Posts: 668
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Joined: Jun 2011
City: Elko,MN.
Hi guy's,
Have a question regarding values of dog bone resistors.
Working on a Grunow 654 and it has 2 dog bone resistors.
Schematics calls for a 5M ohm resistor and a 20M ohm resistor.
Does not specify how many watt resistors these are.
I think most other resistors in this unit are 1/2 watt.
Not sure about these.
Any suggestions?
murf
Posts: 2,128
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Joined: Oct 2008
City: Merrick, Long Island, NY
Sounds like 5000 and 20,000 ohms, my best guess. If in the voltage divider circuit, could need 2 or more watts. Need you to post scematic or link to be sure. Of course one would like to fix or define underlying cause for failure. Measure out of circuit and tell us about it.
Posts: 668
Threads: 144
Joined: Jun 2011
City: Elko,MN.
Thanks for the reply Codefox,
Schematics for this radio can be found on nostalgia radio free schematics.
It's a grunow model 654.
One of these is connected to a tube socket and the other is connected to one of the electrolitic circuits.
They are reading a little high.
One is reading about 7M instead if 5M, and the other is reading about 25M instead of 20M.
I wonder why some schematics specify wattage, and others don't?
Thanks
Posts: 1,703
Threads: 55
Joined: Sep 2005
City: Evanston, IL
Murf,
Guess you have not browsed my Philco website enough?
From the PARTS VALUES section, under resistors:
http://philcorepairbench.com/resistcompare.htm
Comparison pics of typical dogbone types and wattages shown by physical size.
[Image:
http://www.philcorepairbench.com/images/carbon01.jpg]
[Image:
http://www.philcorepairbench.com/images/dogbone01.jpg]
[Image:
http://www.philcorepairbench.com/images/dogbone02.jpg]
Chuck
Chuck
Posts: 668
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Joined: Jun 2011
City: Elko,MN.
Excellent info.
I will print this page out for my records.
Thanks
Posts: 1,703
Threads: 55
Joined: Sep 2005
City: Evanston, IL
Murf,
Look thru all the Service Tips. Lotsa good stuff.
Chuck
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
Might add that most dogbones are past their best used by woof. Not everybody would agree though.