[David]

The old XMAS bulb was a C-7 app 7 watts there is a bayonet base bulb used in sewing machines and vacuum cleaners same wattage but a bayonet base. Try a shop that works on sewing machines, and they now make led bulbs in that size but they are not cheap. bulb voltage is 120 volts

[David]

Found your bulb   https://www.amazon.com/Dritz-Sewing-Mach...2B15w&th=1

[jcassity]

naw,, nothing like it..
its like the base of an 1156 automotive bulb.

the oem single socket i would like to keep and duplicate that on the other side of the speaker but there is no room for something of that size.

i took the radio apart again today and finally got to replace my .0005 cap. apparently that repair made my lower FM bands come right on in so all is looking realy good. this set is too nice to have in the garage, and its a really great player. the wife wants it in the kitchen for rock station on FM.

i am tempted to feed 120v into a wall wart power supply that sits inside the chassis then the output will be 12vdc,, i would use the existing light feed path for the wall wart power supply ,,, then i can use smaller automotive 194 bulbs / sockets and i can use yellow to complement the intent of the yellow "ish" riings around the knobs.

what i do know is that the 120v pair of wires to the oem bulb need replaced, they are all really cracked.

using 194 bulbs will be 80% smaller than this big old bulb for sure.

then again, i know laying a wall wart power supply

[Arran]

The schematic shows and specifies a neon lamp, PL-1, so that would explain the dual contacts, it's basically right across the power line in series with a current limiting resistor. So no doubt that the dial had an orange glow to it at one time.
Regards
Arran

[jcassity]

no,, you may be looking at the wrong diagram, its a zenith pn 100-97,,, not neon.

i attempted to train my dc out on the Sel Rect and was able to use 60mg parallel branch to get 14vdc to power 194 bulbs. the problem is when i power up,,,, the 194 bulbs blow. i will try a couple more things today but .... i need my new bulb to be very low profile to achieve what i am attempting to do.

[David]

Could you add a LM317 adj. voltage reg to keep from blowing the bulb?

[jcassity]

i thought i had those but  i dont.
i reverted back to using 120v to power the lamp but now i can say "lamps".

i found the original bayonet bulb at lowes which the base is equal to an automotive 1156 bulb.... but i am using small screw in bulbs now with new sockets all soldered in and working.

two issues
-the left lamp is too close to the case and even with my metal tape on the interior to mimic the original design on the right side, the case just gets way too hot.  i will have to rework the lamp location or use a smaller profile bulb.  both new bulbs are 15watt,, the original single bulb was 45watt.

-the lower half of FM went goofy again,, i dont think i will ever have the smarts to fix it but FM 93 on up is golden even with no rabbit ears attached.

here are some pics of the final work to properly light up the unit like i think it should be. now atleast both knobs light up well enough and the dial glass is a tad off kilter on illumination but good nuf' for me.

[jcassity]

i adjusted the left lamp and added some more heat barrier material so all is well.

i cut away some of the rubber foam that seals around the dial glass to allow light in on the dial section from the left,, it was blocked off by the foam.

is anyone interested in taking this set on to align the FM for me?

i can do the AM side but have no equipment for FM.

[mikethedruid]

If those are candelabra based screw in bulbs you are using now, they make LED replacement bulbs that would run a lot cooler. You might want to try them in this application. https://www.bulbs.com/product/LED-C7C-CLEAR?RefId=788 .

[jcassity]

a bit off but on topic.
i noticed something very very cutting edge in this radio that to me stems off a topic i am experienced with.

i keep calling this a "dial glass but its actually a louvered clear plastic.

the original application required one bulb so keep that in mind.

the engineering team solved a complicated problem with the least cost.

so,,, inside this set the plastic louver dial glass converges to a large hunk of plastic stump so to speak and at the end of this stump,,, i examined the surface which it has been actually polished. this "stump" points right at the single bulb that it came with originally.

what they were doing was using a form of tech in fiber optics.,, using light to hit the clear plastic and the assumption was the light would travel through the dial glass.
it does work somewhat but its uneven. secondly , a single bulb on the right did not light up the left translucent ring.

just thought i would post this fascinating use of early fiber optics.

[jcassity]

i am surprised no one noticed how i solved the "sticking" slug tuning issue.

i noticed that the slug tuning would sometimes not drop down all the way making me think something was broke,, a simple 5/8'' heavy nut and a zip tie fixed that. see the big orange dot on the top of the chassis.

[jcassity]

Update-- on FM 

***the picture shows the radio when the left half of the full FM dial scale as inoperative.****

problem- the FULL left half of the dial scale produced no changes in channels while on FM only.
going from the needle 12 o'clock position ccw to the 9 o'clock, one barely audible channel would dominate this ccw full 90deg sweep.

Item A consists of two dial string pulley's fixed to item B thee "CAM".  this pulley / cam system is slipped onto the tuning cap shaft and held in place by two lock screws once it is properly located and coordinated with the dial needle.

Item D is a hinged chunk of  flat metal with a round mated cam follower item C that will "follow" the item B "cam" as the tuning cap is rotated.
Item D carries three of item E FM slugs up and down into the FM coils as the tuning cap is rotated.

item F  the dial needle and pulley is currently shown approaching the max clockwise position.  note the location  of item E the FM tuning slugs are still poking up and out of the FM coils. just a tad.

I re-coordinated the tuning cap to tuning cap cam to dial string needle and now the lower half of FM receives properly throughout the 180deg needle swing.

while taking a long hard study of all the working parts, i found one item A lock screw was loose.  i also found that the pully item A was dressed too far up on the tuning cap shaft  and causing the main "driver" string to be rubbing the chassis.

i know most of you have experience working on slug tuned FM sets but this was my first go and i learned a lot but i still have a long way to go.

[EdHolland]

Good fix!

I'm taking notes, as the Zenith chassis on my workbench seems to have a very similar system for FM tuning.

[jcassity]

well,, i totally got lost on the step 2 and 3 of the AM alignment only because the column called "purpose" assumed that a qualified trained tech had the common sense to interpret the information.

that being said, i finagled the FM back into  working order but did not proceed to the FM alignment at all because things were just too darn "good nuf" for me.  

the FM slugs just simply spin by finger to adjust on that skinny threaded wire.

here's a note worthy milestone though,  got sent a legible schematic today and man am i pleased!

[LarryFS]

Great photo! Glad you are happy with it!