sliding tuner indicator hangs up at site of lamp explosion

[chizor]

hi folks, in my model 4000 there is evidence that one of the mode lamps blew up violently. it put burn marks and some texture on the underside of the tuner rail, where a little white sleeve, possibly nylon, inside the indicator body is supposed to glide over the steel.

i cleaned the rail at length with 0000 steel wool, though access is poor, and it feels pretty damn smooth. the inner sleeve looks good and is clean. i put some silicone lubricant on the steel. however, the indicator still hangs up at that spot (it actually rotates predictably as it hits the unevenness where the explosion happened).

what is the recommended lubricant? should i try to slightly open up the indicator body? thanks for any tips.

 

[DougBrewster]

sounds like some of the material of the sleeve has adhered to the steel rail; it would feel smooth after steel wooling but has effectively increased the thickness at that point..

 

[sKiZo]

I'd think that now you've verified the problem isn't with the rail, it'd have to be he slider itself. Try pulling it back from the rail as much as possible and stuff a scrap of roofing tin or similar into the slot. If you're lucky, it's just a chunk of glass stuck in the travel path.

And not to beat ya over the head with the blindingly obvious, not a bad idea to check ALL pivot points and rollers on the string. Even if you did have a problem right in the area the lamp blew up, it's possible that having it hang there has also stressed the rest of the gear.

PS ... if you DO need to remove the dial string (or if there's any chance it might fall off) you'll be doing yourself a favor to secure the string on the pulleys where possible with painter's tape. There's about a hundred ways to route the string on a lot of these rigs, but only one that works. Leave some loose ends on the tape for easy removal.

 

[Bruno Primas]

I have used a fine grade of sandpaper effectively on a receiver that had corrosion on the track for the tuning needle. Then a little bit of electric motor oil for lubrication. (Actually, I used Hammond organ oil).

The trick was, to keep the sanding dust to the area of the track so it doesn't get on the faceplate or inside the unit. I believe I held a piece of stiff paper under the area where I was sanding. Then I cleaned off the track completely before oiling. Worked smooth as silk.