Did you replace 9090 Power Meter bulbs ?

shouldn't each of the LEDs have it's own current limiting resistor?

You should be able to get away with one resistor? - providing the volt drop and current has been correctly accounted for. Also I see now that it may be one bulb or LED for each side of each meter. (4 bulbs / LED's ?)
 
Each meter has two bulbs, one on either side of the meter. The bulbs in each meter are wired in parallel and fed through a 10 ohm resistor.

- Pete
 
If I can add to the thread, this was the best and most accessible method without desoldering boards or dismantling the receiver. I cut the 2 black & white power wires and loosened the brown wire from the clips from the underside to allow more room to move the assembly. Using a Dremel with the area taped off like a clean room and a vacuum hose close by, I cut a slot in the bar so it can be bent slightly to allow the meter assembly to be moved out. Now the wires, circuit board and bulbs are pretty accessible. Got my bulbs on eBay which where rated at 6v, 3mm and 68ma as I prefer incandescent color temperature. Replacing all 4 guaranteed matching brightness and longevity before needing replacing. This method does not keep the receiver totally stock original, but it saves a lot of grief.
 

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I don't like the LEDs either, anywhere in the receiver the incandescent bulbs last 20 years. before they will need to be replaced.:):eek2:
 
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jus
 
Hey there, digging up this old thread because out of the few others, this has the most information. I have pulled the meters out, and want to replace the bulbs with led lights. I read that I should use a 200 ohm resistor, could someone maybe link me one that would be appropriate? Is a 200 ohm resistor agreed the appropriate value? Thanks. I just finished my restoration and blew the lamp on my first test run.
 
It's not that simple. LEDs are diodes. They don't have an internal resistive load like an incandescent bulb. A circuit to power an LED needs a dropping resistor to limit current across the diode junction. To determine the value of that dropping resistor, you need to know the current requirements of the LEDs you plan to use. That information should be on the data sheet for the LEDs. Once you have that, you can plug the values into a LED resistor calculator like this one to get the correct value.

Do you have the specs for your LEDs?

- Pete
 
It's not that simple. LEDs are diodes. They don't have an internal resistive load like an incandescent bulb. A circuit to power an LED needs a dropping resistor to limit current across the diode junction. To determine the value of that dropping resistor, you need to know the current requirements of the LEDs you plan to use. That information should be on the data sheet for the LEDs. Once you have that, you can plug the values into a LED resistor calculator like this one to get the correct value.

Do you have the specs for your LEDs?

- Pete

And since the lamp circuit is AC voltage, and the bulbs are in parallel with the dropping resistor, wouldn't you want to install the 2 LEDs in opposite polarity to reduce the flicker?
 
I've never noticed any flicker so I don't think it's an issue. Also, I don't think you want to install LEDs in parallel with a single dropping resistor. If you put them in series, you can use a single dropping resistor otherwise they should each have it's own resistor.

- Pete
 
A quick search turned up this reference.

- Pete

That link is for using DC voltage. The meter lamps run on AC and the diode will "flicker" each half cycle, though for some it isn't really noticeable. I myself do see the flicker. This video by xraytonyb shows him installing the LEDs out of phase, and using a 220 Ohm resistor on each LED. Skip to about the 20 minute mark since he's a bit long winded. :blah::D
 
I like his videos. I've watched several of them. He's long winded but knows his stuff. Hadn't considered wiring them out of phase but it makes sense.

- Pete
 
I understand that the power meters have a 10 ohm 1/4 watt resistor, but what is the tolerance, 5% or 10%?
Can anyone enlighten me on this doubt?
 
Seems like the best place to ask this question: has anyone found/sourced replacements for the small grommets that hold the bulbs (incandescent, original) in the holes in the back side of the VU meters? I need some as mine are pretty crumbly. Or, any ingenious soul come up with a retrofit design?
 
Seems like the best place to ask this question: has anyone found/sourced replacements for the small grommets that hold the bulbs (incandescent, original) in the holes in the back side of the VU meters? I need some as mine are pretty crumbly. Or, any ingenious soul come up with a retrofit design?

A grommet?

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Seems like the best place to ask this question: has anyone found/sourced replacements for the small grommets that hold the bulbs (incandescent, original) in the holes in the back side of the VU meters? I need some as mine are pretty crumbly. Or, any ingenious soul come up with a retrofit design?
Silicone grommets for tattoo machines work for me and fit perfectly. There are small differences between them but still work fine for the bulb size.
 
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