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Restoring Philco 38-12 in a wood cabinet
morzh
Odobenus rosmarus
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Posts: 15,974
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Joined: Oct 2011
City: Jackson, NJ
#3

08-19-2024, 10:16 PM
Today I replaced or parallelled (if the deviation was not too large) the resistors.
One particular resistor puzzled me for a while.
It showed 7.3M and it should've been 190K. I 've seen my share of open resistors...but the radio worked fine.
I have another chassis I keep on the bench for reference; it was acquired independently about 2 years ago for $5. In good shape.
So, I looked at the same resistor there, and it showed....10M. I started doubting myself. I even thought it was some variation. I tried to look for 190K resistor but to no avail. Then I measured the voltage on the plate of the IF, where that resistor was the load, and saw 20V instead of 90V.
So I replaced it, and the voltage came back normal. The radio worked the same way as before.
I never saw two resistors in two chassis failed the same way. Bad batch?


Spare chassis' resistor
   
Its resistance
   

My chassis' resistor
   
Its resistance
   


Now just replace the electrolytic caps.
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.
(This post was last modified: 08-19-2024, 10:18 PM by morzh.)
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RE: Restoring Philco 38-12 in a wood cabinet - by morzh - 08-19-2024, 10:16 PM



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