[R-1051] Oven Bridge Resistor

[Steve Hobensack]

Thanks Bruce. I have that schematic. I should have mentioned that. I believe it is a special resistor even though it shows 3.9k 1% tolerance. I tried an ordinary carbon resistor of that description and it doesn't work in that the current to the oven resistor will not drop
down when 85C degrees is reached while adjusting the temp trim pot as it does on my other oven. I am wondering if the 3.9k is the cold 
resistance or the hot 85C resistance.
Steve N8YE
 

> From: ligature at burlingtontelecom.net
> Date: Tue, 27 Mar 2012 15:24:15 -0400
> To: r-1051 at mailman.qth.net
> Subject: Re: [R-1051] Oven Bridge Resistor
> 
> The schematic on the B variant shows it as a 3.9k + - 1% resistor, in a bridge circuit with R13, 14, 15 & R16.
> Bruce
> 
> 
> On Mar 27, 2012, at 8:45 AM, Steve Hobensack wrote:
> 
> > 
> > I am trying to repair the oven bridge resistor mounted on the underside of the oven on the frequency standard module. I removed the plastic foam with a drimmel wheel. The resistor is cooked, and split open. It is a wire wound resistor using extremely fine wire. Is this resistor a thermistor? What is the cold resistance? I cannot measure because the fine wire is destroyed. This resistance can be found by pulling the crystal board from the oven . There is a 5 prong connector at the bottom of the oven cavity. Pin 5 is 5 MHz output, 4 is 28vdc, 2 is the top end of the oven heater wire. The bridge resistor is between prong 3 (middle) and chassis ground pin 1.
> > Thanks
> > Steve N8YE 
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