Scratchy RF gain knob on 535D
 

Hello all,

I took a break from SWL for a few months (competing obsession), and
when I went to listen a couple of nights ago, I got a scratchy sound
from the speaker when adjusting the RF gain knob. On stereo
equipment, when that happens I pull the offending knob off, and spritz
the pot with some Radio Shack Tuner Control Cleaner & Lubricant.
However, I don't want to start spraying stuff into my good SW radio
without finding out what the risks, if any, are.

The radio is a JRC NRD-535D, bought on EBay about a year ago. Until
now it's been working pretty well. Is the spray cleaner the way to
deal with this problem? Or is there a better way to deal with it?
What do you all recommend?

Thanks,

DWP

Scratchy RF gain knob on 535D
 

labtech_one wrote:
You can use contact cleaner, or just plain ole WD40, spray and work
the control back and forth a few times to break loose the
'dirt' and then spray again to rinse it away. Wait about 1 hour,
for the spray to dry, before using the radio again. WD and some
contact cleaners are a) flamable and/or b) conductive


"CelticDude" wrote in message
...
Hello all,

I took a break from SWL for a few months (competing obsession), and
when I went to listen a couple of nights ago, I got a scratchy sound
from the speaker when adjusting the RF gain knob. On stereo
equipment, when that happens I pull the offending knob off, and spritz
the pot with some Radio Shack Tuner Control Cleaner & Lubricant.
However, I don't want to start spraying stuff into my good SW radio
without finding out what the risks, if any, are.

The radio is a JRC NRD-535D, bought on EBay about a year ago. Until
now it's been working pretty well. Is the spray cleaner the way to
deal with this problem? Or is there a better way to deal with it?
What do you all recommend?

Thanks,

DWP


Huh? How hot a spark can you make with 6 V?

Scratchy RF gain knob on 535D
 

"David" wrote in message
...
labtech_one wrote:
You can use contact cleaner, or just plain ole WD40, spray and work
the control back and forth a few times to break loose the
'dirt' and then spray again to rinse it away. Wait about 1 hour,
for the spray to dry, before using the radio again. WD and some
contact cleaners are a) flamable and/or b) conductive

I strongly recommend using the appropriate Caig product (available at Radio
Shack) rather than WD-40 or a solvent chosen at random. That will help
ensure that it stays clean and properly lubricated after the cleaner dries.


Huh? How hot a spark can you make with 6 V?

You can certainly make a spark with 6 volts. It's unlikely to happen in an
RF gain control.

Scratchy RF gain knob on 535D
 

In article ,
ess says...
"David" wrote in message
...
labtech_one wrote:
You can use contact cleaner, or just plain ole WD40, spray and work
the control back and forth a few times to break loose the
'dirt' and then spray again to rinse it away. Wait about 1 hour,
for the spray to dry, before using the radio again. WD and some
contact cleaners are a) flamable and/or b) conductive

I strongly recommend using the appropriate Caig product (available at Radio
Shack) rather than WD-40 or a solvent chosen at random. That will help
ensure that it stays clean and properly lubricated after the cleaner dries.


Huh? How hot a spark can you make with 6 V?

You can certainly make a spark with 6 volts. It's unlikely to happen in an
RF gain control.




Don't use WD40! Use DeOxit, or regular old control cleaner instead. If
the pot is bad, it's not all that hard to replace it.

BDK

Scratchy RF gain knob on 535D
 

mc wrote:
"David" wrote in message
...
labtech_one wrote:
You can use contact cleaner, or just plain ole WD40, spray and work
the control back and forth a few times to break loose the
'dirt' and then spray again to rinse it away. Wait about 1 hour,
for the spray to dry, before using the radio again. WD and some
contact cleaners are a) flamable and/or b) conductive

I strongly recommend using the appropriate Caig product (available at Radio
Shack) rather than WD-40 or a solvent chosen at random. That will help
ensure that it stays clean and properly lubricated after the cleaner dries.


Huh? How hot a spark can you make with 6 V?

You can certainly make a spark with 6 volts. It's unlikely to happen in an
RF gain control.



I know you can make a spark; is it enough to ignite light oil? Naptha
perhaps...

I work in an electronics lab facility where we use every kind of cleaner
there is. We've never waited an hour to avoid explosions from the
De-Ox-It or the WD-40.

Scratchy RF gain knob on 535D
 

On Jan 8, 8:24 pm, David wrote:
mc wrote:
"David" wrote in message
...
labtech_one wrote:
You can use contact cleaner, or just plain ole WD40, spray and work
the control back and forth a few times to break loose the
'dirt' and then spray again to rinse it away. Wait about 1 hour,
for the spray to dry, before using the radio again. WD and some
contact cleaners are a) flamable and/or b) conductive

I strongly recommend using the appropriate Caig product (available at Radio
Shack) rather than WD-40 or a solvent chosen at random. That will help
ensure that it stays clean and properly lubricated after the cleaner dries.

Huh? How hot a spark can you make with 6 V?

You can certainly make a spark with 6 volts. It's unlikely to happen in an
RF gain control.

I know you can make a spark; is it enough to ignite light oil? Naptha
perhaps...

I work in an electronics lab facility where we use every kind of cleaner
there is. We've never waited an hour to avoid explosions from the
De-Ox-It or the WD-40.

Thanks to all the responses. I had a couple of responses come
straight to my email, and they both recommended just turning the knob
back and forth. This did work a bit. Good to know I can use the
control cleaner too, if necessary.

DWP

Scratchy RF gain knob on 535D
 

I know you can make a spark; is it enough to ignite light oil? Naptha
perhaps...

I work in an electronics lab facility where we use every kind of cleaner
there is. We've never waited an hour to avoid explosions from the
De-Ox-It or the WD-40.

Very good point. Waiting a couple of minutes, until the obvious fumes
disperse, ought to be sufficient.

Scratchy RF gain knob on 535D
 

CelticDude wrote:
On Jan 8, 8:24 pm, David wrote:
mc wrote:
"David" wrote in message
...
labtech_one wrote:
You can use contact cleaner, or just plain ole WD40, spray and work
the control back and forth a few times to break loose the
'dirt' and then spray again to rinse it away. Wait about 1 hour,
for the spray to dry, before using the radio again. WD and some
contact cleaners are a) flamable and/or b) conductive
I strongly recommend using the appropriate Caig product (available at Radio
Shack) rather than WD-40 or a solvent chosen at random. That will help
ensure that it stays clean and properly lubricated after the cleaner dries.
Huh? How hot a spark can you make with 6 V?
You can certainly make a spark with 6 volts. It's unlikely to happen in an
RF gain control.
I know you can make a spark; is it enough to ignite light oil? Naptha
perhaps...

I work in an electronics lab facility where we use every kind of cleaner
there is. We've never waited an hour to avoid explosions from the
De-Ox-It or the WD-40.

Thanks to all the responses. I had a couple of responses come
straight to my email, and they both recommended just turning the knob
back and forth. This did work a bit. Good to know I can use the
control cleaner too, if necessary.

DWP

Make a 12" loop of kite string, then make a small loop in that to go
around the knob. By moving your hands slightly you can work that knob
back and forth very easily.

Scratchy RF gain knob on 535D
 

In article ,
mc wrote:
"David" wrote in message
...
labtech_one wrote:
You can use contact cleaner, or just plain ole WD40, spray and work
the control back and forth a few times to break loose the
'dirt' and then spray again to rinse it away. Wait about 1 hour,
for the spray to dry, before using the radio again. WD and some
contact cleaners are a) flamable and/or b) conductive

If the problem is good contact between the metal wiper and the carbon
or plastic resistive element, a little conductivity might not be a bad
thing.

I strongly recommend using the appropriate Caig product (available at Radio
Shack) rather than WD-40 or a solvent chosen at random. That will help
ensure that it stays clean and properly lubricated after the cleaner dries.

From the directions on their web site, "CaiLube MCL". I found it at the
local Fry's. MG Chemical's "Nu-Trol" works about the same. Lubricating
control cleaner seems to be the generic name.

I reserve the De-Oxit type stuff for cassette tape unit "Record"
switches, leaky battery holder terminals, VCR Mode Switches,
intermittent phone jack cutout switches, and the like where the
problem is cruddy metal-metal contacts.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)