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

Safe to powerup without Speaker?
#16

Keith

I am not sure what you've done so far, but recap, recarb AND checking your tubes for 1) being what they should be and 2) being functional are the steps you should not skip.
#17

The first thing I did was test my tubes but my bi-focals didn't catch the 7G7 swapped for a 7B7. All of the out of spec resistors have been replaced along with all the paper and electrolytic caps. From now on I will double check all tubes to make sure they are what they should be.
Keith
#18

7G7 is a sharp-cutoff pentode; 7B7 is a remote-cutoff pentode. You need a 7B7 for proper AVC action.

7AH7 is the preferred substitute but 7A7, 7H7 and 7T7 will also sub.
http://www.nj7p.info/Tube/SQL/Tube_query.php?Type=7B7

--
Ron Ramirez
Ferdinand IN
#19

Thanks Ron,
I'll order a new tube but it sounds like the7G7 tube probably isn't what's causing the loud ticking sound.
Keith




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 46-480 Electronic Restoration
I’ve asked if they accept PayPal as payment so that I can contest it if the part doesn’t arrive.jrblasde — 12:46 PM
Philco 46-480 Electronic Restoration
Make sure th eperson who answered is not a scammer (lots of these there now) and the Trus A S, whoever they are and wher...morzh — 12:38 PM
Philco 40-120C Filament Wiring
I would disregard everything that is there now. I do not know who and when changed it. 1. Make sure that what you thi...morzh — 12:36 PM
Model 27-84 BUZZ?Humm?
Depends on the type of hum. SOme is made by outside devices. Try installing an X-cap (0.2-0.5uF) across the AC line, ...morzh — 12:23 PM
Philco 40-120C Filament Wiring
Thank you for your replies. That is the correct schematic and pin out diagram for the rectifier. The resistance acro...bluecap — 11:01 AM
Philco 46-480 Electronic Restoration
Late last night a guy reached out in response to my posting on the Antique Radio Forum and suggested I contact Trust Aut...jrblasde — 11:01 AM
Philco 630csx power cord
Have you opened up that plug? It may be that the third wire is connected to that brass stud on the side of the plug and ...Arran — 02:57 AM
Model 27-84 BUZZ?Humm?
I would have to look at the schematic but it's not uncommon in 1930s AC radios to have the negative of one filter cap co...Arran — 02:46 AM
Model 27-84 BUZZ?Humm?
Hello Bruce, First all do mean a 37-84b ? Did you take any before and after pictures ? is it a buzz like when you touch...radiorich — 01:59 AM
B&K 1077B no video - problem solved
Hello Tim, Yes, I even check all of my replacement parts when I install them and I too had a capacitor go bad not long a...radiorich — 01:54 AM

[-]
Who's Online
There are currently 2830 online users. [Complete List]
» 2 Member(s) | 2828 Guest(s)
AvatarAvatar

>