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PostPosted: Sat Sep 09, 2017 10:18 am 
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Joined: Mon Aug 08, 2016 5:46 pm
Posts: 300
Location: Markham, ON, CA
Hi folks. I have a bit of a challenge with my (new to me) Sansui TU 999. When I try to change station, the tuner knob spins and does not move the "string" to actuate the tuning. If I remove the cover and move the tuner wheel directly, the knob spins , the channels are accessed, all works well. The interior of the tuner is a little bit dusty and has (obviously) not been serviced in a while. With that said, the tuner is really sensitive, "locks" on stations with no drift and sounds almost tube-like (that is good)....I am really pleased with everything except there is limited ability to change stations without leaving the cover off.

I have (carefully) used deoxit gold to clean out the old lubricant and dust. The tuning wheels are moving better already. Is there such a thing as some sort of rosin (sp?) that makes the tuning cord a little bit sticky and grip the tuning wheels better? Any other suggestions? I expect this has not been moved for years and may loosen up with continued use........
Thanks all.
Tom


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PostPosted: Sat Sep 09, 2017 10:52 am 
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Joined: Sat Jul 04, 2009 6:08 pm
Posts: 18449
Location: Montreal, QC, CA
There is usually a small tension spring on those strings that may have gone slack. Or, as you have deduced, the string/tuning wheels may have become dusty/slippery with age. I have had good success cleaning them with a DRY cloth (NO cleaning products) and a good rub, but the old timer tuner techs have many other tricks to get thse tuning mechanisms worling right again.


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PostPosted: Sat Sep 09, 2017 11:28 am 
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Joined: Mon Aug 08, 2016 5:46 pm
Posts: 300
Location: Markham, ON, CA
Thanks Marc. I have already cleaned the cord and the rear (plastic) pulleys. The cord is wrapped three times on the tuning knob on the front fascia. It is here that the cord is slipping.....I will re-tension the cord as it does go slack during movement.....if I tension the string with my finger, all seems to work.

Just the challenges one sees when bringing a long-stored piece of equipment back to life.

EDIT: I re-tensioned and cleaned the cord with lacquer thinners. Now it is really slipping; there is only one way to make something right, but soooo many ways to make it worse! :roll:

I now need to re-wax (or rosin) the cord. What do you recommend?

Thanks, Tom


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PostPosted: Sat Sep 09, 2017 2:01 pm 
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Joined: Wed Jul 23, 2008 9:28 am
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Location: Kamloops, BC, CA
I used dental floss once, worked like a charm.


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PostPosted: Sat Sep 09, 2017 3:30 pm 
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Joined: Fri Feb 11, 2011 9:30 pm
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Location: Regina, SK, CA
The answer is now to re-string it with waxed jewellry making string. I found this recommendation on line and it works. Strong, grips, and important...pre- stretched. Make sure to ask about what you find if not labeled.

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Vintage has a place.....mostly in my basement.


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PostPosted: Sat Sep 09, 2017 3:41 pm 
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Joined: Sun Oct 02, 2011 3:20 pm
Posts: 42
Location: Port Coquitlam, BC, CA
Lacquer thinner is a very strong solvent. You just made things worse. Applying lacquer thinner might make it stretch even more and possibly melt it. Keep oil like DeoxIT away from the string. I'll check my TU-999 later and figure out the mechanism, etc.

Here it is.
Image

Mine has no issue moving across the dial. It makes that screeching sound as if it is tight. It is actually.

Compare your unit's spring if it is the same length as mine. If yours looks like it has no tension with the spring almost fully retracted, I suggest the following steps.

- you take pictures of the string path for reference
- put a green painting tape on both AM and FM plastic wheels that holds the rest of the string on opposite ends to prevent it from getting loose.
- use tweezers to free up the end of the spring that is hooked up to the plastic wheel on the FM front end
- tie one knot as close as possible towards the spring. The idea is to create more tension. It is tempting to remove the existing knot and do it from there but I advise you not to. It is secured by a special glue.
- if you need more tension, one more knot.


Attachments:
TU-999_tension_spring.jpg
TU-999_tension_spring.jpg [ 136.15 KiB | Viewed 436 times ]


Last edited by ej251awd on Sat Sep 09, 2017 7:14 pm, edited 1 time in total.
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PostPosted: Sat Sep 09, 2017 6:25 pm 
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Joined: Mon Jun 18, 2007 8:22 am
Posts: 75
Location: ontario, ON, CA
Nice tuner, but you did absolutely the wrong thing, I don't think you can fix what you did, maybe 4 turns or 5 on the tuning knob if you you do it
(Maybe talcum powder, but I wouldn't bet on it)


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