I have a wirewound resistor in my Philco 640 (P/N 33-3208, #78 in the schematic) . It is listed as 60 ohms and 100 ohms. It's pretty cruddy looking and even if it tests good I would like to replace it. I checked Chuck's site and some Philco part catalogs I've found on the internet but can't find any information on wattage. What would you guys recommend? Schematic is attached.
(05-18-2016, 08:02 PM)Geoff Wrote: Thanks Morzh. Where did you get your information? Do you have a scanned Philco parts book that you could share?
No. I just figured that would do.
IIfthe current draw of the whole thing is 100mA (and it is a lot) then the dissipated power of the 100 ohms is 1W and 60 ohm - 0.6W respectively. Double that for margin.
If you want to have more margin, then 3 and 2 Watts respectively.
Ps. Agree with others - very nice looking resistir, why do you not like it?
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.
I tested it and the 60 ohm section was fine but the 100 ohm tested at 117 ohms. Still within a 20% tolerance but I don't want to have to deal with it later on down the line if it becomes an issue.
I know some of you guys don't like to hear this but when I repair a radio I tend to use the "shotgun" approach for resistors and paper capacitors, replacing all of them. Mainly because I do not want to have to dig back into a set once it is fixed but also, to properly test most resistors you need to unsolder one end. Since I'm half way there already I just follow through and unsolder the other end.
Please don't beat me up too much on this approach guys .
(This post was last modified: 05-20-2016, 02:43 PM by Geoff.)
As it is your radio it is your right to do to as you see fit. Send me all of the old caps and wire wound resistors, I can use them for my detailed restorations.
Gregb
(This post was last modified: 05-20-2016, 06:15 PM by gregb.)
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