Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
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.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 165
Threads: 5
Joined: Jul 2017
City: Woodland, CA.
"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?
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
Mineral spirit is a mineral spirit. I buy one in Lowe's simply because it is the closest store to me that sells it.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 7,248
Threads: 266
Joined: Dec 2009
City: Roslyn Pa
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.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 165
Threads: 5
Joined: Jul 2017
City: Woodland, CA.
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..
Posts: 165
Threads: 5
Joined: Jul 2017
City: Woodland, CA.
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..
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
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.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 1,400
Threads: 70
Joined: Oct 2007
City: Linn Creek, MO
The 41 should be alright for the driver, but I wouldn't use it for either of the two outputs.
Steve
M R Radios C M Tubes
Posts: 165
Threads: 5
Joined: Jul 2017
City: Woodland, CA.
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......
(This post was last modified: 11-27-2017, 05:57 PM by Stall-U-Rated.)
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
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.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 7,248
Threads: 266
Joined: Dec 2009
City: Roslyn Pa
#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.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
#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.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 165
Threads: 5
Joined: Jul 2017
City: Woodland, CA.
Fantastic information folks, THANKS!!
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...
Posts: 778
Threads: 48
Joined: Feb 2013
City: Shenandoah,
State, Province, Country: Pennsylvania
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
Bendix 0626. RCA 8BX5. RCA T64
Philco 41-250. Philco49-500
GE 201. Philco 39-25
Motorola 61X13. Philco 46-42 Crosley 52TQ
Philco 37-116. Philco 70
AK 35 Philco 46-350
Philco 620B. Zenith Transoceanic B-600
Philco 60B. Majestic 50
Philco 52-944. AK 84
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
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.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Users browsing this thread: 2 Guest(s)
|
Recent Posts
|
Cannot Adjust an IF Transformer’s cores
|
Outstanding work indeed. I wish I could come up with solutions like this.slford310 — 11:16 PM |
Cannot Adjust an IF Transformer’s cores
|
The abilities of our 'Phorum Pholks" never ceases to amaze me! Fantastic fabrication, Joseph! I'm waiting now for...GarySP — 08:27 PM |
PT-6 antenna connections
|
Thanks. I never realized that was a notch noted in the schematic as described. I’ll recheck my wiring.bridkarl — 08:13 PM |
Cannot Adjust an IF Transformer’s cores
|
Thank you! I was quite new to the Phorum when I started this post, so I feel like it might be advantageous to publish a ...jrblasde — 08:07 PM |
PT-6 antenna connections
|
Notice in the schematic the notch at the bottom of the antenna coil is between pins 3 & 4.
Yes, pin 6 of the 7C6 is...RodB — 07:34 PM |
bridkarl
|
I have two PT-6 chassis. On both there is a blue wire that runs from the above chassis transformer to pin 6 of 7C6. So t...bridkarl — 07:23 PM |
Cannot Adjust an IF Transformer’s cores
|
Joseph, now you are an engineer!!RodB — 06:37 PM |
PT-6 antenna connections
|
Hi, reading your explanation I can see the confusion. If you take it one connection at a time it should result in a desi...RodB — 06:34 PM |
Cannot Adjust an IF Transformer’s cores
|
It works! I received the PCBs this morning in the mail, and put everything together. I reused the base from the original...jrblasde — 04:32 PM |
PT-6 antenna connections
|
I seem to have lost my way on this PT-6.
I see the antenna aerial transformer schematic - I’m reading pins 1 through ...bridkarl — 12:30 PM |
Who's Online
|
There are currently no members online. |
|
![>](https://philcoradio.com/phorum/images/bootbb/asb/right_arrow.png)
|