when so much light was being created inside.

Now even after running the tuner for 18 hours at one time, I smell nothing right next to it, UNLESS I sniff right where the dial needle indicator light (still connected), jewel indicator lights (for FM and Wide Band), and Stereo light.  There, I can still smell a slight bit of the original smell.  I'm thinking I could make further progress by disconnecting those lights or converting them to LED's also.  Why should a light light up to show you have selected FM?  I've usually selected FM, the separate light for indicating AM is sufficient to know if I haven't.  For Wide Band, it would make more sense to have the light glow for narrow band, to remind me to turn it back to wide band.  In general, lights should indicate things you might want to change, temporary and possibly undesireable warnings rather than permanent situations.  That way, as an additional benefit, they can be off mostly.  My final idea along these lines: change the Stereo light to an "unStereo" light which only lights up when the stereo carrier is too weak to get stereo, or if you have mono selected.  Perhaps a special light for mono selection, once again to remind you to turn it off.  No lites on should mean optimal reception, nothing to think about.

Other things I did:

1) Washed top and bottom covers and faceplate and screws in soapy water and alcohol.  Placed outdoors on sunlit table in afternoon several times.

2) Put chassis on outdoor sunlit table on breezy day.  Turned upside, downside, front, and back.

3) Cleaned off chassis metal with cloths damped with water and Everclear.

4) Cleaned off chassis metal, plastic dial assembly, transformers, backside of two circuit boards facing up, gyro-touch knob and protective plates, and edges and corners of IF and other circuit boards with magic solvent.

"Magic solvent" is Everclear (95% ethanol) with with 1 drop per ounce Thieves' Oil (natural fragrant antifungal) and 1 drop per ounce DeOxit.  I'm not sure if the DeOxit does much good in this formula, it didn't intermingle.  The Thieve's oil is sufficiently light that you can't much smell it much directly, but it seems to cancel out the bad smell, and I think the bad smell may be partly fungal...a fungus eating on the cigarette smoke residue.  Anyway, the smell of Thieve's Oil is very pleasant, so it wouldn't bother me if I could smell it.

5) Removed dial light circuit board, clipping green wires that powered it, bending them so they won't contact anything.

6) Re-washed cover with magic solvent.

As an additional repair, I also put two wire ties from the retaining clip on the front end assembly cover, threaded through slots in the dial assembly.  This holds the wire for the needle indicator light, preventing it from falling on the IF circuit board.  I have previously used only one wire tire, switching to two wire ties seemed to make it a bit better, though still the wire can fall during certain tuning operations to be only 3/4 inch from the board (when I first got the tuner it would drag across the board while tuning), on average, it's mostly suspended by wire ties at the maximum height.

When I cleaned with simple water, I didn't see much coming off.  But q-tips dipped in the magic solvent would quickly get brown cleaning off chassis metal or the corners of circuit boards.  I used up about 100 Q tips.  The underside of the tuner did not get cleaned with magic solution, though I did use water and everclear on cloths on chassis metal.

Success!  The smell is barely detectable, even close up to the tuner after many hours of operation (and I think that's mostly because of the 4 still operating lamps).  And it still works, putting the cover back on has restored normal operation compared with the way it was 3 weeks ago when I first took the cover off.

The tuner runs much cooler without the dial lamps (as shown in picture at top).  The faceplate is ice cold, the cover merely only just noticeably warmer than not after 18 hours of operation.  I think I could put a Marantz wood case on the tuner now.  Previously I worried that a wood case would trap too much heat.  I have a Marantz wood case which might fit.

1 comment:

  1. Hello Audio Investigator! This article seems to have solved a noxious odor problem that had shelved my 2275 for years. I clipped the green wires that powered the dial lights and the odor is gone! Thank you!! Have you been able to locate LEDs that would be an adequate replacement for the original dial lamps? No power to the dial board leaves me with no way to see the tuning dial at all - still preferable to the smell, but it would be nice to get light where there is non now. Thanks again!