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

Newbie Model 71 questions
#3

Hi and Welcome to the Phorum,

>Are there any critical wire lengths that I shouldn’t alter as I clean up and rewire?

Generally speaking wiring should be neat, close to the chassis when possible and not excessively long. Wiring that can create problems are if heater wiring is near control grid wiring (can induce 60cy hum) and if control grid wiring is near plate wiring (can induce unwanted feedback).

>Part  (21) Filter Condenser Bank ( 2x0.05u, 1x0.25u)  04731 appears to be missing. Three caps numbered (21) appear on the schematic but I don’t know which of them is the 0.25u.

On #21 the .25mf should be connected to the center tap of the power transformer's hv winding. The .25 may have been replaced by a small electrolytic like 10 or 20mf @35v + side to the chassis and - to the ct.

>Part (38) 3903AA  and line filter caps (49) are also missing also missing but I can work around those.

OK

>The tone control (39) appears to have an integrated cap but the schematic shows no value. Any suggestions?

Value is not very critical it just determines how much high frequency response it cuts off. Larger the cap the less highs you will hear. Typically a .01 or .02mf  at a 630v or higher voltage.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry


Messages In This Thread
Newbie Model 71 questions - by gmg - 03-13-2017, 07:43 AM
RE: Newbie Model 71 questions - by TV MAN - 03-13-2017, 02:37 PM
RE: Newbie Model 71 questions - by Radioroslyn - 03-13-2017, 03:42 PM



Users browsing this thread: 4 Guest(s)
[-]
Recent Posts
RCA T62 is playing.....
Beautiful set.morzh — 09:07 PM
An attempt to remove the Field Coil from a G speaker
Well....here it is. The green stuff. Unfortunately, probably penetrates deep. I opened the top layer and saw that: ...morzh — 08:58 PM
Philco 91 Restore Code ??
:clap: :clap: :clap: :clap: Really nice workmanship!!! Top of the chassis looks great. Sorry about the long winded e...MrFixr55 — 08:09 PM
Philco 40-120C Restoration
Thank you for your reply. I will check voltages on the other tubes, look at resistor 23 and cap 25, etc. If all else fai...bluecap — 07:58 PM
RCA T62 is playing.....
Nice looking set great save. DavidDavid — 07:48 PM
Philco 89 indicator light.
Hello Jim, I have done several 89s. The trick is to move the drum in or out on it's shaft. You will need to loosen a set...dconant — 07:36 PM
An attempt to remove the Field Coil from a G speaker
MrFixr Yes, it is my plan to go with 45rpm spider if I go that far. No, the pole was not left-handed as I unscrewed ...morzh — 07:14 PM
Philco 40-120C Restoration
Change the tube. Check the tube's bias network. Are any other tubes experience the drop or just this?` Is resistor 23 OK...morzh — 07:09 PM
Philco 89 indicator light.
I forgot how the pointer is formed: could you show the way it is formed and how you tried to change it?morzh — 07:01 PM
An attempt to remove the Field Coil from a G speaker
Was that pole piece left handed ? Since the metal "spider" is toast, wonder if you can either get the "4...MrFixr55 — 06:54 PM

[-]
Who's Online
There are currently 7450 online users. [Complete List]
» 3 Member(s) | 7447 Guest(s)
AvatarAvatarAvatar

>