Does anyone know if the face of these meters can be removed?

Thread Starter

spinnaker

Joined Oct 29, 2009
7,830
I have an idea for a project but if I do this I am going to want to change the scale on a meter.

These have a nice retro look.

http://www.ebay.com/itm/Black-AC-0-...184645?hash=item2c9e2b1545:g:L8UAAOSwyQtVpaBp


http://www.ebay.com/itm/Round-Analo...hash=item4602321138:m:mHf9l9I1ueERlsh78fuvWiQ

Does anyone know if the faces on these meters can be removed so I can get in and replace the scale?

I figure I might need to contact the seller. But thought I would ask here first.

I have used those more modern meters with the the square face before and I know they pop off but have never used these older looking meters.
 

KL7AJ

Joined Nov 4, 2008
2,229
I have an idea for a project but if I do this I am going to want to change the scale on a meter.

These have a nice retro look.

http://www.ebay.com/itm/Black-AC-0-...184645?hash=item2c9e2b1545:g:L8UAAOSwyQtVpaBp


http://www.ebay.com/itm/Round-Analo...hash=item4602321138:m:mHf9l9I1ueERlsh78fuvWiQ

Does anyone know if the faces on these meters can be removed so I can get in and replace the scale?

I figure I might need to contact the seller. But thought I would ask here first.

I have used those more modern meters with the the square face before and I know they pop off but have never used these older looking meters.
Yes. There are probably three tiny screws near the back. REmove those and the entire mechanism will slide out of the cylindrical "shell." Be very careful not to bend the needle in the process of removing it. The same goes for replacing the meter face. That stuff is DELICATE

Good luck!
Eric
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,830
Yes. There are probably three tiny screws near the back. REmove those and the entire mechanism will slide out of the cylindrical "shell." Be very careful not to bend the needle in the process of removing it. The same goes for replacing the meter face. That stuff is DELICATE

Good luck!
Eric
Thanks! I am going to confirm with the seller but the information on the screws is going to be useful to help them to determine if it is removable.

Yep I know how delicate they can be. Have not had one apart in eons but I do remember.
 

Hypatia's Protege

Joined Mar 1, 2015
3,228
FWIW here is an example of a similar indicator -- There are generally three fasteners at 120° intervals about the circumference - Removal of the contact-post burs is (generally) neither necessary nor recommended...

Good luck!:)

Best regards
HP
Darsonval1.JPG

Darsonval2.JPG
 
Last edited:

Alec_t

Joined Sep 17, 2013
14,280
The meter in the first link seems to have cross-slotted screws in the wall of the cylindrical part. All the old-style meters I've had could be dismantled by removing screws, but a couple of recent ones have welded plastic cases.
 

Aleph(0)

Joined Mar 14, 2015
597
Meters like that used by ancient surplus and like hro com receivers which like KL7AJ, HP and Alec say held in case by three screws. I know cuz when teen I used to scrap old 40s military castoffs and sell parts for pin money;)
 

atferrari

Joined Jan 6, 2004
4,764
I may be deadly wrong but it looks like the needle must go out first and then the faceplate freed by loosening both screws.
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,830
I may be deadly wrong but it looks like the needle must go out first and then the faceplate freed by loosening both screws.
That is my fear too. I was hoping to somehow slip my own "faceplate" in behind the needle but after thinking about it, it would make trimming my faceplate to the proper size a challenge. It would also make gluing it in place problematic. I need at least 3. Wondering if I shouldn't just order one for now and see that is up.
 

Hypatia's Protege

Joined Mar 1, 2015
3,228
I may be deadly wrong but it looks like the needle must go out first and then the faceplate freed by loosening both screws.
In my experience the bottom edge of the 'scale card' is open. --- Having removed the indicator mechanism from its case, one need only remove the two screws securing the card - then slide it up (i.e. away from the pivot) and off...

BTW -- No worries Re: the 'zero trimmer' - it engages the indicator assembly via a 'pin and fork' arrangement and does not interfere with removal of the case.

Best regards
HP:)
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,830
In my experience the bottom edge of the 'scale card' is open. --- Having removed the indicator mechanism from its case, one need only remove the two screws securing the card - then slide it up (i.e. away from the pivot) and off...

BTW -- No worries Re: the 'zero trimmer' - it engages the indicator assembly via a 'pin and fork' arrangement and does not interfere with removal of the case.

Best regards
HP:)
Looking at it more closely, it does look like it can be carefully slipped out from behind the needle. Thanks.
 

k7elp60

Joined Nov 4, 2008
562
I used to change scales on meters quite often. I would carefully remove the existing scale. Then I would draw a new scale on the computer, print the new scale on normal printer paper and use double sided scotch transparent tape to tape the new scale to the existing scale. Then I would use an xacto hobby knife to cut the holes in the new label, then carefully reinstall the new scale.

One possible problem if the the meter is fairly old is that the magnetism may have decreased an that my affect the accuracy of the meter.
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,830
One possible problem if the the meter is fairly old is that the magnetism may have decreased an that my affect the accuracy of the meter.
Inaccurate how? Is it inconsistent across the range of deflection? Is long as the inaccuracy is consistent then that can be calibrated correct?

Can they be degaussed? I knew I should have not thrown away my CRT degaussing coil! :(
 

Hypatia's Protege

Joined Mar 1, 2015
3,228
Inaccurate how?
FWIW -- While I don't claim to be an expert in this area - I can tell you that I've never observed 'diminished' PM field magnets in D'Arsonval movements...

Can they be degaussed?
Please don't try that! -- If it did anything it would further weaken the field - to say nothing of the violence it would 'visit' upon the indicator needle!:eek:

Seriously, as long as the units have not experienced gross mishandling you should have no problems!:)

Best regards
HP
 
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