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

38-8 high voltage problem
#1

i have a problem hope you can help i have high voltage on these tubes
6a8 pin 3 spec 180v have 325v...
6F6 pin 3 spec 230v have 348v pin 4 spec 250v have 326v
6K7 pin 3 spec 240v have 306v
5Y4 pin 7 spec 100 have 358v
other tube pins are OK with in 10-15 volts of specs the radio plays very little distortion sounds a little tinny could be speaker has small tear

2 resistors #12 13K 10 watts & #22 51K 2 watts are getting hot,, transformer is cool and does not show any shorts I've check caps and rest for ground problems can't find any so far
can you point me in the right direction
thank
john
#2

For a starter, I'd try to measure just how much current is going through the B+ using an old-fangled ammeter. Anything over 50-75 m.a. wouold be suspect. Suba P.M. speaker and see if the audio is clear. I assume you are meauring from B- to point in question, or however the schematic you have says how to do it.
#3

i have checked to amps at # 12 13K 5 wt resistor and it read 10.56 ma so that seems OK maybe that resistor just gets warmer because its 5wt er,,,it still get a little distorted after its been on for 5 min or so still checking out the speaker is proving a bear it has a HS style speaker and you can't just put a pm in its place looking for a way to put a pm with out blowing up the radio
thank again for all the help
the old geezer
john
#4

IMO your 6F6 is gassy, or there is trouble in your cathode bios, and of course it is possible that coupling capacitor is bad. Chaiged all of 'em out?




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
VTVM meter moves when my hand is next to it & not on
Haha! I hope so. It seemed rather lost and forgotten languishing in the frozen Northeast of England.EdHolland — 02:36 PM
VTVM meter moves when my hand is next to it & not on
Ed - it's in the Cayman's enjoying the good life.RodB — 02:14 PM
VTVM meter moves when my hand is next to it & not on
Static electricity - but the other chaps beat me to it again. I've seen this before with analogue meters. I've also ...EdHolland — 01:56 PM
Need to purchase some accessories for restoration of my Old Philco Radio
Hi Paulo, Welcome to the Philco Phorum. I can see why you want to find good reproduction parts. That is a bea...MrFixr55 — 11:10 PM
HiFi (Chifi) tube amp build - but my own design.
Tim, I have some bakelite sockets in my work shop that I can dig up. I believe quite a few are NOS. I will take photo...RodB — 10:03 PM
Philco 610B oscillator wiring
> The cathode as noted is wired directly to the ground side of the heater filament for that tube, not to the #17 and ...Radioroslyn — 08:12 PM
HiFi (Chifi) tube amp build - but my own design.
Tim; I noticed your post a little late, but I would take one of the junk sockets and try to break a chunk out of it wi...Arran — 08:07 PM
Need to purchase some accessories for restoration of my Old Philco Radio
Here is a list of resources found in our online library that you might find useful. Mike's Gobs of Knobs email addres...klondike98 — 01:46 PM
First Radio restoration
Hi Tubeman, Welcome to the Philco Phorum.  Phamily Phriendly Pfun with Phine Pholks Phull of Philco Phacts. (See a p...MrFixr55 — 12:33 PM
First Radio restoration
You could post in the WANTED ADs section here on the Phorum and see if anyone has an RF generator that they want to sell...klondike98 — 11:55 AM

[-]
Who's Online
There are currently no members online.

>