The PHILCO Phorum

what do you guys use?

what have you figured out that has made it more useful?

i watched a vid last night of a guy who kept his hooked up to a powered on radio ,, it went dim but over the course of many minutes of time, the side mounted volt and ammeter would react to things happening in the set and the volts would drop and current would spike,  and the bulb would quickly let out moments of glow.  to me this is something you would never be able to easily detect without a dim bulb tester.


i am considering making one,, a guy on youtube also uses 4 bulbs in parallel  (2 40w & 2 60w)  on the line hot side with a side amp and volt meter.

this got me to thinking about doing this....
line power to one side of a Pot,,, then the wiper out to the bulb, then the other side of the bulb to the hot leg input to the radio,, then the N leg back around unbroken.

i also found it interesting that one vid shows how you can use a dim bulb tester to verify your radio is not AC wired backwards.  this is something we could all do visually but........... still a nice quick visual aid.

so what do you guys do,, what do you have,,, what have you added on to make this even better?

as a side note,, in telecommunications we still use this concept when dealing with the addition of a new battery string.
example, we have a 2000A dc plant floating at -54vdc.  tied to the - & + buss work could be several 2180AH batt strings (about 7901 pounds each) all charged up and proteted by 1200A breaker disconnects on each battery stack.  to add another battery string, a portable charger is used like something along the lines of a 4kw unit.  this new battery is wired to the overhead dc buss and back to the new battery stack 1200A disconnect but the disconnect is OFF.  when the precharger gets my new string close to the -53vdc mark,, put one wire of the lamp on the hot leg of the existing battery bus and the other lamp wire on my new battery string hot bus.  if the lamp comes on,, eventually it will go out and its safe now to flip on the new battery string 1200A disconnect.

This same system was used with AC generation. When a new generator was brought up to speed, its output was connected between it's "hot" output and the output on the already running line. As the generator reached the same speed as the line, the bulb would blink on and off more and more slowly. Finally, one would keep adjusting the speed until the bulb remained out. Then the new generator would be in phase with the existing line, and one could cut its output in to the line.

Nostalgic considerations apart, for radios I find Variac more useful.

I agree with Mike (morzh).

I don't use a light bulb - for this. I built an adjustable current limited supply that meters A and B (3) voltages.

I have a Variac as well as I had little options for the Philco 444 being rated at 200-260 mains volts so I purchased a Variac that is 110 in and up to 240 out BUT yes you can have very low voltage and slowly crank it up (reforming Electrolytics comes to mind ;-) but even if the voltage is low, isn't the current still up there? If there is something nasty lurking under the chassis, isn't there still a possibility of destruction other than limiting the current with light bulbs or an adjustable current limited supply mentioned by Phlogiston? Another goodie about the light bulbs is if there are problems the brightness increases.

I use a variac most of the time but I also built a dim bulb tester.  I used my 3d printer to make the case, and it uses 3 bulbs that can be switched in and out.  It has another switch that can be used to bypass the bulbs, and yet another to bypass the ammeter if I am testing something that draws more than 1A.  There is a digital volt/amp meter that measure the voltage applied to the load as well as the current drawn.

Rich

Very impressive! Great work. 3D printers are so cool, someday maybe I'll get one. Which model did you make this with Criageek?

Thanks Gregg!  I bought a Prusa Mk2S in May 2017 as a kit.  It took me a weekend to assemble it but I've been printing all sorts of stuff ever since.  In fact, every single radio I've restored in that time has at least one part that was 3d printed...a couple of radios have several printed parts.  On this Fada 148 I printed knobs, dial pointer, dial lamp bracket, loop antenna frame and mount, and back cover.

[attachment=18033][attachment=18034][attachment=18035]

Rich