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 Post subject: New To The Hobby: Guidance Welcome
PostPosted: Nov Thu 30, 2017 3:11 pm 
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Joined: Nov Thu 30, 2017 3:02 pm
Posts: 3
Hello, I'm new to collecting and restoring old radios. I have some basic electronic knowledge, mostly home and auto electronics. I have collected a few early GE, Philco, Westinghouse and RCA table top radios. Mostly 30's, 40's and 50's era. I would like to get them back up and running. All are complete and original sets. I am starting with the GE 603, a basic "American 5 tube radio" from what I have read.

I had the tubes tested by a friend (GE 603), and they're all good. I was planning to move on to replacing the caps next. I downloaded the schematic; learning how to read it the best I can. Starting with the electrolytic caps. I made a list of their values and voltage. My question is: "where do I buy them?" Most vendors either sold them in lots or didn't have exactly matching values.

Any books or other sources of learning would be appreciated. I plan to join a local radio club after the holidays.

Thanks in advance for the help.


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Nov Thu 30, 2017 3:32 pm 
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Joined: Jun Tue 10, 2008 6:06 pm
Posts: 454
Location: San Antonio, TX
As far as parts, you can get just about anything you'll need are available from the vendors at the right of your computer screen. Many other items are available in the "Tubes and Parts" category of this forum. Welcome and good hunting. Come back with your questions!

Dale


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Nov Thu 30, 2017 3:47 pm 
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Joined: Apr Thu 12, 2007 3:24 am
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Location: Milwaukee,WI
You can ask here first for advice. Many cap replacements do not have to be exact values. There are a couple guys in these forums that advertise selling caps. You can buy in the amount you want.


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Nov Thu 30, 2017 3:50 pm 
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Some of those odd values are difficult or expensive to match. Just replace them with the next step up.

.20 with a .22, .30 with a .33, etc. One exception where you go down would be replacing a .50 with a .47

Voltages are a minimum, if your old cap is 25 volts (for example) you can replace it with a 630 with no issue, you just don't want to go under the 25 volts.

X2 on the vendors on the right, I've been using them. Good value, nice people.


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Nov Thu 30, 2017 3:56 pm 
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Paca1960 wrote:
I downloaded the schematic; learning how to read it the best I can. Starting with the electrolytic caps. I made a list of their values and voltage. My question is: "where do I buy them?" Most vendors either sold them in lots or didn't have exactly matching values.
First, welcome to the forums.

With regard to capacitors, take a look at "Sal's Capacitor Corner" or "Just Radios" add over there >>>>>

With regard to values, often "exact" values are not really necessary. We just got into this discussion with regard to resistors over in another thread. Often with regard to electrolytic capacitors you can just pick the next higher "standard" value that is available. Let's say a circuit lists an 11 µF 400 V electrolytic capacitor. In that case a 15 µF 450 V capacitor would be just fine as a replacement.

In vintage radios, especially with regard to electrolytic capacitors, the capacitance tolerance on those when they were brand new could easily have been +/- 30% and even more (say -30% +100%). So don't be afraid of picking a value that is different by some reasonable amount. With regard to voltage rating, however, pick voltages equal to or higher for your replacement.

There is one restriction with regard to the FIRST capacitor immediately after the power supply rectifier tube. Often if you will look up the data for the tube you will see a specification for the maximum capacitance allowed for that one. So it is unwise to exceed that value. For example, with a 5Y3 rectifier tube ( https://frank.pocnet.net/sheets/127/5/5Y3GT.pdf ) the maximum value recommended for the filter "Input Capacitor" is 20 µF.

One other restriction on capacitors is the value for any capacitor that is involved in a "tuned circuit". Tuned circuits are those that use a capacitor with an inductor to "resonate" at a certain frequency. In those cases you really try to get the identical values. These are typically the small value Mica capacitors that you seldom have to replace anyway (not generally a failure issue) so this is not a problem that is encountered often. For these we are typically talking values in the 10 to 1000 pF range and you can often get exactly what you want if you need one.

Best of luck.

Curtis Eickerman

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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Nov Thu 30, 2017 10:56 pm 
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Welcome! You've come to the right place.
Get yourself an isolation transformer before working on those AA5's...plenty of threads here on that subject and why it matters.
It's worth the $$.
cheers

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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Fri 01, 2017 12:08 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: S. Dartmouth MA 02748-1225 USA
Welcome....

What do you have for test instruments?

There is a tutorial stored on this site which is a great help for new comers to the hobby:

http://antiqueradios.com/archive.shtml

Elements of Radio Servicing, download all chapters.


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Fri 01, 2017 6:42 pm 
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Location: McPherson, Kansas
I'm glad to see "new blood" in this group. Best wishes for success in your new hobby :)


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Fri 01, 2017 7:06 pm 
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Joined: Sep Tue 30, 2014 6:08 am
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Location: The Old Dominion VA 23518
Sources for parts:

viewtopic.php?f=19&t=201537

Tom keeps this up well - no dead sites...

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Brian
"Capacitor Cosmetologist since 1979"
USN Retired 1984-2006 (Avionics/Cal)


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Sat 02, 2017 1:17 am 
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First - make a dim-bulb tester and always use it for the first power up of a new old radio. Serious damage can happen if the power supply electrolytic capacitors are shot. The dim-bulb tester will prevent damage.
Second - If the radio more or less works, replace only one cap at a time and test after each change. That way, if you make a mistake, it is much easier to solve the problem.
Last and most important - Welcome! This is a really neat hobby


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Sun 03, 2017 3:13 am 
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Joined: Nov Thu 30, 2017 3:02 pm
Posts: 3
Thanks for everyone's comments and encouragement. Onward with the learning and my first restoration project.

I took photos of the GE 603 chassis and started a list of Caps to replace. First up, I'm not sure about this one:

Dual Dandee Electrolytic, Type PRSA, DCWV 150, 50 - 50 MFD. Has two wires coming off the top and one off the bottom of a large cardboard cylinder.

So, is this two Caps in one? Sorry, I'm confused on this one and not versed on reading the schematic much.

What should I replace this one with?

Thanks!


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Sun 03, 2017 3:22 am 
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Yes, it's a two in one. Replace it with two 47mf, 150 (or more) volts capacitors.


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Sun 03, 2017 6:41 am 
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Location: Maryland 20709, USA
tomgrigsby wrote:
Serious damage can happen if the power supply electrolytic capacitors are shot.
Hi Paca,

Important safety note...

NEVER apply power to a set until the original electrolytics have been replaced.
Doing so can damage other parts, including some that may be expensive or impossible to get.

BTW... Welcome Aboard.

- Leigh

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http://www.AtwaterKent.info
Click "Grebe Stuff" for Synchrophase info


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Sun 03, 2017 7:04 am 
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Joined: Sep Mon 18, 2017 2:23 am
Posts: 120
Location: Plymouth, MI
Hi Paca,
I'm fairly new to restoring antique radios and this forum. What I've discovered here are a lot of great people who have vast experience and are gladly willing to share it with us newbies.
So go ahead and ask any question you have, someone, and usually many, will have the answer you are looking for.
Welcome to the Forum!

Dan


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Sun 03, 2017 7:26 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3966
Location: Charleston, W.Va.
Hi Paca and welcome to the antique radio forum!

In addition to the advice you have already received here, I would recommend you check out the following website:
https://antiqueradio.org/begin.htm

The above section of "Phil's Old Radios" has some excellent information useful to all antique radio beginners, and will answer a great many of your initial questions.

Good luck, and don't hesitate to ask for specific advice here in the forum.

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Poston


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Sun 03, 2017 9:02 pm 
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Joined: Sep Wed 23, 2009 8:46 pm
Posts: 73
Location: Moscow area, Russia
My method.
In our country, it is very difficult to get a working imported electrolytic capacitor in the first half of the 20th century.
I do the following:
- cut the capacitor body around the circumference
- I remove the filling
- I place inside the case of the original capacitor a modern electrolytic capacitor
- the positive terminal of the capacitor is soldered to the central terminal
- I output the negative terminal of the capacitor through the hole drilled in the aluminum case and solder to the ring which is placed under the nut of the original capacitor.
- Restore the appearance of the condenser with a shrink tube
Here is a photo of my receiver Graetz. I did not have a transparent heat-shrinkable tube at that time :) .
Image Image

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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Mon 04, 2017 12:19 am 
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Posts: 3500
Location: McPherson, Kansas
Dual Dandee Electrolytic, Type PRSA, DCWV 150, 50 - 50 MFD. Has two wires coming off the top and one off the bottom of a large cardboard cylinder.
***************
One "off the bottom" is probably black and a "negative." Twist your two new capacitor negatives together when you rewire.
The other two wires on the top are commonly blue & red--but not always. Since the original had two 50 mfds, you don't have to worry about which you replace where. If they were not both 50's, you'd have to know which is which.

Clear as mud?


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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Mon 04, 2017 3:25 pm 
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Joined: Nov Thu 30, 2017 3:02 pm
Posts: 3
Art / Everyone - thanks again for the continued advice. I'm ready to order Caps and get to work.

Taking pictures, will build a Dim Build Tester, order new Caps and get to work. I'll start posting some pics.

Thanks again guys!

Jim


Last edited by Paca1960 on Dec Mon 04, 2017 4:28 pm, edited 1 time in total.

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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Mon 04, 2017 3:45 pm 
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Paca1960 wrote:
Should I replace those wax Caps, look like they are wrapped in paper? Guessing "yes", and if so what new style Cap would replace these?
The short answer is yes, and non-polarized axial film type capacitors (they are the yellow capacitors you see all the time).

Some people use the radial lead "Orange Drop" style of replacement capacitors. They are fine. They take up a little more room and are perhaps not quite as convenient to install as replacements for the vintage axial leaded parts.

The slightly longer answer is that the insulation in the original capacitors is actually paper (hence, you often see these referred to as wax/paper, paper/wax or just paper capacitors). The insulating paper used in the capacitor deteriorates over time and eventually loses its ability to insulate the plates of the capacitor from one another. The result is that a resistive path develops which allows current "leakage" through the capacitor (never a good thing). In the worst cases the capacitor becomes completely short circuited leading to damage of other parts. Paper/wax capacitors, even if they presently measure OK, are little time bombs in the radio. If you are lucky, when they short circuit, they only cause a burned out resistor. If you are not so lucky they can cause a destroyed speaker field coil, audio output transformer, or IF transformer which are all significantly hard or expensive to find/replace.

There are also Mica capacitors that are generally not a problem (Mica insulators hold up with age pretty well). Mica capacitors are often left alone unless they are proven to be a problem as a result of troubleshooting for some type of failure. Mica capacitors in vintage radios tend to look kind of like small dominoes. Their values are often in the 10 pF to 1000 pF range.

Curtis Eickerman

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 Post subject: Re: New To The Hobby: Guidance Welcome
PostPosted: Dec Tue 05, 2017 4:33 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3966
Location: Charleston, W.Va.
Paca1960 wrote:
Thanks again guys!
Jim

Hi Jim,
I appears that you are on the right track. As you have already learned, there is a lot of help and useful advice available here on the ARF. But in particular I note that Curtis Eickerman has made a couple of posts to your thread, which is fortunate for you. Pay attention to him! :!: Many of us here have technical skills and knowledge, but in addition to these Curtis has a lot of teaching experience. He has a unique way of combining his knowledge with his teaching skills, and usually expresses himself in such a way that even a complete novice can easily understand and learn from him. Curtis is a big asset to our forum. :)

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