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]   Go Down
  Print  
Author Topic: Meter Won't Reset to Zero  (Read 2178 times)
K3ZD
Member

Posts: 174




Ignore
« on: April 21, 2017, 04:08:33 PM »

I've been given an SWR meter that has not been used in years.  It works but the meter will not reset to zero unless I tap on it. 
Logged
W6ARY
Member

Posts: 48




Ignore
« Reply #1 on: April 21, 2017, 05:46:42 PM »

Are you wanting to fix it or just sharing your experience?

---Gary (W6ARY)
Logged
K3ZD
Member

Posts: 174




Ignore
« Reply #2 on: April 21, 2017, 05:57:02 PM »

Are you wanting to fix it or just sharing your experience?

---Gary (W6ARY)

Yes.  Or perhaps I should say - I'd like to know how to fix it. 
Logged
KD0REQ
Member

Posts: 2005




Ignore
« Reply #3 on: April 21, 2017, 07:11:42 PM »

two possibilities.

one, static charge... put a little dishwashing liquid on a cloth and gently rub the meter face.

two, somebody whacked the needle hard against the stop and broke the suspension.  for that, you need a new meter.
Logged
AC5UP
Member

Posts: 4403




Ignore
« Reply #4 on: April 21, 2017, 07:19:42 PM »

The obvious answer is a sticky meter movement, like the pivot bearings are either dirty or binding due to a mis-alignment.  (Translation:  Been dropped once)

Usually a meter is reasonably well sealed against dust intrusion but it is possible for a chain smoker to add a thin layer of nicotine residue to the innards.  Also possible the family thrived on fried foods and there is some vegetable oil condensate in exactly the wrong place.  Bottom line is you can develop the habit of tapping the meter when needed or open it up for a little clean & lube.

If you break it try to remember it was a gimme......    Cry
Logged

WA3SKN
Member

Posts: 6476




Ignore
« Reply #5 on: April 22, 2017, 02:36:02 PM »

Glass or plastic face?  Are you using it in a horizontal or vertical position?
It sounds like a little dry silicon spray might be in order for the movement, but there are a lot of variables for meters.
How delicate are your hands?

-Mike.
Logged
K8AXW
Member

Posts: 6222




Ignore
« Reply #6 on: April 23, 2017, 09:37:32 AM »

If the "dish washing detergent" doesn't do it, resort to the fact you have to tap it to get it to return to zero.

I have one like that and since the meter is now "unobtainium" I would never consider opening it up and definitely not using spray cleaner on it.  I had a friend whose shack was involved in a flood and the meters on all of his gear was filled with muddy water.

I disassembled them and cleaned them and believe me, it was  very delicate and time consuming job. In some cases it required more than one tear-down and cleaning!

In your case, I'd try the detergent routine or live with it.  (assuming of course that the meter can't be replaced)
Logged
K2OWK
Member

Posts: 1267




Ignore
« Reply #7 on: April 23, 2017, 09:51:04 PM »

Check to see if the meter needle is slightly bent toward the face of the meter. I had one with a similar problem where the needle touched the face as it came to the zero position. I removed the plastic face and bent the needle slightly forward. This fixed the problem.

Hope this helps.

73s

K2OWK
Logged
KAPT4560
Member

Posts: 377




Ignore
« Reply #8 on: April 24, 2017, 01:03:23 AM »

 Meter repair is like watch repair. Very delicate work. I would not spray anything into it and plan your disassembly before you start.
 Some old gear of mine had hermetically sealed meters where internal out-gassing from the foam rubber over the decades had formed a white powder (formaldehyde?) between the armature and magnets.
 Gentle cleaning and blowing removed the interference. Use non-magnetic tools.
Logged
WA3SKN
Member

Posts: 6476




Ignore
« Reply #9 on: April 24, 2017, 07:20:55 AM »

Yes, there are physical adjustments, magnetic adjustments, etc plus you are working with jewelled movements.  And, you can probably get a replacement meter.  How familiar are you with working within a meter movement?

-Mike.
Logged
W6EM
Member

Posts: 1615




Ignore
« Reply #10 on: April 29, 2017, 05:52:29 PM »

I once had some success in adjusting the jeweled bearings of an old meter.  Since I acquired it in used condition and probably having been dropped by its former owner, its movement was sticking.  I think that was caused by the armature dragging against one of the magnet poles.

On each end, there were two locking nuts.  I could see that one end of the shaft had come out of its bearing.  I loosened the locking nut and with a very small screw driver, backed the bearing set screw out so that I could realign the shaft and reinsert it into its bearing jewel.  I then tightened the bearing jewel just enough so that the meter movement would not drag and tightened the locking jam nut.  The meter worked well after that.

I used a magnifying lens lamp, as I would not have been able to see the movement well enough to have made the repair.

Good luck with yours.

73.

Lee
Logged
Pages: [1]   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!