Philco model 18 (code 121) - HELP! - Printable Version
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+--- Thread: Philco model 18 (code 121) - HELP! (/showthread.php?tid=5934)
RE: Philco model 18 (code 121) - HELP! - BrendaAnnD - 04-25-2013
I don't know about the others, but I can't get a mental picture of that coil by your description. Could you post a pic of it?
You won't necessarily SEE a break in the coil. It could well be corroded through at a point where it looks to the naked eye like it's still intact.
6 lugs? I would also think that coil would only have 4 lugs for the two coils that it has...
RE: Philco model 18 (code 121) - HELP! - jerryhawthorne - 04-25-2013
Tough to relate to pants and underwear.
Let's make it simple Pith. Brenda, there should be six lugs on that coil. Two for the primary and 4 for the secondary which has two taps for band changing. Pith, your correct, two of those lugs should have two wires from the coil going to them, these are the taps from the secondary. Put your meter probe on either one of these and set your meter on the low resistance scale. Now measure to the other double wire lug should be low. Now leaving your meter connected to the first point, move your probe again to the lug going to the cap of the oscillator tube. Should read low. Now check the remaining lugs and you should find one more lug reading low. This will confirm the secondary of your transformer is good, you have continuity across all four of the connections.Now, if you remembered which two had no connection to any of the four you just identified, these would represent the primary of your transformer. One should have gone to the plate of your RF amp, the other will go to C12 and on to more connections. Those two should show continuity but according to previous measurements didn't. Try measuring between these two to make certain there is no continuity and the coil is "open" (broken).
If still open, hopefully someone can answer your question of wire size and perhaps number of turns.
I have to go and change my pants.
Good luck, Jerry
RE: Philco model 18 (code 121) - HELP! - Pithicus999 - 04-25-2013
Ha, Jerry, hopefully you made it in time?
"I put my pants on one leg at a time...just like everyone else. The only difference is that once my pants are on, I make Gold records!" (SNL - Christopher Walken cowbell skit. I really wanted to post the youtube video but I couldn't find one that didn't suck or have extra stuff added.)
Remeasured R.F. (P-K) #78 tube just for the heck of it since I still had the coil hooked (but not re-soldered) in the chassis. Measured
1.8 volts.
Bypass of secondary coil I 'jumped' from R.F. plate to #12 cap and measured 270 volts on the I.F. and 270 volts on the R.F. (P-K) #78 tubes. [I've never done this before. Just had physics in high school and college. Never soldered anything, or used a multimeter so this is actually exciting as dumb as that sounds. I just walked past this radio in my parents basement for so many years-I'm 37 now--I realized if I didn't pick it the D**n thing up and take it home it would never work again!] Anyways, I can tell from that bypass and the schematic that the 'underwear' or Primary coil is open, and now understand what you mean. I'll still do the measurements you've outlined.
Ok, 'loop' to 'loop' are measuring .004 Ohms like you said Jerry.
'Red-Blk-Green' resistor tab is measuring .004 Ohms...so far so good.
The two tabs of the Primary or 'underwear' tabs (the Plate tab and the #12 Cap) are off the charts on Ohms, so you know what that means don't you?
It means that I need to go change my underwear.
RE: Philco model 18 (code 121) - HELP! - jerryhawthorne - 04-26-2013
Just to confirm, good measurements on loop to loop and loop to one other lug (with resistor) that takes care of three of the lugs, should have one more (the one going to the grid cap) with low resistance as well, for a total of 4 lugs all measuring low to one another. If that's the case, you just need to rewind your underwear.
Jerry
RE: Philco model 18 (code 121) - HELP! - Pithicus999 - 04-26-2013
!!!!!!IT'S ALIVE!!!!!!!
Well, rewinding that coil may have been the hardest thing so far. I had to do it 3 times, luckily there were only 18 winds. I tried to make it perfectly smooth (like the one I removed) but found out that the wax or whatever it is that was covering it made lots of small bumps and so the re-wind isn't as smooth. It's working though! Have it on right now. Only get's one station, but I'm hoping that's because I need to tune the thing again, and this time with a sig gen that actually works.
I'll try and post some pics tomorrow. Now need some sleep! Thanks for the help. I'm sure I'll Q's about tuning. Today is actually my dad's birthday, which is pretty awesome to think that this thing is working now. Thanks again.
Stay tuned for pics!
RE: Philco model 18 (code 121) - HELP! - Pithicus999 - 04-26-2013
Hey Jerry, forgot to answer your question. Yes, the 4 lugs measured low, and the 2 on the primary measured high or infinite I guess you could say.
gonna post a video on youtube and give you the link. I had radio on this morning for about an hour. Started off fine, with good volume, then it got really quiet. When you touch either of the #78 tubes it gets louder. Wonder if thes amplyfiers aren't doing their job? Or if there is something else i'm missing?
Suggestions? Maybe suggestions after you see the video?
RE: Philco model 18 (code 121) - HELP! - jerryhawthorne - 04-26-2013
Jerry
RE: Philco model 18 (code 121) - HELP! - Pithicus999 - 04-29-2013
Still need to upload video, busy weekend. Anyone know how to make an antenna for this radio? Got a strong station while in Ann Arbor but one I drove 30 miles to my dads house I couldn't get a station. Thought it might be the antenna? All I have is a thin wire about 2 feet long.
RE: Philco model 18 (code 121) - HELP! - Walston - 04-29-2013
This thread is quite interesting. Congrats on getting your Dad's radio working. I am sure once you get it tuned it will receive better. I have just started on a Philco 37-60, it was my Grandfathers, first time I worked on one this old.
RE: Philco model 18 (code 121) - HELP! - BrendaAnnD - 04-29-2013
Pithicus,
These radios are designed to work with longwire antennas. You should use at least 20' of wire, and will obtain best performance with a wire of 50' or longer, strung outdoors. Many places this is not possible, so use as long a wire as possible, strung around the eaves of the house, or across the roof, etc.
RE: Philco model 18 (code 121) - HELP! - morzh - 04-29-2013
My Philco 18 works with a fairly short piece of wire. WIll it work better with a longer one? Possibly. But at this point I am quite OK with a couple of meters of it. And for the local station it needs no wire at all.
But of course if you have the space for a long aerial - could only make things better. Will possibly draw few lightning, but it's a small price to pay for good reception.
RE: Philco model 18 (code 121) - HELP! - jerryhawthorne - 04-29-2013
Pith, have you done a full alignment on the radio yet? Longer wire is better. Thin wire is just fine.
Jerry
RE: Philco model 18 (code 121) - HELP! - Pithicus999 - 04-30-2013
Thanks everyone for the help and ideas! What I found online, and what I remember from when I was a kid was to use a 'loop' of thin wire about the width of a bowling ball and hook up the two ends one to the GND and the other to the ANT at the back of the chassis, and then just tape the wire antenna to the inside back of the cabinet. Would that work any better? It looks like the bigger the better due to the length of the wavelength which is pretty long. I want to use what will give the strongest signal I guess.
Jerry - This coming weekend I'm going over my parents to check all the voltages and I'll post any results that don't match what they should be. About the Sig Gen, while I was tuning the radio, I did what you said and had the multi-meter hooked up to the voice coil and could see the meter moving as the person's voice on the station got louder. But sometimes, the multi-meter didn’t move at all when I was turning the tuning nuts/screws?? So, I decided that I would check to see if iPhone made a decibel app and they do, so I got that on my phone and put it by the speaker to watch how loud the speaker was getting (I could hear it, but it was so minimal it was hard to tell an increase or decrease in decibels). Anyway, following the schematics, through all 7 adjustments, I used this same method of watching the app to its highest decibels on this one station. The result was that when I was in Ann Arbor, 1 channel was coming in great (at this point I had only the antenna wire from the 'Coil' to the ANT clip on the chassis, I didn’t have the 2 feet of wire that was added when I got to my dad’s place).
My thought or fear is that in the event that the signal generator isn’t working properly, just because I was able to tune the radio to one station (via listening), doesn’t mean that the radio is “Properly Tuned” across ALL stations right? Because each station corresponds to a different frequency and tuning is based off of kilocycles from the sig generator to mimic those stations and make the tuner sensitive to receive those stations…
RE: Philco model 18 (code 121) - HELP! - Pithicus999 - 04-30-2013
...I think I'm learning
It's funny that over the weekend (because I'm not normally an ‘electrics’ kind of person, but I do other more home improvement type stuff) my sisters were calling me McGyver when they saw the radio. Do I take that as a complement? As far as I know there was no duct tape used in this radio and I’m hoping that it wasn’t a ‘hack job’.
Also Jerry, the next time I’m in Sedona (which could be this fall) I’m buying you a beer! I’m pretty sure that I owe you a few. As well as others who have helped me along the way, Brenda most recently. Beers all around!
RE: Philco model 18 (code 121) - HELP! - jerryhawthorne - 04-30-2013
Pith, radios like this do not like a "closed" loop antenna, they want a "long wire" connected to the antenna terminal. Ground is somewhat optional.
When you are doing an alignment you should be listening to the tone from your signal generator (constant), not listening to radio programming that has a variable volume level! Much easier to peak the various adjustments. Start @ 260KC for IF then follow directions to peak the high and low ends of the band using your signal generator with modulation at the appropriate frequencies, not a radio station.
Jerry