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Philco Model 38-7: what caps & resistors do fail typically?
#20

I made my shopping list, and have a bunch of questions Icon_smile

  • Why is "microfarad" sometimes "mf" and sometimes "mfd"?
  • What is a compensator like  (7) and (7A) other than a capacitor?
  • Component 36 is a resistor (anode supply of 1st audio). Why is the unit "mf", and why such a strange value (99.000 ohms)?
  • Component 47, the Y-cap, says ".015-.015, 25mf". Is there a third capacitor of 25uF somewhere?
  • All resistors are quite large, even the 1/4 watt types. Any recommondation for the general type of replacement resistor, i.e. 1 Watt carbon film,  2 Watt Metal Oxide?

Voilà the list of capacitors, followed by resistors. On the left what is stated in the manual with the voltage from the actual component, if I could see it. Most of the paper caps are 400 volts, some are 200 volts. On the right what I could get in the shop (radial components if possible), also voltage-wise.  Could not find Y-caps on their site... 

CAPACITORS
3 .05 mf 50 nF / ?V -> 47nF / 400V
11 4 mfd 4 uF / 350V -> 10uF / 450V
11A 8 mfd 8 uF / 475V -> 10uF / 450V
14 .1 mf 100 nF / 400V -> 100nF / 400V
24 .01 mf 10 nF / 200V -> 10nF / 400V
28 .015 mf 15 nF / 200V -> 22nF / 400V
30 .1 mf 100nF / ?V -> 100nF / 400V
34 .015 mf 15 nF / 400V -> 22nF / 400V
37 .003 mf 3 nF / ?V -> 3,3nF / 400V (not axial)
38 .006 mf 6 nF / 400V -> 6,8nF / 400V (not axial)
40 .008 mf 8 nF / 400V -> 8,2nF / 250V or 7,5nF/1600V (not axial)
45 25 uF 25 uF / 475V -> 33uF / 450V
47 .015 mf 15 nF / Y-cap -> as above, i.e. 22nF 400V?

RESISTORS
12 10.000 ohms (3 watt) -> 10k / 3W
15 1.0 meg (1/4 watt) ->1M / 0,25W
16 10.000 mmf (1 watt) ->10k / 1W
21 490.000 ohms (1/2 watt) ->490k / 0,5W
22 51.000 ohms (1 watt) ->51k / 1W
27 1 meg (1/2 watt) ->1M / 0,5W
31 1 meg (1/2 watt) ->1M / 0,5W
33 1 meg (1/2 watt) ->1M / 0,5W
35 1 meg (1/2 watt) ->1M / 0,5W
36 99.000 mf (1/2 watt) ->100k ?? / 0,5W


Messages In This Thread
RE: Philco Model 38-7: what caps & resistors do fail typically? - by Musaeum - 06-20-2025, 12:27 PM



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