Scratchy RF Gain Control

[KB2WIF]

I need to replace an RF Gain Control Pot on my Kenwood TS-130S Xcvr. Anybody know where I can obtain one. The one on it now skips when I turn it.

Would appreciate any help.

Mike, KB2WIF
Treasure Island, FL

[WA8RTI]

Not sure you have to replace the pot. You may be able to still buy pressure cans of cleaner meant for cleaning control pots and TV tuners (in olden times they had mechanical contacts) I still have a very old can that came from Radio Shack and it still worked the last time I needed it. Often volume controls and other pots would become become noisey or skip and the cleaner would solve the problem.

[KA9VQF]

You can try the cleaner suggested but I use WD-40.

Now in a few seconds there will be a bunch of folks jumping in to tell you to never use WD-40 because it leaves a residue behind that they will claim is more detrimental than just leaving the pot as it is.

I've found that many of the commerical cleaners actually make the pot dryer than it was which causes it to actually work worse.

I’ve been using it for many, many years and still have to see where it is a bad product. Sure in a few years you may need to squirt the pot again but I am convinced that you might to retreat it no matter what product you use.

[W6VPS]

-Anybody know where I can obtain one-
Specifically no...but here's how I'd try tracking donw a replacement. Since it is a 20+ year old rig I'd bet the actual control is pretty close to industry standard in terms of physical size and configuration.

Highly unlikely for success but try Kenwood. Worst they can say is no!
Confirm the resistance and taper of the pot. 50K - Liner taper perhaps?

Go to the Mouser, Digikey, Jameco or Newark websites and start your search.

You might also prowl 'ePay' You might find one for parts that's cheap enough to warrent a purchase.

Good luck

Paul/W6VPS

[KE6KA]

It isn't the residue that is the problem. WD-40 can actually break down the carbon on some pots, and dust sticks to it.

I use Puretronics Contact Cleaner w/silicone (Part no. 5000). I've had reasonably good results with it.

http://www.allelectronics.com/cgi-bi...T,_13_0Z_.html

Keep in mind that scratchy controls aren't always due to dust, but are quite often due to wear or oxidation. The best thing to do is replace them, but sometimes you can use the technique explained here:

http://www.repairfaq.org/REPAIR/F_au...#AUDIOFAQA_008

And repairfaq is a great resource for fixing a lot of electronic things.


http://www.repairfaq.org/REPAIR/

[KG4WPD]

Years, I mean years ago, a Popular Electronics magazine suggested for a quick fix, putting a drop of "Williams Lectric Shave" in the noisy pot. Believe it or not this really worked.
For me this little trick saved the day on more than one occasion.

That’s my two cents worth . . . Good Luck,
Tom-KG4WPD . . . 73

[AE4FA]

I've used WD-40 on occasion when the cleaner was all gone and have had no ill effects. I'm currently using an R$ product called Contol/Contact Cleaner and Lubricant. It does a nice job.

[M3JZT]

I usually clean with a good contact cleaner,...if this doesn't work then a squirt of wd40,...leave this for a while then give another squirt of contact cleaner....but maybe the switch is caput,..it may be worth a look at the switch it self bye taking apart very carefully and checking inside,...making sure all is OK in the innards..clean with contact cleaner,..then re assemble the switch....this probably means un soldering the wires to the switch,..make a note of the colour and position of the wires before you take them off..then if this is the same try a new switch....

[K9STH]

The "olde tyme" TV repairmen used to use WD-40 to clean and lubricate the old turret-type television tuners without any adverse effects. In fact, WD-40 often worked better than any of the cleaner type products on the market at the time.

Frankly, I use WD-40 all the time to clean switches, potentiometers, etc., on both "boat anchor" and "modern" equipment. In over 40 years of doing such I have never had any problems. Now there are definitely a few precautions that you have to follow when using WD-40 (and, for that matter, other types of cleaners) including using only a small amount of the cleaner in the proper area (that is why WD-40 comes with those small diameter red plastic tubes). Definitely do NOT spray large areas with the cleaner. Another is to NEVER spray any type of cleaner when the unit is turned on (it is best to unplug it from the wall socket or disconnect the power supply whichever is appropriate).

The only thing that you have to be careful of is on those relatively scarce units that used the very cheaply made phenolic wafers in rotary switches. With those type of switches virtually every type of cleaner (including DeOxit) will cause the wafers to "swell" and that often causes problems. Most of those units were Japanese made during the 1960s.

You definitely have to make sure that there is some type of lubrication left after cleaning, especially on switches. Otherwise they will "freeze up" in a very short period of time. WD-40 does a good job of this.

When I owned the Motorola reconditioned equipment center for the south-central United States (for almost 10 years) we used WD-40 to clean potentiometers, relays, and switches exclusively. We shipped between 75 and 100 units per "average" week and we NEVER had a single problem by using WD-40. Our warranty rate was less than 0.1 percent for any reason while new equipment from the factory averaged 7 percent during the same 10 years. Now that warranty rate covered all sorts of problems including the need for recalibration, "infant mortality" component failure, and so forth.

Now I understand that there are 2 groups of people where use of WD-40 as a component cleaner is concerned: Those that "swear at" the use and those that "swear by" the use. I definitely am a member of the latter group.

Glen, K9STH

[N9RZD]

good ole WD40