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

Philco 37-610 Thump*No 7 Volts to pilot lamp
#16

Hi Ralph,

Other experts please chime in if I am wrong here. Most restorers will accept up to a 20% error in the resistor value for older radios because most of the resistors have a tolerance of 20%. Replacing the 2 resistors with the lower values that you described would still put you in about a 10% error. since they are oth 10% lower, in theory, the voltage would be no different than the theoretical design voltage.

Much has been said by others responding to your post, all very good info. do consider reheating solder connections, ohming coils, and verifying circuit continuity through the band switch. Definitely verify grounds. Consider bonding ground points to each other if the chassis is rusty.

If you have a signal generator, it would be a useful tool in troubleshooting this issue.

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis

Best Regards, 

MrFixr55
#17

I agree with MrFixr regarding resistor replacement tolerances.

Joe

Matthew 16:26 "For what does it profit a man if he gain the whole world, yet lose his own soul?"
#18

20% seems to be the commonly accepted tolerance. Keeep in mind, this is +/-20% which makes it 40% (counting from the center value) range.
It's possible there are some places where one might want a tighter tolerance, but most will be OK with 20%.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#19

Keep in mind we don't really know what values the engineers came up with. All we see is what is on the drawing and what is inside the chassis. They used the closest component value to what the calculated one was, plus the parts manufacturers couldn't get much closer than 20% for standard parts. It's evident that cost often determined the final parts placement (what do you mean I can't add fidelity?). So this is why I use 10 percent tolerance. Plus, it's easy to calculate.
#20

Mr Fixr,

I have replaced resistors #22,23 and 47                                                                                              All voltages are with in 20% except 6K7 plate voltage is 63v not 175v
With power off 0 ohms between pin 5 and ground.
No stations when touching grid cap of 6A8. When testing with another radio I did not get any squealing. When moving the radio outside I did get 3 stations fainty with a .1 cap on screw #1 of the antenna with screws 2 and 3 jumped and me touching the cap. No stations when using wire for a antenna.
2 things did happen while trying to get it to play. playing with grid cap of 6K7 I got some motor boating also when wiggling the center chassis I could get the motor boating to come and go. Do I need to replace the grommet's on the center chassis?
The antenna lead going to the band switch needs to be resoldered, the radio shows its not a good connection when wiggling the wire. Looks very hard to get at the soldering point of the band switch.

Ralph




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-345 Restoration/Repair
Yes, 57 is an electrolytic cap that should be 12 mfd 400 volts according to the parts list from the Phorum library schem...RodB — 06:01 PM
Philco 42-345 Restoration/Repair
Looks like if I am reading it correctly it looks like the silver capacitor#57 that appears to be a replacement is of a l...osanders0311 — 05:09 PM
Philco model 38 code 121 not receiving signal.
Thanks Arran. Yeah this plastic is pretty thin. It's a little thinner than the original stuff. It kinda reminds me of p...Stormlord5500 — 04:37 PM
Testing a speaker and output transformer Trutone A2-G
The equivalent of one short turn is basically the same as that of a shorted load. If it is the primary's turn, then the ...morzh — 03:53 PM
Testing a speaker and output transformer Trutone A2-G
I've never had an output transformer become shorted, the failure mode is usually an open primary, or in a center tapped ...Arran — 03:52 PM
Philco model 38 code 121 not receiving signal.
As long as the plastic sheeting isn't too thick, I think that the thickness of photographic film would be just about rig...Arran — 03:19 PM
Philco model 38 code 121 not receiving signal.
Well why not! :lol:Stormlord5500 — 03:14 PM
Philco model 38 code 121 not receiving signal.
Good luck next thing you know you will be winding coils just for the fun of it. DavidDavid — 11:29 AM
Testing a speaker and output transformer Trutone A2-G
morzh Short-circuited turns can be considered as a half-dead transformer. But on this case transformer will hot and s...Vlad95 — 11:01 AM
Testing a speaker and output transformer Trutone A2-G
I am not sure how a transformer could be weak. It could be inadequate, but only when you replace the original with somet...morzh — 09:56 AM

[-]
Who's Online
There are currently 2219 online users. [Complete List]
» 2 Member(s) | 2217 Guest(s)
AvatarAvatar

>