"S" unit panel mounted meter

[UDX-4570]

Hello crew:
This is new to me, this S meter has 4 posts on the back, the large ones have a + and - marked on the meter, the two small ones have the letter "L" marked on the meter next to the posts.

This meter is a N.O.S. made in Japan, a very nice meter I must add, but as for the two small posts, not exactly sure what they are for. If anyone has any knowledge about this, feel free to chime in.

UDX-4570 Palm Springs wavin!️

 

[TM86]

No knowledge, just a guess. "L"ight? As in power for a lightbulb to illuminate the meter?

 

[sp5it]

Probably backlight.

 

[UDX-4570]

Probably backlight.

I was thinking the same thing, but I can't see it being AC power, or maybe the manufacturer expects you to use the + or - on the large connections as a reference???

Thank you for the reply.
UDX-4570 Palm Springs wavin ️

 

[UDX-4570]

No knowledge, just a guess. "L"ight? As in power for a lightbulb to illuminate the meter?

If that's the case, there is no polarity and AC powered, the only + and - markings visible are on the large posts. IDK, I'll keep searching the net to see if I can get a positive identification on the posts.

Thanks for the reply!
UDX-4570 Palm Springs wavin!️

 

[nomadradio]

The big posts are for the meter coil.

The small ones lead to a tungsten lamp that cares not about polarity. Was probably meant to use the 6.3 Volts AC that lights up the tube heaters.

73

 

[BC Coyote]

Was probably meant to use the 6.3 Volts AC that lights up the tube heaters.

I've seen both 6 volt and 12 volt lighting in older meters. With various types of bulbs. Though most older meters I see are unlit.

 

[UDX-4570]

The big posts are for the meter coil.

The small ones lead to a tungsten lamp that cares not about polarity. Was probably meant to use the 6.3 Volts AC that lights up the tube heaters.

73

Y your correct, I figured it out, they are low voltage contacts for the back lighting.