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 Post subject: Philco Model 610 restoration
PostPosted: Jul Fri 31, 2009 1:21 am 
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Joined: Jul Fri 31, 2009 1:02 am
Posts: 5
Hi all!

I just received a Philco Model 610 I'd like to restore (previously belonged to my grandparents). The radio is complete with no missing parts. I'm new to the restoration process, but I have read a few online articles to get me going. I have also found the schematic online and would like to replace all the capacitors, but I have a few questions:

1). Should I try plugging in this radio to see if it works (after it passes a dim bulb test)? All the wiring is intact, except the power cord which I will replace prior to the test.

2). Provided the radio works without replacing any of the original capacitors, should I replace them one at a time and power up the radio each time to make sure each is replaced correctly?

3). The schematic doesn't distinguish between electrolytic and non-polarized capacitors. How do I tell which is which? Is it safe to assume the larger valued capacitors are the electrolytic type?

Thanks again for your help!

Paul


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 Post subject:
PostPosted: Jul Fri 31, 2009 1:50 am 
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Joined: Jan Sun 25, 2009 12:19 am
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Location: Ohio
I'd at least pull the chassis out and check underneath before powering it up. Plus you should use a variac to do this gradually. Don't power it up with the speaker unplugged either.
It's a good idea to power up the radio every couple of capacitors you replace to avoid mistakes. I believe that radio has the bakelite condensors underneath. If you decide to "airborn" the new caps, you need to at least desolder the old ones to make sure they are not making contact with the terminals. I always take them out of the chassis and take a heat gun and clean out the old caps and install new ones. If you use the schematic on nostalgia air, your electrolytic caps will be #54 and #56 and you will probably have to use 10mfd @ 450V for those. Here is a link to the schematic I am using.
http://www.nostalgiaair.org/PagesByMode ... 013797.pdf

Another good source that may help you is link to the number code of the bakelite caps underneath the chassis. Make sure to double check this with the schematic.
http://www.philcorepairbench.com/bblokcap.htm


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 Post subject:
PostPosted: Jul Fri 31, 2009 2:43 am 
Silent Key

Joined: Jan Tue 16, 2007 11:48 pm
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Location: Hueytown, AL
I usually remove the chassis and check the B+ bus for a hard short then watch the filter caps charge up with my Simpson on highest ohms range. If it passes, then use the variac, all the while monitoring the B+ bus for voltage. You should see activity when you get to about 1/2 line volts then it should come up rapidly as you increase voltage. I do it in steps to condition the old filters. If these are leaking badly the voltage will be slow coming up. I don't use dim bulb but I suppose it would work too, maybe start with a low wattage and increase in a couple of steps.

Replace the coupling capacitor from plate of first audio amp to grid of output tube first then one at a time from there on, unless you have a block with 2 caps in it.


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 Post subject:
PostPosted: Jul Fri 31, 2009 4:58 am 
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Location: Mesa, AZ, USA
If I was totally new to this and had minimal experience, confidence and equipment, I would start by replacing/restuffing the capacitors one by one. Draw a diagram of the connections on each one before removing it, and/or take digital pictures. I would then try powering it up once done.


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 Post subject:
PostPosted: Jul Fri 31, 2009 6:02 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: ID 83301
Replace the filter capacitors then plug it in . If you dont hear any noise from the speaker within a short time then it needs to be shut off & some voltmeter testing done .

If you do decide to replace all the capacitors .. I would not do so till the radio is playing . Then after that replace 1 or 2 at a time then play it to make sure its done right .
Its real easy to make one simple mistake . If you replace 15 parts at once it will be hell finding a mistake .

Have fun


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 Post subject:
PostPosted: Jul Fri 31, 2009 1:22 pm 
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Location: Johnston,R.I.
While I somewhat agree with you Ken...about replacing 1 or 2 at a time.....I've also gone ahead and replaced all. AND... I've made mistakes, requiring troubleshooting to find. But, y'know...I think that I've learned more by those mistakes that I put into the set, than I would by anything else. Nothing quite as satisfying as finding the "mistake" or a bonafide problem with a set through good old fashioned troubleshooting!


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 Post subject:
PostPosted: Jul Fri 31, 2009 1:47 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4113
Location: Gainesville, Florida
Protecting the power transformer is a good idea. Power it-up with a dimm bulb tester that you can make with a couple simple items.
An ordinary 100W light bulb, socket with wire terminals, a single gange electrical receptacle, a piece of wire and a line cord. Wire the dimm bulb tester with the bulb in series with one side of the power so that when the radio is plugged-in to the receptacle the bulb is in series with the line between the radio and AC outlet. A brightly lit bulb would indicate a short. Although it may be bright then slowly dimm which is good. The radio would begin to play in this condition. Letting it play for short periods may reform the electrolytic capacitors in the power supply. Otherwise if the bulb stays bright then there is high current flow somewhere needing repair. Buzzing in the speaker would confirm that the power supply electrolytic capacitors need replacing.
Philco 610 is a neat model. One of my favorites

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 Post subject:
PostPosted: Jul Fri 31, 2009 3:48 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 34328
Location: Sandpoint, IDAHO 83864
For a dim bulb tester, most of us use a 25 or 40 watt bulb, not a 100 watter. A 100 watt bulb could flow nearly a full amp thru the set, which would be the same as not using a dim bulb tester anyway.
Curt

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 Post subject:
PostPosted: Jul Fri 31, 2009 4:10 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Powder Springs,Ga. USA
Plug in.
Wait 30 minutes.
Unplug.
Replace all burned or charred parts.
Restoration complete.

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 Post subject:
PostPosted: Jul Fri 31, 2009 4:25 pm 
Silent Key

Joined: Jan Tue 16, 2007 11:48 pm
Posts: 9664
Location: Hueytown, AL
Aaawwwww! you gave away my secret method :D


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 Post subject:
PostPosted: Jul Fri 31, 2009 4:43 pm 
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Joined: Mar Mon 02, 2009 11:48 pm
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Location: 97381, USA
Come on you guys. This hobby just isn't complete until you experience an electrolytic blowing up. Now that I did it my life is complete--well--maybe not until I melt a transformer :twisted:


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 Post subject:
PostPosted: Jul Fri 31, 2009 10:40 pm 
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Joined: Nov Wed 07, 2007 12:44 am
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Location: Hawthorne, Ca
I've experienced exploding electrolytics and burned up power transformers. One is a fairly expensive failure, but both will stink up your shop when the failure occurs. Harry


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 Post subject:
PostPosted: Aug Sat 01, 2009 1:00 am 
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Joined: Jul Fri 31, 2009 1:02 am
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Thanks to all who replied!

I have removed the chassis and have a few more questions:

1). It appears the set was repaired at some point in it's life. One of the 8 MFD filter capacitors has an aftermarket capacitor connected in parallel. The aftermarket one is also 8 MFD, giving a total of 16 for the two. Should I replace both with just one 10 MFD?

2). What type of capacitor should I use for the non-polarized ones and what should the working voltage be?

3). For the bakelite capacitors, would it be better to just snip the wires going to the internal capacitors and solder the new capacitors to the existing terminals? Many of these bakelites have multiple wires connected to the tabs and I feel this would be the easiest way to replace these, since I'm more concerned with getting this set running than preserving the original appearance of the chassis.

Thanks again for the help!

Paul


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 Post subject:
PostPosted: Aug Sat 01, 2009 1:11 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4113
Location: Gainesville, Florida
Actually I use a 40W bulb in my tester. But the guide that I read called for a 100W. I thought that they knew better in that article as well :shock:
Paralleled capacitors is not a good idea if a good one is over a defective one. Otherwise it adds capacitance. Follow the schematic for correct values.
Poly caps are fine for replacement. The bakelite units can have multiple components inside including capaciors and/or resistors. They are easy to remove and dig-out the contents packed in tar then replace with new components inside. The poly capacitors fit well. Keeps things neat

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 Post subject:
PostPosted: Aug Sat 01, 2009 4:41 pm 
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Joined: Jul Fri 31, 2009 1:02 am
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Hi all!

From what the last poster just stated, is it common for bakelite capacitors to have resistors inside them as well? From the link above, none of the bakelite capacitors shown on http://www.philcorepairbench.com/bblokcap.htm show internal resistors for my radio, nor do the schematic. If there is one, should I use an ohmmeter to determine the resistance?

Thanks!

Paul


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 Post subject:
PostPosted: Aug Sat 01, 2009 5:08 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 31632
Location: Livermore, CA
Hi Paul

Some Philco blocks have resistors inside. I find these resistors as a bunch of cloth covered wire. Resistance values are low.

Looking over the schematic I didn't see any resistors in your block caps.

http://www.nostalgiaair.org/PagesByMode ... 013797.pdf

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