Need help IDing this

[mbates14]

to me, it looks like it has been recapped.

I dunno if this matters much, but I noticed in the schematic that the filters are (2)8mfd, and 1 18mfd.

well, in place of the (2)8mfd caps is an aluminum can as shown in picture, and its rated for 40mfd at 475vdc, and 30mfd at 475vdc.

the paper electrolytic is the same.

Any ideas as to why this capacitor is way different? does it matter?

[mbates14]

ok, What size fuses do I need? Im gonna stop by rat shack tomorrow and pick them up along with holders.

Im going to use 3. 1 line fuse, 1 fuse going to the filiment of the rect tube, and 1 fuse connecting the load right??

I need the fuse sizes.

1 line fuse
1 rectifier filiment fuse
1 B+ load fuse.

[Reece]

It was partially recapped, but how well, and when? That electrolytic under the chassis should be a top mount, but was cobbled in. That's a sample of how careful the recapping was. If there's a dead 'lytic up top now, you can leave it for visual effect and add new ones under the chassis. Probably need some terminal strips.

You should stick close to the values on the schematic. Too large a first electrolytic filter can overstress the rectifier tube on startup as it tries to fill up that big empty cap with juice, just what you want to avoid. You could use a 10mfd for the first cap out of the rectifier, and a 22 for the other two electrolytics. Voltages should be at least the same as the schematic or a little higher.

After checking it over and changing the 'lytics, you could probably make it play, but for peace of mind and neatness, it would be cheap to just go ahead and recap it per the schematic.

As to fuses, you can (or could not too long ago?) get little clip-in fuse holders from RS that you just solder in under the chassis. For the line you could try 1.25 amps. The heater draws 0.6 amp so a 0.75 or even 1.0 amp would be OK. The maximum B+ rating of the 6X5 is 0.75Ma, so a 100Ma (1/10 amp) fuse would work. All the fuses need to be rated for the voltage they will see, or more.

You can get even more peace of mind (how much do you want??)
by installing an NTC (Negative Temperature Coefficient) thermistor in the transformer primary circuit. This has a high resistance when cold, but the resistance drops to a negligible number quickly, allowing full power. So you get a soft-start effect for the whole set. A good one to use is a CL90, 120 ohms cold, 2 amps max. This type could be used on most radios. Resistance is only a couple of ohms when hot. Mouser and others sell them.

That'll be quite a radio when done!

Reece

[mbates14]

correction: That lytic is supposed to be under the chassis. there is no hole on top, and also in the schematics it shows it there.

the only issue is, the retainer clip is gone, so it was hot glued in.

[Reece]

Whoops...I'm at work and the pictures don't work on this computer, re: the electrolytic location. If it had been the original one under the chassis, it would have been a paper one, probably, with wire leads. The last guy just used what he had. Modern ones will be individual and a lot smaller.


Reece

[Paula]

Wow, what a neat radio! Looks like an exciting project, and best of luck with it. I have to agree with Reece -- it looks to me like that aluminum-can electrolytic that was hot-glued under the chassis is not original. That particular one appears to be 60's vintage.

In case you're interested, here's a guy that sells reproduction dial escutcheons for your radio (390X?), and also knobs and pushbuttons, though yours look fine from the picture. A tad pricy though, at twice what you paid for the radio

http://www.antiqueradioknobs.com/partlistings.html

Paula

The plastic escutcheons on prewar Philcos are notorious for shrinking and warping; the one on my 41-285 shrunk enough to pop the corners off where it was screwed onto the cabinet. Early plastics were somewhat unstable.

[mbates14]

well, mine is a little bit warped, but fotunatly, it isnt cracked at all. Thank god for that one.

[mbates14]

hey! it works! I replaced all filter caps and it works, and sounds well, great.

the speaker, umm. well.. not so great. it sounds, but thats about it. lol.

anyway, it sounds like plastic vibrating agains wood or something.

I put a filiment string fuse, and a line fuse in it, and both holds.

when the shorted lytics, the line blew, so I put a new fuse in it.

[Charlie]

Man that's great! Hopefully you'll be able to have the speaker repaired.

If you want, you could install another speaker for now to see how well the audio is. Of course, you'd need to leave the field coil leads connected on the original so it would operate. Or, if the schematic gives you a resistance value of the coil, you could just use a resistor in place of the coil. I think i had used an 1800 ohm 10 watt resistor on a radio I was working on years ago. Played fine that way while it was on the bench.

[mbates14]

I ductaped the whole speaker. *when isnt there a use for ductape*

I lost some loudness, but it sounds much much better, and it has deeper bass.

ductape is the answere to everything. its better than paper flatterin aroun when bass hits.

[mbates14]

they really knew how to make radios. damn it sounds good. it puts my damn Solid state stereo to shame. lol. it sound richer, its kinda hard to explain how it sounds. its the tubes. i love them

[mbates14]

the only problem is, I cant get it too loud without major clipping. i guess thast all 3 watts can give me.

[Charlie]

If you decide to have someone recone the speaker, just imaging the look on their faces when you present them a 60 year-old speaker with ductape filling!

[mbates14]

lol. lol.

I always ductape speakers. saves me money, and frankly, it works.