Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 1 Vote(s) - 1 Average
  • 1
  • 2
  • 3
  • 4
  • 5

41-610 High plate and grid voltages
#1

Greetings everyone,

     Working on a Philco 41-610P code 121. It's my desire to spend as little as possible (time or money) to figure out if it's worth saving. To start i did some basic repair to the unit,replaced the filter caps,repaired broken/chewed up wiring. Even managed to rewind a coil on the oscillator. I also replaced one cap that the mice completely chewed through. At this point i decided to power it up on a variac using the dim bulb method. At about 50v the indicator bulbs began to glow, drawing about 20 watts at this point. Slowly increased voltage. At about 80v ,30 watts  I started to hear faint noise as I let the radio warm up. I was able to tune in a local station.It sounded weak of course but the audio was distorted too. I checked plate and grid voltages which were kinda high, tube 41 plate was at 190v, schematic called for 165v, for example. Checking the other tubes revealed higher voltages as well. I then decide to re-cap the radio as most of the original caps were still in place and checked the resistors i could while i had the tubes out. I then slowly powered the radio back up. At about the same voltage on the variac i began to hear noise,tuned in the local station. Audio sounded much better. I then went up to 90v on the variac, drawing about 43 watts and the radio really came back to life. Audio was crisp and clear and was able to tune in more stations.Short wave and the phono amplifer also worked. I then checked plate and grid voltages and to my disappointment all were reading even higher relative to their rated voltages on the schematic. The 41 plate was now reading about 210 volts,should be 165.Voltage just after the rectifier but before the field coil was reading 250v,should be 225v. I can only guess what the voltages would be if i went any higher on the variac (roman candles came to mind).

    I was expecting lower voltages with the radios age. To me it seems like the radio isn't drawing enough power. My question is this, As tubes age do they tend to draw less power,causing voltages to rise? I don't have a tube checker yet,haven't really needed one up until now i guess. I'm having trouble zeroing in on any one cause of the higher voltages. In the forums experience,am I looking at a total rebuild? My experience is limited with antique radios,it is a hobby. I've repaired a half dozen or so pre 1960's radios with success. I'm kind of at a loss on this one. I attached the schematic i'm using.

Thanks in advance for any help or pointers.


Messages In This Thread
41-610 High plate and grid voltages - by atvman101 - 12-30-2019, 04:35 PM



Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
Atwater-Kent 84, restoration.
Well, powering it up would be too good to be true, and I had that feeling. Before I did, I decided to check the coils...morzh — 06:02 PM
An attempt to remove the Field Coil from a G speaker
Thanks Chas, sure will give it a look!morzh — 03:39 PM
An attempt to remove the Field Coil from a G speaker
Mike, Lookup  murrayatuptown on ARF. Seems he has a dilemma with surplus field coils. Could get lucky and have what y...Chas — 01:26 PM
Atwater-Kent 84, restoration.
Hello Mike, I have not checked to see if my console has a fuse or not and far as sets go I have early 30s General Motor...radiorich — 11:25 AM
Atwater-Kent 84, restoration.
Ron I forgot, but when you said "phone number", I remembered, caus I usually remember how I act when I need...morzh — 11:12 AM
Atwater-Kent 84, restoration.
You have an extensive collection of Philcos, Mike! I’m always excited to see each new one. Agreed on the power supply fu...jrblasde — 10:50 AM
462ron
Hi Mike, that 84 sure looks great. You don’t often see these antique radios with a fuse like yours has. I usually instal...462ron — 10:22 AM
Atwater-Kent 84, restoration.
Hello Mike, Wow ! far as my AK it does work and the cabinet is in nice shape so is my chassis anyway here is a photo of...radiorich — 02:59 AM
Atwater-Kent 84, restoration.
Nice radio, Mike! Here's hoping it was well rebuilt. Take care and BE HEALTHY! GaryGarySP — 12:12 AM
Atwater-Kent 84, restoration.
Rich yes, this is the way I got it. I have just put it on the table and took it apart. I suspect it even might work,...morzh — 11:31 PM

[-]
Who's Online
There are currently 4481 online users. [Complete List]
» 1 Member(s) | 4480 Guest(s)
Avatar

>