Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: [1] 2 3 Next   Go Down
  Print  
Author Topic: CLEANING UP VARIABLE CAPS IN DIRTY OLD AMPLIFIERS?  (Read 2313 times)
N6QWP
Member

Posts: 776




Ignore
« on: February 07, 2019, 11:03:15 AM »

Seeking input on what to use on another old amplifier (Collins 30L-1) that is very dirty.  Have used KrudKutter in the past, but found that the variable capacitors seemed to discolor and even corrode somewhat over time after having been sprayed, rinsed and dried.

While the KrudKutter worked very well on most of the amps and other radios, wondering if there is a better spray of some kind that does not require rinsing with water when finished-especially for the caps....OR....a product to follow up with (immediately afterwards)?

Since there is high voltage and the risk of arcing on the variable caps in an amplifier, I would like to find a proven product that will rid the surfaces of any crud, nicotine and anything else that contaminates....and hopefully leaves them as new.

Something that could follow the normal use of KrudKutter and rinse (to eliminate the problems of air and water on the plates) would probably be ideal.....as when first cleaned with the KrudKutter, the results seem great.  

This time of year, it is very difficult to properly dry out a rig that has been rinsed with water.  No hot sunny days to help.

Automotive sprays, or electronic sprays (by name)?
« Last Edit: February 07, 2019, 11:24:47 AM by N6QWP » Logged
G3RZP
Member

Posts: 1313




Ignore
« Reply #1 on: February 07, 2019, 02:01:43 PM »

In the days of analogue VFOs, some people found that an ultrasonic cleaner really worked well, although you have to physically remove the cap and re-lubricate the bearings afterwards. I figure that would work well with the 30L1 capacitors, although I know from experience it's a bit of a PITA getting them out.
Logged
WB4SPT
Member

Posts: 782




Ignore
« Reply #2 on: February 07, 2019, 02:12:21 PM »

3M electronic cleaner aerosol.   At $25 a can, don't waste it! No residue, no water, plastics safe. 
Logged
N6QWP
Member

Posts: 776




Ignore
« Reply #3 on: February 07, 2019, 02:20:49 PM »

Thanx Peter....I am trying to find something that works.....and does not require that the amp be dismantled.  I have already taken one apart.....don't want to do that again.

Looking for a "Spray and Rinse" type of cleaner that doesn't encourage corrosion.

An "After Rinse" type of flush for the variables is what I am hoping someone has found that works well.  Some product that replaces any moisture....and lubes the plates.....WITHOUT leaving any residue to attract further dirt or dust.
------------------------------------------------------------------------------

While I was typing, WB4SPT suggested the 3M product.  Thanx for that.  

David, would you use that "After the KrudKutter scenario"......OR....instead of?  I will be using the KrudKutter for the rest of the amp's insides, and will invariably get water onto the caps' plates.
-------------------------------------------------------------------------------

Would like to find a similar product that is available at about half of that cost.  I have four of these "Old Dogs" and would like to clean them (or "recondition" those that have already been sprayed) at a lesser expense.    

Any further ideas???

Ideally, some product that would also "Restore" the capacitor plates on those amps that have already been exposed to the ravages of spraying and rinsing (and show slight signs of corrosion).  This might have to be a different product???







« Last Edit: February 07, 2019, 02:44:20 PM by N6QWP » Logged
WB4SPT
Member

Posts: 782




Ignore
« Reply #4 on: February 07, 2019, 04:34:20 PM »

I have used krud kutter. It is very effective on smoking tar.  If that is in the plan, i see no need for an expensive spray.  But u dont want much of anything to sit on capacitor plates for long. I use a hot water rinse immediately followed by compressed air blow off. Then a long warm bake cycle. 

My 3m answer would be only for a targeted strike on the cap. 73’s
Logged
N6QWP
Member

Posts: 776




Ignore
« Reply #5 on: February 07, 2019, 05:14:20 PM »

Thanx for that Peter.....I am still looking for an inexpensive replacement for the 3M spray.  Unfortunately, with winter here, I don't have the facilities to properly dry the caps (or the entire amp itself) after the bath.

While I can blow off the rinse water with a small compressor, I don't want to put the entire amp into the gas oven.  Perhaps I will have to wait until the late spring for warmer weather....when, on a nice warm day, I can let the top of the amp chassis sit in direct sunshine.

I am still looking for a chemical spray to "cure" the caps after they have been subjected to both the KrudKutter and the water rinse.  I want something that, as said earlier, will coat and protect the capacitor plates from oxidation.....without leaving a film that will attract dust and dirt.

Anyone have any experience with some of the AUTOMOTIVE SPRAYS (available at most automotive parts stores)?
« Last Edit: February 07, 2019, 05:34:42 PM by N6QWP » Logged
N4MQ
Member

Posts: 349




Ignore
« Reply #6 on: February 07, 2019, 06:07:54 PM »

Dont forget that pipe cleaners work in the plate areas. Woody Enjoy
Logged
W9IQ
Member

Posts: 3524




Ignore
« Reply #7 on: February 07, 2019, 06:26:08 PM »

Quote
I am still looking for a chemical spray to "cure" the caps after they have been subjected to both the KrudKutter and the water rinse.  I want something that, as said earlier, will coat and protect the capacitor plates from oxidation.....without leaving a film that will attract dust and dirt.

Keep in mind that any coating will act as a dielectric with a relative permittivity > 1. This will raise the minimum and maximum capacitance which may affect your usuable tuning range.

You will also need to take care not to coat the wiper or bearing areas as this could render it useless.

- Glenn W9IQ
« Last Edit: February 07, 2019, 06:30:52 PM by W9IQ » Logged

- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
KE0ZU
Member

Posts: 469


WWW

Ignore
« Reply #8 on: February 07, 2019, 09:35:05 PM »

I used Ammonia and a 1" paint brush to clean this one, and it worked pretty well.  But it took three hours or so to do it.  

Here's before...


And here's after.   Not too bad considering.





--------

Here is another example of a cleaned chassis.   This time I experimented with a new and different method.

Looking at the variable capacitor in the second picture, you can see its spotless.   It does the same for any variable cap I've encountered.

Here is before...


And this is after the bath.


This one took about 5 minutes.   I used a pressure washer and the typical "soap" they sell to use in them.  



After I did this and saw how it came out, I pulled a few more out of the queue and did them as well.   Again the big variable capacitors came out looking absolutely new.   This Viking II looked easily as dirty and nasty as the receiver above, but you would never know it, by the way it looks now. 



This poor HT37 example has a badly pitted chassis so it's just going to be a driver, with no attempt to any more cosmetics.


I rinsed all with distilled water, blew them out with an air hose, and sat them in the sun for a couple days.   This saves several hours work each, and the results are equally as good.

Now I know whats "next" is already clean, which makes a big difference.


 
« Last Edit: February 07, 2019, 09:59:12 PM by KE0ZU » Logged

Regards, Mike
https://mikeharrison.smugmug.com/
Pics and bold print are usually links.
AC5UP
Member

Posts: 4546




Ignore
« Reply #9 on: February 08, 2019, 03:18:16 AM »

Two concepts to chassis cleaning come to mind...

On a lightly soiled chassis wipe out as much gunk as possible with diluted 409 type cleaner and give it soak time between wipings.  Mild cleaner / maximum working time / minimum surface damage.

For a more difficult level of gunk, especially if there's any oiliness about it, I'd try a bit of auto carburetor cleaner on a cotton pad in an obscure part of the chassis as a test.  If it works well, do the rest and consider a follow-up with a mild household cleaner to encourage a zero-residue job.
Logged

N4MQ
Member

Posts: 349




Ignore
« Reply #10 on: February 08, 2019, 04:09:55 AM »

I have used a pressure washer also, with care and at a moderate distance.  Avoid dials, paper components, as they can be trashed easily if your not paying close attention.  This was done in the heat of the summer and allowed to dry in the sun for several days without issue. Enjoy Woody
Logged
N6QWP
Member

Posts: 776




Ignore
« Reply #11 on: February 08, 2019, 07:18:51 AM »

Looks like I will have to wait until summer to get this one really cleaned up inside.  Nice job Mike.

Anyone try the various "hot" spray chemicals like brake cleaner, carb cleaner or other automotive types on variable caps???  Worrying about if some could be "too hot" for surrounding components and knobs or lettering on front panel???  Residue???  Warnings???

Will have to postpone using water rinses until a time when we once again have hot sunshine that will help with the drying.  Thanx for the input so far.
« Last Edit: February 08, 2019, 07:27:49 AM by N6QWP » Logged
KD0REQ
Member

Posts: 2399




Ignore
« Reply #12 on: February 08, 2019, 08:09:50 AM »

brake cleaner, etc. will absolutely devastate plastics.

isopropyl alcohol has been my go-to for years... but seeing how household ammonia has done some small jobs, I'm using it more.  you will have to relubricate after any severe cleaning, and neutralizing with either iso or distilled water.
Logged
N6QWP
Member

Posts: 776




Ignore
« Reply #13 on: February 08, 2019, 04:38:41 PM »

Will definitely have to wait for hot weather to flush the insides of amp using water, after cleaning it.  Today, I removed and sprayed and cleaned the outside cabinet (which was really filthy and scratched.  After using a used green pad to dislodge the many layers of dirt, I flushed the whole cabinet inside and out with cold water from the outside hose.

Even after wiping it down, shaking it and bringing it inside to a warm environment, it still has lots of water trapped in the many holes in the cabinet.  This is definitely not the time to use any water on a cleaning project.  Am planning on sanding and spray painting the entire cabinet and ring as soon as the temperature gets back to warm enough levels for the paint to set up properly.

I might just try some ammonia and rubbing alcohol, after the rain stops....to see what they can accomplish on the chassis and many components.  If that seems to do a good job, I might resort to using the KrudKutter and following it up with flushing using those products instead of water.  Will definitely have to use a hair dryer to thoroughly dry out the chassis and parts.

If I can get some feedback on an automotive chemical cleaner that will not leave any residue, I can restrict it's use to just the two variable capacitors and the band coil (without subjecting any of the panel or knobs or meter to it's harsh effects).
« Last Edit: February 08, 2019, 04:49:57 PM by N6QWP » Logged
AC5UP
Member

Posts: 4546




Ignore
« Reply #14 on: February 08, 2019, 08:24:11 PM »

No need to wait until summer...  Is there any place in the house where you can park it for a day or two near a heating register?  For small items I've had excellent luck with the warm spot above the pilot light of a gas range.  30 minutes or so and it's dry.

Ammonia is inexpensive almost anywhere.  At my local home & ranch supply store a gallon of white ammonia (or vinegar) can be had for $3.00 or so and a gallon goes a long way.  Rare that I use it straight, for cleaning a 50 / 50 cut seems about right.  If you have water stains you can ease them out with vinegar if allowed to soak for a few hours.  Check and agitate the part a few times during the process.  And while you have the bottle open run a cup or two of a 50 / 50 mix through your coffee maker.

As mentioned above, brake or automotive electronics cleaner will damage plastics so I recommend carbuerator cleaner instead.  Spray into a cotton cosmetic pad and use the pad as a wipe-on instead of a direct spray.
Logged

Pages: [1] 2 3 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!