The PHILCO Phorum
Stall's 16b cathedral - Printable Version

+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Stall's 16b cathedral (/showthread.php?tid=17294)

Pages: 1 2 3 4 5 6 7 8

RE: Stall's 16b cathedral - morzh - 09-25-2017

Yes, the original dial will smear with water. Not just today's one. Actually, who knows, the repro might even not run with water.
Mineral spirits are a good wash for original dials, but trying in an inconspicuous place first is a good idea.

RE: Stall's 16b cathedral - Stall-U-Rated - 09-26-2017

"whew" Thanks for the heads up on the dialscale folks, Anyone have a favorite mineral spirit in mind that they have had great results with?

RE: Stall's 16b cathedral - morzh - 09-26-2017

Mineral spirit is a mineral spirit. I buy one in Lowe's simply because it is the closest store to me that sells it.

RE: Stall's 16b cathedral - Radioroslyn - 10-20-2017

It probably would hurt to run the tube though a tester just to get an idea what kinda shape there in. The last couple of big chassis Philco's I've serviced had several under performing tubes. Like it in 30% range. For good performance around 70% +. Replaced them with some tested good used tube and it made a big difference. Mostly the 77's and 78's.
http://www.findatube.com/

There's two electrolytic cap behind the 42 tubes.

RE: Stall's 16b cathedral - Stall-U-Rated - 10-20-2017

Thanks Terry:

That was the first thing i checked when i got this radio, Mostly measuring the 60-70% range There is a 77 which measured 56% so ill keep a lookout when its re-capped.. Looks like someone wired in a dual 8/450 e-cap at one point. Even clever enough to use cloth tape to mask the wires hehe.. Got a bit of mess-unraveling ahead of me.. Icon_smile

RE: Stall's 16b cathedral - Stall-U-Rated - 11-10-2017

Okay, was doing some tube swapping (strong test over weaker test) and noticed a few oddballs in the radio, are these proper subs the prior owner did?

A 6C6 where a 77 should be (hooked to tuner gang)

A 6D6 replacing a 78 (front of chassis)

A 41 subbed for the lone 42 tube which resides behind the 77 tube at the front of chassis..

RE: Stall's 16b cathedral - morzh - 11-10-2017

Yes all these are valid subs, should work.
The first two subs could be prone to oscillation but then might not oscillate, especially if shielded.

RE: Stall's 16b cathedral - Steve Davis - 11-10-2017

The 41 should be alright for the driver, but I wouldn't use it for either of the two outputs.

Steve

RE: Stall's 16b cathedral - Stall-U-Rated - 11-27-2017

Lets see how well i decrypted my first bakelite cap radio. How did i do?

For this radio, i will need the following caps:
11--.05 caps
1--1.0 cap
2--2.0 caps
3--.01 caps
6--.015 caps
2--.025 caps
1--.003 cap
1--.09 cap
3--10uf @450v E-caps

Please add---subtract--change whatever you feel will benefit performance... 

Thanks...... Icon_biggrin

RE: Stall's 16b cathedral - morzh - 11-28-2017

When buying electrolytics, buy high ripple current rated, at least for the cap that is directly after the rectifier.
I actually buy 20uF and then serialize them to get 10uF of double rated ripple.

RE: Stall's 16b cathedral - Radioroslyn - 11-29-2017

#75 (10uf) voltage rating is only 50v or so. Actual voltage across it is about 20v. I've read that using a cap that is many times over the operating voltage is not a great thing w/ e caps.
.09 uf isn''t a standard value go w/.1uf.

RE: Stall's 16b cathedral - morzh - 11-29-2017

#75 is not critical and can be anything, can be also of higher capacitance, can be of any ripple rating (I wouldn't go below 20mA) and of 50V WV rating. No harm here in using a cap with any voltage above.

The critical one is #87. I would not use a generic 10uF 450V here. If at all possible, use a large film cap, if not - I use Panasonic caps, there is the highest ripple rating ones at 20uF 450V, rated at about 450mA at 120HZ; I use two in series.
#88, the one after the filter choke, could be just that, 10uF 450V but I still prefer high ripple rated type, and if you use 20uF without serializing, it is still good. Though ripple here is much smaller, it still is the bulk capacitance for the whole radio, so the higher grade it is, the better.

RE: Stall's 16b cathedral - Stall-U-Rated - 11-30-2017

Fantastic information folks, THANKS!! Icon_thumbup

Speaking of #75 , this is where prior fingers have been in the radio.. #75 is missing completely (snipped out) ... An 8 @ 450v dry e-cap named "Beaver" has been soldered to the most outer contacts of #81 volt divide resistor.

#87 and #88  replaced by a single multisection 8/8mfd @475wv (screw-in type, 4 wires out) masking tape dressed for wire ties.. See pictures, page one of this topic to see the mess..

Justradios lists 2 types of safety caps, do you guys see the kind i need listed?  And Morzh, can i get the types you recommend at this site as well?

A million thanks for the input folks... Icon_smile

RE: Stall's 16b cathedral - 462ron - 11-30-2017

Mike, wouldn't putting two 5mfd caps in parallel to get 10 mfd. be better for sharing half the ripple current through each? With two 20mfd. in series, isn't the same total ripple current flowing through each instead of each taking only half the total ripple as in the first example?

Ron

RE: Stall's 16b cathedral - morzh - 11-30-2017

Ron

No. Ripple rating is the current that can be taken without exceeding a certain temperature rise.
And, as you probably know, anything connected in series sees the same current going through them. So every cap takes the same current.

Now with 5uF in parallel every cap sees half current but: a 5uF cap will likely have 1/4 current rating of 20uF cap.

Example:

EEU-EB2W220S by Panasonic.

http://www.mouser.com/ds/2/315/ABA0000C1024-947657.pdf

It has 560mA ripple @120HZ

If taking a 10uF cap, it has 310mA rating, roughly half.
There is no 5uF one in the series, and this is one of the highest-rated ones, if not the highest, but if it were, it'd probably go to roughly 1/4.

Now, paralleling two of them you achieve roughly 1/2 of the rating of the 22uF one, and serializing two 22uF ones you achieve 11uF with full current rating.