Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

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

Quick Question about a Schematic..
#46

So.....where the other plate powers that were supposed to be connected to it were connected?

In short, what I am trying to understand, have you asked yourself and answered these questions? Is everything connected according to the schematic now?
#47

Your question about what was powering the tubes, it made me look further. Remember when I said that nothing is connecting resistor #55 to the cap? .. Well, one of those three wires I mentioned (from resistor #55), it runs to the RF, but then another wire was connected from that point to the other #67 cap (call it wire #2). Basically the problem was, everything was hooked up to one single 8mfd cap. That's where the hum was coming from! I removed the wire I installed, and moved the wire #2 to the other #67 cap. All is fine.

This radio had been worked on before I got it. The Electrolytic Caps were replaced sometime back in 1945 (from the looks of it). I just replaced parts, so I don't know if I made the wiring mistake or if I just copied it. I recapped this radio back in the summer. It was one of the first radios I ever repaired, so it could have been my fault. I put it aside because it hummed. It has not been used since.

Anyways, the problem is fixed, and a huge thanks to everyone who helped me, especially Morzh!. I learned more everyday.

The artist formerly known as Puhpow! 8)
#48

If you look at the sch with one #67 being at the top (or at the right most) and another being inside (closer to the 80 tube) - if all was connected to the top cap it would hum as this is the "unfiltered" voltage; the filtered one (by the field coil) goes to the one close to the 80 tube and this is where all those RF power and #55 resistors should've gone to.

Anyway, all is well that ends well.

Good job!
#49

You know, I had gone over that schematic 100 times and I couldn't see the error. I swear, I spent hours looking at this radio. Now that I found it, I don't know how I ever missed it. Sometimes it's like unraveling spaghetti. I think I am getting better, but I don't know. Thanks a million Morzh!

The artist formerly known as Puhpow! 8)




Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
First Radio restoration
Hi Tubeman, Welcome to the Philco Phorum.  Phamily Phriendly Pfun with Phine Pholks Phull of Philco Phacts. (See a p...MrFixr55 — 12:33 PM
First Radio restoration
You could post in the WANTED ADs section here on the Phorum and see if anyone has an RF generator that they want to sell...klondike98 — 11:55 AM
Zenith H725
Good ideas, thank you Arrange and Rich. I have the adhesive aluminum foil already and can try that immediately. More ...EdHolland — 10:18 AM
Graphics for majestic 1050 dial glass.
Murf; I found this thread on the ARF, the first photo has a pretty good view of the dial glass. Regards ArranArran — 01:12 AM
Zenith H725
hello Ed, how about that speacial tape used for ducting it's like foil or how about thin piece of aluminum roof flash...radiorich — 12:19 AM
Zenith H725
Ed; One material that I have seen, but never tried for this was material for making exhaust gaskets, it's similar to ...Arran — 11:42 PM
Zenith H725
I just remembered, I have some hi temp silicone rubber material which could do the trick. Or a piece of FR4 laminate. Th...EdHolland — 08:39 PM
Zenith H725
The PSU filter cap arrived today (thank you USPS!) so I will work on that later. Meanwhile, I have the dial, speaker...EdHolland — 06:42 PM
Philco 610B oscillator wiring
Thanks Terry. After checking my notes I think I recorded about -10v at the 6A7 G4/control grid. The screen grid (G3 &...Tubester — 05:59 PM
The list of my radio & TV collection!
Magical chords of forgotten melodies, old nostalgic music on an old radio... Saturday night blues on the Mid-Waves on an...RadioSvit — 12:20 PM

[-]
Who's Online
There are currently 2198 online users. [Complete List]
» 3 Member(s) | 2195 Guest(s)
AvatarAvatarAvatar

>