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

The innards of that AK 20 Big Box set
#16

I have all three dials representing the same physical position for the gangs, now. And I did in fact already replace the resistors. One of the old wire wound ones was open (and cracked), and the other was only showing 460 ohms, so I replaced both. I also replaced the by-pass capacitor and both interstage transformers.

I experimented with tubes a bit. I even put a 200a in as the detector, but that didn't work at all. The rest of what I have is a mix of 201a and 301a tubes that test really well in my Triplett (in the 80s and 90s) and one ST 01a that tests in the 60s. I moved the 01a to the audio stage, and have my strongest tubes in the RF spots and the detector. What doing that gave me when I connect the antenna was nothing at the antenna post, and strong volume and clear signal that is tunable when I move the antenna to the grid of the 2nd RF tube, and a really strong signal and volume at the lead on the screw of the tuning gang beside the detector that has a lead going to the grid leak resistor.

I've noticed the fins of the tuning gangs are also just a bit off center relative to each other. I see a set screw that would require removing the RF coils to get to, but it might be worth it to do a good cleaning and get the gangs exactly true.

So, the audio phase and detector are working, the third gang and 2nd RF seem to be OK, too. My problem is between the grid of the 2nd RF and the antenna post, right?

Am I missing anything? I feel like I'm just about there.

Charlie in San Antonio


Messages In This Thread
RE: The innards of that AK 20 Big Box set - by ccomer1955 - 06-29-2015, 06:26 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Need to purchase some accessories for restoration of my Old Philco Radio
Here is a list of resources found in our online library that you might find useful. Mike's Gobs of Knobs email addres...klondike98 — 01:46 PM
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

[-]
Who's Online
There are currently 2366 online users. [Complete List]
» 1 Member(s) | 2365 Guest(s)
Avatar

>