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THE AM BULLETIN BOARD => Technical Forum => Topic started by: wb6kwt on June 21, 2011, 07:46:17 PM



Title: What type of caps are these?
Post by: wb6kwt on June 21, 2011, 07:46:17 PM
I'm trying to get a Globe Champ 350 up and running and came across caps in the VFO parts list, marked TCN and TCZ, any idea what those designators mean?

Thanks,

Bob



Title: Re: What type of caps are these?
Post by: w3jn on June 21, 2011, 10:45:30 PM
Most likely temperature compensation caps.  TCN probably is a negative temp coefficient (ie N750 in today's parlance) , TCZ is probably zero coefficient (NP0).


Title: Re: What type of caps are these?
Post by: KA2DZT on June 22, 2011, 03:14:46 AM
W3JN is probably right although I've never seen those designators that I can remember.

Usually temperature compensation type caps are disc ceramics.

Are the caps disc ceramic??  Are the designators on the caps or are you reading them from a parts list??

Answer to my own question, your post states the VFO parts list.

The caps should be marked with the negative temp coefficient number.  There are more than just N750.

Unless the VFO is drifting too much I would just leave those caps as is.

Fred


Title: Re: What type of caps are these?
Post by: KM1H on June 22, 2011, 03:55:28 PM
TC caps were initially tubular (or sealed to appear solid) dogbone ceramics and were available fom 0 to -5600 and some positve versions also. Discs came along later.



Title: Re: What type of caps are these?
Post by: KA2DZT on June 23, 2011, 01:53:23 AM
TC caps were initially tubular (or sealed to appear solid) dogbone ceramics and were available fom 0 to -5600 and some positve versions also. Discs came along later.



Thanks, I forgot about the dogbone ceramics, I have a lot of those somewhere.

Fred
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