Philco 42-1002P parts values question - Printable Version
+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Philco 42-1002P parts values question (/showthread.php?tid=15720)
+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Philco 42-1002P parts values question (/showthread.php?tid=15720)
Philco 42-1002P parts values question - ccomer1955 - 11-20-2016
The candohm is measuring at 50 ohms which is what the schematic calls for, but I've always heard that it is best to replace them while you're working in the chassis since they will go out sooner or later. Would a 5w 50 ohm sand resistor do?
Also, on the 40-40 electrolytics, will 250 volt caps be sufficient?
I've been replacing rubber coated wire, resistors, and wax caps today, but tomorrow I will head over to the electronics shop after work for the rest of the parts.
http://www.nostalgiaair.org/pagesbymodel/479/M0013479.pdf
RE: Philco 42-1002P parts values question - morzh - 11-20-2016
Yes 5W is enough. I would not touch the candohm, it dissipates very little, just above 1W and even that only if the lightbulb is gone.
250V is enough.
RE: Philco 42-1002P parts values question - Jim Koehler - 11-20-2016
What works nicely are the Dale bolt on resistors. Once these candohm assy's start going, the smart money is to replace the whole unit. With the proper Dale resistors replacing each section in a Candohm, you have your resistor taps right there. The biggest worry is how many holes you're going to drill on the rear apron (or wherever the old unit was mounted).
Another point is some candohms run HOT! This would be the perfect opportunity to bring up the wattage on that hot running section....easily done with a Dale resistor.
They're low in profile so they fit in about the same footprint of the Candohm also.
RE: Philco 42-1002P parts values question - ccomer1955 - 11-22-2016
I had not seen those before. They are perfect. This candohm only has a single section at 50 ohms and still measures as good. Mike mentioned the pilot light, and it is the only one of its kind I've seen. It is about the size of a smaller old-fashioned Christmas light. I thought it was tacked in, but the soldering and the base look to be factory.
The filament string seems intact, and the only replacement on the set looked to be a .05 cap R16 from the 7B7 grid to 1st IF.
Just be sure because I haven't worked with loctals all that much, but you do count the pins from either side of the lug that hangs down from the center post, right? Not the open space opposite the lug? So in the photo below, C9 (the .2 cap with the hand-made choke on it) is connected to pin 4 which isn't used on the 7C6, so it's just a tie point?
RE: Philco 42-1002P parts values question - morzh - 11-22-2016
Loctals same as octals, you count from the key clockwise when looking at the pins (bottom view).
yes they did use unused pins as soldering posts.
RE: Philco 42-1002P parts values question - Radioroslyn - 11-22-2016
The cap w/the coil around it is to help block out long wave stations from being amplified in the IF stage and causing interference. LW activity is pretty low theses days so interference isn't a problem. Short answer is you need the cap but not the coil. If you want to keep it original looking you can restuff the old cap and keep the coil.
Loktal tubes can be a little problematic as the steel pins get oxidized and cause a intermittent or bad connection. It's good practice to clean the pins w/some Deoxit and plug it in and out of the socket a few times. Some lock in really well and are difficult to remove, a very small amount of grease to the index pin in the center works for me. They can really be a pita in portable because of the lower voltages and hi impedance.
RE: Philco 42-1002P parts values question - morzh - 11-22-2016
I don't like loctals.
One thing, as Terry said, pin oxidation.
The other, I have to look underneath to figure what direction to tilt the tube to unlock it. Sometimes this is inconvenient.
And the very tilting itself might be inconvenient if the space is tight and you are pressing on some other component with the tube you are tilting.
RE: Philco 42-1002P parts values question - KCMike - 11-22-2016
There should be an bump on the side of the base of the loctal tube that pinpoints the direction to tilt the tube.