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

Model 60 Rectifier Circuit
#1

Am working on a Mod 60 using schematic #164. Put in new electrolytic caps, and rebuilt the filter condenser bank. Checking the voltage across Cap 46 I see 260vdc, across Cap 45 is 40vdc. Is this correct? The transformer AC volts check okay. Also checking the plate volts of the 6A7 pin 2 to pin6(K) I see nothing should be 250vdc. I don't understand what K means.
Thanks for any help
Bob
#2

Any tube pin marked as "K" generally means cathode, that's often used as a reference point for checking voltage since it's the closest point to ground potential in the circuit.
Regards
Arran
#3

Hi Bob
Not sure what diagram you are using? Can you post a link to it? Typically K stands for cathode in regards to tube connections. You aren't going to find any HV there, look for P would be the plate. That's where the HV should be.
Terry
#4

Read the OP again. He's saying that he's measuring from the plate of the 6A7 (pin 2) to the cathode (K, pin 6), between which should be 250V, but he is seeing no voltage there.

As far as his power supply voltages, I would check the bias resistor (47), and then the field coil on the speaker. No voltage at all to the 6A7 plate could be a shorted capacitor (20) or possibly an open 1st IF coil or resistor (9).
#5

Thank you everyone. These tips are (will be) a great help. Won't be able to get back to the radio for a day or two. I will post what I find.
Bob
#6

Making some progress. Replace Cap 8 and now have around 220 (not 250) volts on the plate of the 6A7. All I get out of the speaker is static whenever I touch the meter to pin 6 and the plate pin2.
I now have 350 vdc across cap 46 and 240 across cap 45. The speaker coil and resister 47 appear to be good. Is the difference between the voltages correct, or should they be the same.
What would be a god next step?
Bob




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
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
Philco model 38 code 121 not receiving signal.
Well why not! :lol:Stormlord5500 — 03:14 PM
Philco model 38 code 121 not receiving signal.
Good luck next thing you know you will be winding coils just for the fun of it. DavidDavid — 11:29 AM
Testing a speaker and output transformer Trutone A2-G
morzh Short-circuited turns can be considered as a half-dead transformer. But on this case transformer will hot and s...Vlad95 — 11:01 AM
Testing a speaker and output transformer Trutone A2-G
I am not sure how a transformer could be weak. It could be inadequate, but only when you replace the original with somet...morzh — 09:56 AM

[-]
Who's Online
There are currently 2138 online users. [Complete List]
» 1 Member(s) | 2137 Guest(s)
Avatar

>