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 328 Early
#24

Those voltage readings look much more reasonable. The B+ voltage is still a bit high, but this might be a result of todays higher line voltages. The AK schematic specifies a 110V AC line voltage, so you might want to use a bucking transformer or run the set on a variac.

It still appears that one of the 6K7's or the 6A8 is causing the positive grid bias on the AVC line. In normal operation, there should never be a positive voltage on the grid caps. The schematic voltages don't show polarity, but the 5V indicated on the 6K7 grids should be -5V, which would be typical when receiving a station.

You can disconnect one grid cap at a time and see which tube is causing the positive voltage. A gassy tube will produce a positive grid voltage and throw off the bias on all the remaining AVC controlled tubes. The positive grid bias is causing excessive plate current, which results in the higher than normal voltages across R3, R6, R10, R11 and R12.


Messages In This Thread
Atwater Kent 328 Early - by Eric - 09-24-2013, 08:09 PM
RE: Atwater Kent 328 Early - by Radioroslyn - 09-24-2013, 09:22 PM
RE: Atwater Kent 328 Early - by Eric - 09-25-2013, 11:32 AM
RE: Atwater Kent 328 Early - by Mondial - 09-25-2013, 02:51 PM
RE: Atwater Kent 328 Early - by Eric - 09-25-2013, 06:14 PM
RE: Atwater Kent 328 Early - by marty - 09-25-2013, 06:33 PM
RE: Atwater Kent 328 Early - by Eric - 09-25-2013, 07:31 PM
RE: Atwater Kent 328 Early - by Arran - 09-25-2013, 10:35 PM
RE: Atwater Kent 328 Early - by Eric - 09-25-2013, 11:08 PM
RE: Atwater Kent 328 Early - by Mondial - 09-26-2013, 12:05 AM
RE: Atwater Kent 328 Early - by Arran - 09-26-2013, 12:08 AM
RE: Atwater Kent 328 Early - by Eric - 09-26-2013, 03:18 PM
RE: Atwater Kent 328 Early - by Eric - 10-06-2013, 11:29 AM
RE: Atwater Kent 328 Early - by Mondial - 10-06-2013, 11:51 AM
RE: Atwater Kent 328 Early - by Eric - 10-07-2013, 08:54 PM
RE: Atwater Kent 328 Early - by Eric - 10-08-2013, 06:56 PM
RE: Atwater Kent 328 Early - by Mondial - 10-08-2013, 08:28 PM
RE: Atwater Kent 328 Early - by Eric - 10-09-2013, 11:10 AM
RE: Atwater Kent 328 Early - by Eric - 10-09-2013, 05:15 PM
RE: Atwater Kent 328 Early - by Mondial - 10-09-2013, 06:39 PM
RE: Atwater Kent 328 Early - by Eric - 10-10-2013, 03:28 PM
RE: Atwater Kent 328 Early - by Mondial - 10-11-2013, 08:31 AM
RE: Atwater Kent 328 Early - by Eric - 10-11-2013, 08:15 PM
RE: Atwater Kent 328 Early - by Mondial - 10-11-2013, 11:16 PM
RE: Atwater Kent 328 Early - by Eric - 10-12-2013, 11:38 AM
RE: Atwater Kent 328 Early - by Mondial - 10-13-2013, 10:31 AM
RE: Atwater Kent 328 Early - by Eric - 10-13-2013, 12:18 PM



Users browsing this thread: 5 Guest(s)
[-]
Recent Posts
1930s Stewart-Warner Tombstone Radio need help identifying model number
Another Update: I found a couple of damaged coils inside this radio that might have something to do with why this radio ...captainclock1988 — 10:51 PM
6TPZ and 5TPO Radio Help
If you are still on 5TPO, you lost me there. What X7? What Points 1 and 2?morzh — 08:37 PM
6TPZ and 5TPO Radio Help
Quick progress report: X7 is broken. Only one leg soldered, the other missing and the diode is cracked. I've replaced...R3Sons — 05:05 PM
6TPZ and 5TPO Radio Help
Oh...and you have electrolytic caps there. All need to go and be replaced.morzh — 04:36 PM
6TPZ and 5TPO Radio Help
Thanks, will do.R3Sons — 01:25 PM
1930s Stewart-Warner Tombstone Radio need help identifying model number
UPDATE: I was able to pick up a signal generator on the cheap (amazingly enough) on feebay and I did an IF alignment fol...captainclock1988 — 09:53 AM
Philco 91 Schematic
Hi Rod, The resistor connects to pin 4 and the ungrounded side of block 9. From pin 9 of the RF tube to one side of ...dconant — 09:34 AM
Just got a 49-1613 need to know...everything!
I just found your post. I have this exact same model, and have had it since 1985 when I was 15 years old! I performed a ...MuzzcoVW — 09:11 AM
B&K 1077B no video
Hello Tim, I would if it's a leaky Capacitor So are all 3 of those B- voltages low then ? Sincerely Richardradiorich — 01:55 AM
B&K 1077B no video
I found a schematic and think I have the problem traced down to the minus power supply. I have very low voltages that go...TV MAN — 12:41 AM

[-]
Who's Online
There are currently 7076 online users. [Complete List]
» 3 Member(s) | 7073 Guest(s)
AvatarAvatarAvatar

>