[eewill]

Yep. That’s what I saw. I didn’t know if it was being used for better noise filtering or something along those lines.

[morzh]

It does not matter.

Somewhere in a switcher power supply, the output capacitors are often divided in two while using low ESR type; the two in parallel cut the ESR in two and thus cut the ripple voltage, also in two. Though a higher capacitance part from the same family might have lower ESR, but not necessarily half.

Here...it matters very little if at all, plus the film caps are failry good anyway.

[RodB]

Providing the 0.3 physically fits.

[morzh]

Should.
Also, these days there are axial flat caps.
I have them in 0.47uF.

The cap 0.33uF 630V axial film flat.
https://www.mouser.com/ProductDetail/Kno...2FhA%3D%3D

the datasheet showing the shape
https://www.cde.com/resources/catalogs/MMP.pdf

[eewill]

Thanks again guys. I'm making slow progress. The case has been refinished and I've cleaned up the chassis. I'm starting on the cap replacement when I can find time. I'm keeping my fingers crossed that something else doesn't need to be fixed.

I will say one thing. These wire wrapped solder joints are a pain to unsolder.

Just curious, if one of the transforms in the cans needs replacing, what's the options there?

[morzh]

Find a junker chassis...once in a while people part radios on eBay.

[Arran]

Or post an ad in the buy and sell section, or ask on this thread. Quite often you can repair them, such as with a grid cap lead.
Regards
Arran

[DaleHCook]

I will say one thing. These wire wrapped solder joints are a pain to unsolder.

My approach is to use two tools at once - a soldering iron to provide the extra heat often needed for that mass, plus a vacuum desoldering station to remove the solder. Once the solder has been removed it is easier to unwrap the wire.

[morzh]

I leave a stub after cutting the part being replaced. I use thin needlenose pliers to pull while heating. Usually the direction of wrap becomes obvious during this procedure. Sometimes it is not easy, agreed.

If this is a coil/RF transformer, I do not unwrap: too strong a possibility of a damage.

[eewill]

Just confirming. The two 8uF capacitors in can #67 have negative sides tied together and connected to the side that is tied to the center tap of the secondary winding on the power transformer.


Also, I have a capacitor that seems to have been added and is not on the schematic. It's definitely a modification and not original. It is the only thing that has been directly soldered to the chassis. It connects from the power/volume switch side of #43 to ground. I've removed it and don't have a plan to put it back. Not sure what it would have been added for. You can see it in my original photo showing the underside of the chassis. It's a yellow 0.001uF capacitor in the upper right of the pho

[morzh]

eewill

Yes, both 67 have their Minus on tthe centertap.

Also (important!!!) if you ever see a cap that is connected same as #68 (some Philcos have it) and IS electrolytic, the GND receives the Plus. And the Centertap - minus.

[eewill]

morzh,

Don't have that one. Yeah. I'm still struggling to understand voltage levels at various locations on here. I suspected that some of these might be backward from what I initially thought they would be. That's why I verified the direction of the #67 electrolytics.

Forgot one capacitor from my order over at JustRadios. Accidently ordered a single capacitor from there without noticing the $30 minimum and had it refunded to me. (Oops) Had to go through DigiKey to order a single capcitor. Waiting on that one to come in before I can finish installing caps. All of the other capacitors have been changed except the bakelite #69.

Will be reading back through this thread and others about first time powering up soon.

[morzh]

Polarity is easy to remember: The centertap is the MOST NEGATIVE point (the rectifier's minus) in the whole of the radio and therefore any cap taht is connected to the centertap will have its Minus on it.

[eewill]

Success! So far at least. All capacitors have been replaced and I've successfully powered up the radio. Used a variac initially but didn't have any issues. Other than the volume control and tuner (which are obvious) I'm not sure what the positions on the other knobs are. I do know that I get a terrible squealing tone for most settings. I think that might be due to the fact that I don't have the tube shields on. I left them off in case I needed to remove and test.

Some of the wires that connect to the top of tubes have cracked and exposed the conductor. I'm going to search for something to coat them with instead of replacing the wires completely.



@morzh What's the mod to add an aux input to the radio? That might be something I'm interested in.

[eewill]

I did mean variac. Made the correction.