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
#17

There are two things that seem to stand out regarding your measurements. First the B+ voltage is rather high and second the voltage across R6 is abnormal.

The high B+ could be caused by a lack of load on the supply or a shorted speaker field, which normally would be dropping the voltage to the tubes at least 60 or 70 V. Check the resistance of the field winding and see what it measures. When operating, what is the voltage on each side of the field, measured to ground?

R6 is the cathode resistor for the 6K7 1st IF tube and there is no way there should be 54 V across it. It should be 1K, and with that voltage drop there would have to be 54 Ma passing through it and therefore the 6K7 tube, which is not likely. More likely R6 is bad and increases in value when it warms up. Have you tried replacing R6 as it might be the problem.

Edit- I just looked back at your previous post and saw you measured 278 V on the grid cap of the 1st IF 6K7 ??? Is that right? If so there must be a short to B+ in the 1st IF transformer or associated grid circuit, or the 6K7 has an internal short. Remove the grid cap (with the set powered down!) and then measure the voltage on the grid lead and the 6K7 cap separately to see which is supplying the HV. This might also explain why you have 54 V on the cathode resistor!


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: 1 Guest(s)
[-]
Recent Posts
The list of my radio & TV collection!
A little light Saturday positive about our hobby in our feed... My new every Saturday video about antique radio equipme...RadioSvit — 02:12 PM
Model 70 Cabinet Trim
musar , Well if you have any more questions feel free to post away . Sincerely Richardradiorich — 08:56 PM
Model 70 Cabinet Trim
Although I have not made any cabinets or cabinet parts for a couple of years, I still have some parts left over, includi...Steve Davis — 06:26 PM
philcorepairbench.com - shadow-meter
Thanks Ron. But I can't find those articles.fenbach — 02:43 PM
Model 70 Cabinet Trim
Thank you, Gary. Before making my original post, I had clicked on "Steve Davis Cabinets" only to find that it...musar — 02:25 PM
philco predicta
Welcome to the Phorum, cgl18! I am not your resource for television repair, but lots of friendly help is available here...GarySP — 02:12 PM
Model 70 Cabinet Trim
Welcome to the Phorum, musar! You can send Steve Davis a private message (PM). The site is at the top of the Home page...GarySP — 02:09 PM
Model 70 Cabinet Trim
How do I contact him? The only contact information for him I could find when searching online was a telephone number th...musar — 10:38 AM
philco predicta
Hello, good afternoon, I would like to ask what the possible problem could be if I don't have an image on the screen. I ...cgl18 — 10:19 AM
Philco model 38 code 121 not receiving signal.
So one last question before I finish this radio. Regarding the speaker and output transformer. I salvaged the original o...Stormlord5500 — 09:31 AM

[-]
Who's Online
There are currently 953 online users. [Complete List]
» 1 Member(s) | 952 Guest(s)
Avatar

>