Zenith replacement bulb, 1982 model R421.

[scotlawrence]

Hey everyone, im working on my 1982 Zenith R421:

(I believe the '82 R421 is Zenith's very last table radio.)

Ive taken it apart to clean it, and I want to try to replace the bulb..
The bulb for the lit tuner display is dead:

It has only the one bulb..
I would like to replace it..
The wrapper around the bulb clearly says:

KUKJAE

But unfortunately that means nothing to Google.
The bulb is 3/16" in diameter, about 5mm.

1. Anyone know the bulb model?

2. It has a dab of white paint on the end, for light diffusion, so the light goes more out the sides and less out the front, to make more even light across the dial. If I can find an incandescent bulb that fits, what kind of paint could I use to dab on the end like the original bulb?

3. Should I consider LED? I would like to keep it original if possible, (this radio wont get a lot of use) but im not totally opposed to LED.

thanks!
Scot

 

[redk9258]

What voltage is it? Is there a schematic or service manual available?

 

[scotlawrence]

There is a manual! I found it on ebay..should have it in a few days. I dont know if it will have a schematic.

Thanks,
Scot

 

[scotlawrence]

Ok, I got the manual! The bulb is:

Part No. 900-360, pilot lamp, 6V 30mA.

Anyone have a suggestion for a modern replacement bulb of the correct size?
And anyone know what kind of white paint would be best?

Thanks,
Scot

 

[toxcrusadr]

Is that soldered to those leads under the tape or did it come with leads incorporated into the bulb? i.e. going straight into the glass.

I'm thinking two possible sources, one might be the usual electronics suppliers (Mouser, Digikey, etc.), the other would be bulb suppliers like 1000bulbs.com, Top Bulb.com.

You have all the parameters: voltage and current, diameter. Except maybe what type of bulb it's supposed to be called.

 

[toxcrusadr]

https://www.topbulb.com/sylvania-2112d-bulb-0-2-amp-6-3-volt-t1-75-wire-base

https://www.mouser.com/Optoelectronics/Lamps-Holders/Lamps/_/N-5g6r?P=1z0ys5rZ1z0yt45Z1z0w8s5

I'm not familiar with the sizing scale here (T1.5 etc.) so these may be way off.

Mouser lets you select filters and that second link is a stab at what you're looking for, there were 5 possible matches.

Nothing I've seen has that dot of paint though.

 

[redk9258]

I believe you are looking for T1 1/2. I would try AudioKarma member Dave Wojo ... https://sites.google.com/site/dgwojocom/

 

[BinaryMike]

J-B Weld epoxy should work well for the paint spot. It's rated for operating temperatures up to 550F.

 

[scotlawrence]

Thanks guys! much appreciated..

I believe you are looking for T1 1/2. I would try AudioKarma member Dave Wojo ... https://sites.google.com/site/dgwojocom/

Dave says he is out of the office until 1/26..I'll send him an email this weekend..
thanks,
Scot

 

[maxhifi]

https://www.topbulb.com/sylvania-2112d-bulb-0-2-amp-6-3-volt-t1-75-wire-base

https://www.mouser.com/Optoelectronics/Lamps-Holders/Lamps/_/N-5g6r?P=1z0ys5rZ1z0yt45Z1z0w8s5

I'm not familiar with the sizing scale here (T1.5 etc.) so these may be way off.

Mouser lets you select filters and that second link is a stab at what you're looking for, there were 5 possible matches.

Nothing I've seen has that dot of paint though.

For sizing lamps, T means tubular shape, and the number following this, is increments of 1/8 inch.

For example, a T8 lamp is 8/8 or 1 inch in diameter, a T4 bulb is 4/8 or 1/2" in diameter, etc.

In your case. T1.5 means tubular and 1.5/8 or 3/16 in diameter, so yes, it is correct.

 

[toxcrusadr]

Ah, I should have known that about the 1/8" increments since my shop is full of T8 and T12 tubes and I had to learn that.