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 Post subject: Double check this resistor for me please
PostPosted: Jan Tue 23, 2018 4:12 am 
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I am reasonably sure that the component circled below is a resistor, but I would like to be sure.
The radio is a Zenith 6D414, the schematic is here; http://www.nostalgiaair.org/pagesbymode ... 025083.pdf

Using the Body-End-Dot method of ID, and depending on what color the body is (red or orange), I would judge this to be either a 290K ohm or a 390K ohm resistor. Actual resistance measured is 296K.
According to the parts list, there is not a 290K or 390K resistor in the radio. One end is connected to C9, and the other end goes to the shield of IF transformer 2. It makes me think that possibly it is a replacement, and that perhaps it is R12. R12 is listed as a 220 K ohm resistor in the parts list.

For the heck of it I measured it with my el-cheapo LCR meter which thought it was a 1.8uf capacitor with an ESR of 55 Ohms. I still believe it to be a resistor though, just a different package than the others in this radio (dog bones).

Thanks!

Russ


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 Post subject: Re: Double check this resistor for me please
PostPosted: Jan Tue 23, 2018 4:57 am 
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It's probably been replaced in the past, if that's where it's connected then it can only be R12 since there shouldn't be any other resistor connected to the metal parts.

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 Post subject: Re: Double check this resistor for me please
PostPosted: Jan Tue 23, 2018 5:07 am 
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radioalfa wrote:
R12 is listed as a 220 K ohm resistor in the parts list.
Hi Russ,

This demonstrates the exact problem that caused B-E-D coding to fall out of favor.

The two significant digits are the Body (1st digit) and the End (2nd digit).

With 220K, the Body and the End are the same color... RED.
The Dot (multiplier) should be YEL.

- Leigh

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 Post subject: Re: Double check this resistor for me please
PostPosted: Jan Tue 23, 2018 5:13 pm 
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Thank you both!

Russ

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 Post subject: Re: Double check this resistor for me please
PostPosted: Jan Tue 23, 2018 10:06 pm 
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I have seen that type of resistor before in Zenith sets; they tend to drift upward in value

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 Post subject: Re: Double check this resistor for me please
PostPosted: Jan Thu 25, 2018 6:17 pm 
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Tim Tress wrote:
I have seen that type of resistor before in Zenith sets; they tend to drift upward in value


That seems to confirm my measurements then. One other observation, all other resistors with the exception of a more modern replacement are dog bones, perhaps this was a replacement.

Russ

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 Post subject: Re: Double check this resistor for me please
PostPosted: Jan Thu 25, 2018 6:39 pm 
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radioalfa wrote:
...perhaps this was a replacement.

The three disc ceramics with their leads twisted together are not original either.

- Leigh

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 Post subject: Re: Double check this resistor for me please
PostPosted: Jan Fri 26, 2018 1:33 pm 
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Thanks Leigh, yep those caps are on their way out along with the paper caps and many if not all of the resistors; except for R9 which I'll be darned if I can find.

Russ

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 Post subject: Re: Double check this resistor for me please
PostPosted: Jan Sat 27, 2018 1:55 pm 
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Considering the volume of radios that Zenith was producing at the time (over 900,000 for the 1940 model year), they probably used whatever components they could get without delaying production. It's not uncommon to see a mix of dogbones, Bradley type, and other resistors in their sets, even in the early postwar production.

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