battery pack for Philco 39-85 121
Posts: 3
Threads: 1
Joined: Jul 2012
City: Minnesota
I am new to the forum and radio restoration in general.
I have a Philco 39-85 121 that requires the A-B battery pack.
It still has the 4 prong connector.
I built an A battery pack out of 6 D-cells wired in parallel.
I may have somehow messed this up because the pack voltage read 3V.
The A pack was connected to the two prongs that were closest together.
The B pack I built out of 10 9V batteries wired in series. Their combined voltage read 89V.
The B pack was connected to the two prongs that were farther apart.
The tubes powered up yesterday, but there was no sound coming from the speaker. I checked the speaker and it is good.
Anyone have any suggestions? Did I possibly connect the packs incorrectly?
I tried to power up the radio today, but the tubes would not power up.
Any advice would be helpful. Thanks.
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City: Merrick, Long Island, NY
Slow down, batteries may be the least of your problem. Plenty of stuff on making 90 VDC qnd 1.5 VDC supplies. Beware that ancient wax capacitors can and almost are always leaky, and resistors are many times way out of tolerence, usualy high. It is rare in my humble opinion to find portable tube filaments blown without probable cause easily detectable with nose and eyes. Here is the closest I have access to:
http://www.nostalgiaair.org/PagesByModel...013312.pdf
(This post was last modified: 07-28-2012, 07:14 PM by codefox1.)
Posts: 336
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City: Montreal, Qc
I agree with codefox. It is a bad idea to power up old electronics without looking at the insides.
The first tube radio that I got had been mickey mouse's party penthouse several years back; its sometimes surprising.
The old capacitors are likely not as good as they were 70 years ago. Some might be completely broken. I am uncertain for that specific model, but the wiring of some Philco from that era has become brittle and might need to be changed.
Your specific radio isn't that complex, you might want to look at it, change the capacitors first. Just today I heard sound from a battery-operated radio that wasn't working prior to my changing 8 capacitors and making a battery pack similar to yours.
Hope you like your radio.
Once you make it working, you'll be happy to have made the time investment into it.!!
-Mars
Posts: 1,562
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Joined: Nov 2008
City: Sedona, AZ/Placentia/CA
Tank, I certainly agree with the above comments on replacing caps and checking resistors. However I am concerned about your comment of your A pack of batteries giving 3V. Being twice as high as it should be, those tubes would not last long. You really need to check how those batteries are wired together. They don't "glow" much, in fact hard to see them glow without turning out the lights. If you saw them glowing, probably running too high on the filament voltage. Check the A pack and then check the tube filaments by removing one at a time and using an ohm meter check each for very low resistance. Let us hope, you have not taken out all of the filaments in the tubes. Must get that voltage down to about 1.5V. Report back on your findings and good luck on your first radio. Always memorable and will lead to working on even more.
Jerry
A friend in need is a pest! Bill Slee ca 1970.
Posts: 3
Threads: 1
Joined: Jul 2012
City: Minnesota
Thank you all for the advice. I figured out what was wrong with my A battery pack. Very stupid mistake; I accidently had two of the batteries in series. Wiring under chassis is good, no shorts or corrosion. Resistors seem to check out. Will be checking resistances on all tubes next. Did have one tube that must have been broken when I bought it.. With luck I will just have to replace a General Electric tube marked 8-48 118-5. The connector on top of the tube was loose enough that it had fallen off. Any suggestions as to where I could purchase a replacement tube?
Thanks again.
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City: Sedona, AZ/Placentia/CA
Tank, if your speaking of the grid cap on top of the tube, they are often easily saved if you have a little bit of the wire coming through the top of the tube left. If you do, clean it well and select some small diameter solid wire and tin it and turn a tight loop around a jewelers screwdriver. Slip over the piece coming out of the tube. A little solder flux on the assembly and a touch with your soldering iron and a little solder and you should have a solid connection. Drill a small hole in the top of cap. large enough to feed the wire through.
A dab of crazy glue on the rim of the tube cap and slide the cap down the wire and let it set up on the glass top of the tube.
After drying, a dab of flux on the extended wire and cap and again, a quick touch of the soldering iron to the cap and wire. Quick as you don't want to melt the solder holding the wire in place on the tube.
Your done!
Good luck Jerry
PS: You might wish to check the filament of the tube prior to this.
A friend in need is a pest! Bill Slee ca 1970.
(This post was last modified: 08-01-2012, 03:23 PM by jerryhawthorne.)
Posts: 3
Threads: 1
Joined: Jul 2012
City: Minnesota
Thanks! There was a 2-3 mm piece of wire here but when I tried to bend it up slightly off of the glass, it broke off flush with the tube. Im not sure if I could s older it safely at this point. I also looked at the wrong number on the tube, it was a 1H5G. Slowly learning but I think Ill get there. The rest of the tube looks fantastic.
Posts: 1,562
Threads: 56
Joined: Nov 2008
City: Sedona, AZ/Placentia/CA
Tank, give us a report on your tube filament situation. Do they all look good on your meter? Even flush with the tube, you may be able to get a connection. No need to try if the filament is open.
You can post here in the for sale forum for tubes if you need them. Good prices and reliable people.
Jerry
A friend in need is a pest! Bill Slee ca 1970.
Posts: 104
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Joined: Oct 2005
City: Indianapolis, IN
I made a cover for the A battery, kind of an odd shaped affair. I can send the patterns if you'd like.
Bill
\
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Joined: May 2007
City: Raleigh, NC
I'd love to see the patterns!
John Honeycutt
Posts: 1,562
Threads: 56
Joined: Nov 2008
City: Sedona, AZ/Placentia/CA
I hate it when a thread seems to die. Wonder how things are going on his nice set. Did you just give up?
Jerry
A friend in need is a pest! Bill Slee ca 1970.
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