Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco 87 alignment question/RESULTS
#1

Where, exactly, am I hooking up the output meter (VTVM). It says the "voice coil" and I want to be certain. And I'm measuring VAC, correct? And where do I get the non-metallic 1/4" hex socket tool to turn both the RF adjustments and then the compensators for neutralization?
#2

Hi

It is most convenient to connect your output meter across the speaker voice coil.

As to where to find the 1/4" hex tool for alignment, you may have to make your own. See these threads for more details.

http://www.philcoradio.com/phorum/showth...hp?tid=242

http://philcoradio.com/phorum/showthread.php?tid=1544

http://www.philcoradio.com/phorum/showth...p?tid=4148

--
Ron Ramirez
Ferdinand IN
#3

OK, thanks. In the meantime, I had the radio on and what does this tell you: with no antenna wire or ground, I get the three strong stations crystal clear. However, the volume control does nothing. They are all at about the correct listening level, but I can't increase or decrease the volume. (I've checked the pot with my DVOM and it's fine) Adding my long wire does not increase the signal or volume. Now if I go up to a station 25 miles away (580), I need the long wire and at that station, the volume works as it should. If I tune down to 910 ( a strong local station), I still can't turn it down in volume. That control on the far right has some effect, but I can never get a strong station to go from nothing to very loud.
#4

The "volume control" on the 87 is just a 10K potentiometer connected between the antenna terminal and ground. On sets like these, a good ground is essential for proper operation of the volume control. Left ungrounded, the volume control is not always effective on strong local stations, as you have discovered.

--
Ron Ramirez
Ferdinand IN
#5

I made my alignment tool and everything went by-the-books, so to speak, until the very last step. (RF tubes 3rd and 2nd received only a minor adjustment to get a minimum signal) The first RF tube's neutralization condenser showed the meter going down as I turned it. The more I turned it, the more it went down. It felt super loose. So I took it back to where it was before and, of course, the meter went up until I could turn the condenser no more. No matter what changes I made, the results were always repeated. I disconnected all of the test equipment and turned the radio on and I would describe the operation as completely satisfactory. If I adjust the first condenser now, it merely lowers the signal. So it's more or less where it was before. When I have the ground connected, the set works much better, but without it is not bad at all. If I stick a 2' wire on the antenna post (and no ground), I can pick up my 4 strong stations crystal clear and the Volume Control works. What it the control on the right side called?
#6

More or less it's a local/distance switch. It turns off the first RF amp stage.
Sounds like you got it working great!!!! Good set for 1929. Gotta stick a cap
or two in mine to get it working again. Enjoy it!!!!!
Terry

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry




Users browsing this thread: 1 Guest(s)