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

Atwater Kent model 20 Big Box
#3

When each tuning condenser is fully meshed, the cursor on the panel should point to 100...

So expect that the radio will not tune all of the BC band and may only reach 1350Khz and no higher.

Although the speaker clicks the diaphragm may rattle..

The type of driver in the speaker will determine if polarity of the speaker leads ar to be observed. If there are (+) and (-) markings on the driver, connect the (+) wire to the B+ and the (-) to the plate circuit of the last audio tube...

If the driver is the bi-polar pin driven diaphragm motor the polarity is not important.

Be best to find used A-K transformers for the set. The audio transformers can be rebuilt by using modern units that have a high resistance primary. Some modern make-do replacements lack the primary resistance the net result is low volume and/or distortion...

If this is your first 20's battery set, be aware that scrimping on the power sources can also introduce problems like oscillation, poor sensitivity and poor volume. An absolute must is the "A" supply of at least 6 to 6.6 volts, even though the tubes are 5 volts. The reason is the rheostats lower that voltage and the difference is part of the tube bias. The rheostats also control the volume and detector sensitivity. The "B" battery must also have a low impedance using 9 volt transistor battery's will work but the set can oscillate. There is a chassis mounted cap in a metal can the should either be "stuffed" or replaced. This cap helps prevent oscillation.

http://www.atwaterkent.info/TechData/Dra...640sch.pdf

The url will help with the tubes:

http://www.nostalgiaair.org/References/A...lash08.htm

Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”


Messages In This Thread
Atwater Kent model 20 Big Box - by TTech - 04-18-2021, 05:49 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-18-2021, 05:53 PM
RE: Atwater Kent model 20 Big Box - by Chas - 04-18-2021, 06:56 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-18-2021, 09:56 PM
RE: Atwater Kent model 20 Big Box - by Chas - 04-19-2021, 12:51 AM
RE: Atwater Kent model 20 Big Box - by TTech - 04-19-2021, 10:14 AM
RE: Atwater Kent model 20 Big Box - by Chas - 04-19-2021, 11:46 AM
RE: Atwater Kent model 20 Big Box - by Eliot Ness - 04-19-2021, 01:31 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-19-2021, 05:59 PM
RE: Atwater Kent model 20 Big Box - by Chas - 04-19-2021, 07:47 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-19-2021, 08:52 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-20-2021, 09:47 AM
RE: Atwater Kent model 20 Big Box - by Chas - 04-20-2021, 11:28 AM
RE: Atwater Kent model 20 Big Box - by TTech - 04-20-2021, 12:15 PM
RE: Atwater Kent model 20 Big Box - by Chas - 04-20-2021, 02:29 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-21-2021, 08:19 AM
RE: Atwater Kent model 20 Big Box - by Chas - 04-21-2021, 10:54 AM
RE: Atwater Kent model 20 Big Box - by TTech - 04-21-2021, 01:01 PM
RE: Atwater Kent model 20 Big Box - by Chas - 04-21-2021, 11:13 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-22-2021, 04:45 PM
RE: Atwater Kent model 20 Big Box - by Chas - 04-22-2021, 05:30 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-23-2021, 08:18 AM
RE: Atwater Kent model 20 Big Box - by TTech - 04-23-2021, 05:28 PM
RE: Atwater Kent model 20 Big Box - by Chas - 04-24-2021, 09:39 AM
RE: Atwater Kent model 20 Big Box - by TTech - 04-24-2021, 11:03 AM
RE: Atwater Kent model 20 Big Box - by TTech - 04-25-2021, 10:52 AM
RE: Atwater Kent model 20 Big Box - by Chas - 04-25-2021, 11:20 AM
RE: Atwater Kent model 20 Big Box - by TTech - 04-25-2021, 12:51 PM
RE: Atwater Kent model 20 Big Box - by Chas - 04-25-2021, 04:59 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-26-2021, 05:18 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-29-2021, 01:38 PM
RE: Atwater Kent model 20 Big Box - by Chas - 04-29-2021, 05:23 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-29-2021, 06:01 PM
RE: Atwater Kent model 20 Big Box - by Chas - 04-29-2021, 06:10 PM
RE: Atwater Kent model 20 Big Box - by TTech - 04-29-2021, 06:41 PM
RE: Atwater Kent model 20 Big Box - by Phlogiston - 05-01-2021, 04:15 PM
RE: Atwater Kent model 20 Big Box - by TTech - 05-01-2021, 08:18 PM
RE: Atwater Kent model 20 Big Box - by TTech - 05-02-2021, 02:02 PM
RE: Atwater Kent model 20 Big Box - by Phlogiston - 05-02-2021, 05:17 PM
RE: Atwater Kent model 20 Big Box - by TTech - 05-03-2021, 02:35 PM
RE: Atwater Kent model 20 Big Box - by TTech - 05-04-2021, 03:47 PM
RE: Atwater Kent model 20 Big Box - by TTech - 05-04-2021, 06:26 PM
RE: Atwater Kent model 20 Big Box - by Chas - 05-06-2021, 12:05 PM
RE: Atwater Kent model 20 Big Box - by TTech - 05-07-2021, 09:34 AM
RE: Atwater Kent model 20 Big Box - by TTech - 05-07-2021, 09:58 AM
RE: Atwater Kent model 20 Big Box - by Chas - 05-07-2021, 10:50 AM
RE: Atwater Kent model 20 Big Box - by TTech - 05-07-2021, 12:46 PM
RE: Atwater Kent model 20 Big Box - by Chas - 05-07-2021, 01:01 PM
RE: Atwater Kent model 20 Big Box - by TTech - 05-12-2021, 09:59 AM
RE: Atwater Kent model 20 Big Box - by admin - 05-12-2021, 10:26 AM
RE: Atwater Kent model 20 Big Box - by Phlogiston - 05-12-2021, 06:18 PM
RE: Atwater Kent model 20 Big Box - by TTech - 05-12-2021, 09:49 PM
RE: Atwater Kent model 20 Big Box - by Chas - 05-14-2021, 12:13 PM
RE: Atwater Kent model 20 Big Box - by OZ4 - 05-17-2021, 12:57 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
PT 6 chassis screws size???
Hello bridKarl, that sounds right or maybe 8/32 . Sincerely Richardradiorich — 01:00 AM
PT 6 chassis screws size???
Have this done except for missing chassis screws. It looks like 1 inch 6/32 sheet metal screw may work but can anyone s...bridkarl — 10:32 PM
Philco model 38 code 121 not receiving signal.
Hello Stormlord, Well done on rewinding that coil it turned fairly good for your first one. Sincerely Richardradiorich — 09:12 PM
Philco model 38 code 121 not receiving signal.
Well here it is. It ain't pretty, but hopefully it'll work. I checked it with my DMM on continuity and it keeps and r...Stormlord5500 — 08:56 PM
Philco 42-345 Restoration/Repair
Yes, 57 is an electrolytic cap that should be 12 mfd 400 volts according to the parts list from the Phorum library schem...RodB — 06:01 PM
Philco 42-345 Restoration/Repair
Looks like if I am reading it correctly it looks like the silver capacitor#57 that appears to be a replacement is of a l...osanders0311 — 05:09 PM
Philco model 38 code 121 not receiving signal.
Thanks Arran. Yeah this plastic is pretty thin. It's a little thinner than the original stuff. It kinda reminds me of p...Stormlord5500 — 04:37 PM
Testing a speaker and output transformer Trutone A2-G
The equivalent of one short turn is basically the same as that of a shorted load. If it is the primary's turn, then the ...morzh — 03:53 PM
Testing a speaker and output transformer Trutone A2-G
I've never had an output transformer become shorted, the failure mode is usually an open primary, or in a center tapped ...Arran — 03:52 PM
Philco model 38 code 121 not receiving signal.
As long as the plastic sheeting isn't too thick, I think that the thickness of photographic film would be just about rig...Arran — 03:19 PM

[-]
Who's Online
There are currently 661 online users. [Complete List]
» 1 Member(s) | 660 Guest(s)
Avatar

>