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 Post subject: Philco 90 pp 47
PostPosted: Dec Mon 05, 2022 2:20 pm 
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Joined: Sep Mon 17, 2007 11:52 pm
Posts: 22
Location: Fort Wayne, Indiana 46825
The wirewound resistor (4 sections - 205, 95, 2400, 1200 ohms) part number 6071. The question is: For this application,
are 10 watt wirewound resistors sufficient to replace this?

Dan Waldschmidt
(469) 785-8105
dwaldschmidt757@gmail.com
Fort Wayne, IN


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 Post subject: Re: Philco 90 pp 47
PostPosted: Dec Mon 05, 2022 2:54 pm 
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Location: Phoenix, AZ
buster757 wrote:
The wirewound resistor (4 sections - 205, 95, 2400, 1200 ohms) part number 6071. The question is: For this application, are 10 watt wirewound resistors sufficient to replace this?
It is not a simple answer because each resistor actually dissipated a different amount of power. It was one big resistor because it was all in the same assembly, but if you replace it you are probably putting in 4 separate resistors and they do not all need to be the same rating.

So, let me ask a question. Is the radio now running with the original resistor in place? If so make voltage readings across the terminals for each specific resistor and determine exactly what is required for each one.

The equation for power = (V x V)/R then you multiply by 2 for a safety margin.

So for example if there was 10 volts across the 95 Ohm resistor this becomes...

(10 x 10)/95 = 1 Watt, then double this to 2W and that's what you buy.

Curtis Eickerman

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 Post subject: Re: Philco 90 pp 47
PostPosted: Dec Mon 05, 2022 3:00 pm 
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Joined: Sep Mon 17, 2007 11:52 pm
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Location: Fort Wayne, Indiana 46825
I understand the formula, but going high on the wattage can never hurt anything. I have some 10 watt resistors of the exact resistance. So those should be fine, right?


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 Post subject: Re: Philco 90 pp 47
PostPosted: Dec Mon 05, 2022 3:16 pm 
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Location: Gretna, Nebraska
buster757 wrote:
I understand the formula, but going high on the wattage can never hurt anything. I have some 10 watt resistors of the exact resistance. So those should be fine, right?


Normally, that would be fine, and if you have the space under the chassis it doesn't hurt anything to use the larger wattage resistors.

I say normally, because in small number of applications, the resistor may be intended to act as a fuse, and the wattage rating then becomes an issue. With this radio, I do not think this applies.

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Paul
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 Post subject: Re: Philco 90 pp 47
PostPosted: Dec Wed 07, 2022 8:15 am 
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Location: 253 Blanche St. Plymouth, MI
buster757 wrote:
I understand the formula, but going high on the wattage can never hurt anything. I have some 10 watt resistors of the exact resistance. So those should be fine, right?


Answer is YES 10 watts is enough for that resistor set. In fact, the smaller sections can be 3 or 5 watts as I recall.

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Mark Oppat
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