Bulb replacement in ‘52 Valco amp

[Doclinz]

Picked up a nice ‘52 National 1215 amp (Valco made) that has/had tiny light bulbs to backlight the plexi panel over the backpanel controls.

I guess I could see what happens via trial and error, but wondered if anyone had any suggestions. Nothing spec’d in schematic; no markings on the remaining bulb in the chassis; No idea what voltage involved.

Will try to post photos.

[martin manning]

Like this? See second photo here https://reverb.com/item/186481-1951-nat ... mp-no-1215 Those look very much like #47 6.3VAC bayonet base lamps. Detailed specs are here: https://www.bulbtown.com/47_Miniature_B ... _p/b47.htm

[Doclinz]

Thank you very much!

Looks like the tweed upper panel helped bounce the light into the plexi panel a bit. The lone bulb in mine is indeed bayonet type, and I guess I should have surmisedr measured 6.3 VAC (doh!). The bulb itself is round rather than elongated (probably helps position it behind the panel).

Armed with your info, I’ll try to track these down. Thanks again.

[Doclinz]

Looks like the G3.5 shape round bulb is not available for #47. Think this is part of the reason upper panels left off as there’s no clearance beyond the bulbs. Only alternative I can find is a 7 V auto bulb.

[sluckey]

7 volt bulb will work just fine on 6.3V. Will this Eiko bulb work?

[martin manning]

I'm guessing if the original bulb was a G3-1/2, it was a #130, 6.3V, 150mA. https://www.ebay.com/itm/183740327916

[Doclinz]

Thanks. From one Martin to another…

-Martin Lindsay

[Doclinz]

Here’s the remaining bulb for reference