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Philco 84 Electrolytic - Printable Version

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Philco 84 Electrolytic - Ralph - 12-01-2022

Hi, I just opened up this radio and have what is probably a simple explanation. 
There are 3 tabs on for the 30-2013 electrolytic on the Philco 84 that consists of  a 4 and a 8 mfd in it. The electrolytic has one of the tabs marked green the next one is red and the 3rd on is unmarked. I am planning on using 2-10 mfd electrolytics to replace them but not sure hoe to wire it.
Ralph

RE: Philco 84 Electrolytic - Radioroslyn - 12-01-2022

Two 10mfd @ 450vdc is fine. The + connections go to the terminals in the middle of the can and the - goes to the single tab on the side. Be sure to use the cardboard insulator, it's not at chassis ground but at b-.

GL

RE: Philco 84 Electrolytic - Ralph - 12-01-2022

Im still a little confused. You can see the 3 tabs on the old electrolytic. If you look close you can see the red and green tabs

RE: Philco 84 Electrolytic - morzh - 12-01-2022

I think the wire that goes to the wirewoumd and the cap in parallel on the left (the leftmost terminal of the cap) is the common negative for the other two terminals (red and green wires) that are 8 and 4 uF caps respectively.

So follow Terry's advice.

The type of the cap:: COMMON NEGATIVE-CASE UNGROUNDED, 30-2013 . . . . . . . . . 1.60

http://philcoradio.com/library/download/parts/catalogs/1939/Philco%20Parts%20Catalog%201939.pdf

RE: Philco 84 Electrolytic - Ralph - 12-02-2022

Hi Terry & Morzh

Is this how I am to wire it?

Thanks

RE: Philco 84 Electrolytic - Radioroslyn - 12-02-2022

Yup you got it. The - side goes to the 325 ohm wire wound resistor/high voltage center tap. The +'s go to the 16K and the filament of the 80 tube. Don't know if you are a diagram reader, the filter caps +'s are on the top and -'s are bottom.

Sorry to confuse. A lot of the Philco e caps a metal tab that slips in between the can and the cardboard insulator. This is where the - connection is made. Yours is a little different. Not wrong as I looked at one of my 84 and it looks just like yours. My mistake.

https://philcoradio.com/library/download/service%20info/service%20bulletins/Philco%20Service%20Bulletin%20178.pdf

GL

RE: Philco 84 Electrolytic - radiorich - 12-02-2022

hello Ralph,
You, are getting the hang of it So have you done the bakelite blocks yet ?

Sincerely Richard

RE: Philco 84 Electrolytic - Ralph - 12-02-2022

Hi Richard,
Yes I have done Bakelites the easy way by drilling out the connections of the old caps and just soldering new caps on top. This time I was thinking about emptying them and repacking them.
Ralph

RE: Philco 84 Electrolytic - radiorich - 12-03-2022

Hello Ralph,
Yes I like doing the re-stuffing of the bakelite blocks and on my coming up project my Philco 38-10 I will be doing that .
Far as your set goes I think it deserves to have that done since your chassis is a really clean and neat chassis !

Sincerely Richard

RE: Philco 84 Electrolytic - Ralph - 12-18-2022

Well after I wired the electrolytics, I did not have HV on the plate of the output #42 It took me a while to find that problem. The rectifier socket was still dirty and the socket was not holding the #80 tight enough..........

So now I get screeching, motor boating and scratchy noise when I put my finger on the 1st detector tube #77. If I put my finger on the grid cap and steady pressure on the chassis I get a clean tone. Is that a ground problem somewhere?

Thanks Ralph

462ron - 462ron - 12-18-2022

Hi Ralph, did you do an alignment yet on your set following the directions on the schematic that Terry linked to on post #6 above. Your set is a regenerative model and will make squealing noises if adjustment #17 aren’t set right.

Ron

RE: Philco 84 Electrolytic - Radioroslyn - 12-18-2022

As Ron mentioned you can unscrew #17 a couple of turns and see if that calms things down. Also there's a rivet on the 2nd 77 socket that grounds the cathode & surpresser grid thru a small metal strap. This rivet connection gets oxidized over the yrs and can cause hum and squeals. You could replace the rivet but it's in a tight place and it's a pitb. So what I've done is remove the IF adjustment trimmer above it and fit it with a ground lug. Cleaning the contact surfaces to insure a good ground along the way. Solder a piece of wire from the lug to one of the pins the metal strap is connected to. Job done. There's also a strap over on the 42 between pins 5 & 6 (cathode/ heater). If this rivet is a bad player it can cause hum. Just the run a wire between the two tubes to ground.

Once you get it to settle down hook your generator up and send a 460kc signal to IF. The osc doesn't have to be working to align the IF, it does to mix the pickup stations. It's important that it's on the nose at 460kc for good sensitivity and selectivity else the the performance is going to be poor... Good high emission 77's help a lot too.

GL

RE: Philco 84 Electrolytic - Ralph - 12-19-2022

Im still not having any luck. I have added a ground lug and added wires to the ground of #77 and#42 when I did try to align it it had a good strong tone no matter how I adjusted all 3 trimmers also still don't get any stations. Could it be a bypass capacitor problem? Any help on this is appreciated.

Thanks, Ralph

RE: Philco 84 Electrolytic - RodB - 12-19-2022

I'm confused as to understanding if you are still having trouble with the electrolytic wiring or receiving broadcast stations. If voltages are good and IF signal is getting through then the place to look is the oscillator. Don't assume that mica caps are good.

RE: Philco 84 Electrolytic - Ralph - 12-19-2022

Sorry for the confusion: After I sent my last message I realized by mistake I hooked the signal generator up on the wrong#77
After I corrected that I was able to faintly get a radio station. The generator tone was low at 460kc.
Im going to get back to it tomorrow and do more with the alignment.