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

grid voltages
#1

Any one with an idea as to what g1 volts shoud be for a 650. I have distorted audio (clipped) and suspect the 78 tube is bad but G1 voltages would be a help for the whole set as well.

Dave Casazza
Keep em glowin and goin...
#2

The reason G1 voltages aren't typically shown is that they will measure differently with different types of meters because of the loading effects.

One approach is to simply use the specs from a tube manual (or online tube data source) http://tdsl.duncanamps.com/ and you MUST use a meter with a high input resistance. Modern Digital meters or VTVMs generally fit the bill and they didn't have them back in those days.

Where there is a cathode resistor involved the cathode voltage will often tell the story but that requires that the tube be in good shape.

Could you describe your distortion a bit more? Normally neither of the 78s would account for that. Have you recapped the set ?




Users browsing this thread:
[-]
Recent Posts
Restoration of the Canadian General Electric A-87
Well... The console body has been restored, while the varnish dries reliably I started to paint the chassis ...RadioSvit — 07:12 AM
Philco Model 38-7: what caps & resistors do fail typically?
Hello Martin, Welcome aboard our little community what great Model 38-7 Sincerely Richardradiorich — 12:30 AM
Philco Model 38-7: what caps & resistors do fail typically?
Welcome to the Phorum Martin. I count about 9 paper caps, the 3 electrolytic caps and 2-Y2 safety caps to replace th...RodB — 09:44 PM
Part numbers to model cross
Jim, We have this index put together by Dale Cook but I don't think that is quite what you are looking for. The Parts...klondike98 — 09:37 PM
Philco Model 38-7: what caps & resistors do fail typically?
Yep the dim bulb test is OK but I'd definitely replace all those electrolytics before I did it. Since those #47 conden...klondike98 — 09:18 PM
Philco 42-345 Restoration/Repair
The resistor is a 2.2 Meg, it was the last one I hadn't replaced. The broadcast is coming in after replacing it.osanders0311 — 09:09 PM
Philco 42-345 Restoration/Repair
What does the resistor measure? I think it should be 3.3 Meg. If the oscillator coil has continuity and the resistanc...RodB — 09:03 PM
Philco Model 38-7: what caps & resistors do fail typically?
Good idea to check the coils... then I'll get hold of an incadescent light bulb and see what happens when the unit is sw...Musaeum — 08:49 PM
Philco 42-345 Restoration/Repair
I have that same set, ain't too much shortwave I like anyway.....it is a good AM DX set. PaulPaul Philco322 — 08:32 PM
Philco Model 38-7: what caps & resistors do fail typically?
Welcome to the Phorum, Martin! Open a new thread in Philco Electronic Restoration when you begin working on your 38-7. ...GarySP — 08:28 PM

[-]
Who's Online
There are currently 903 online users. [Complete List]
» 2 Member(s) | 901 Guest(s)
AvatarAvatar

>