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37-630 Filter caps 60 and 62 backwards on schematic?
harleythatcher
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#1

07-19-2018, 10:16 AM
Working on a 37-630T chassis and noticed the filter caps 60 and 62 seemed backwards on the schematic.  Searched this forum and found thread saying it was in fact incorrect and was corrected in Service Bulletin 251.  Can't find SB 251 to verify.  About to solder new caps in place and want to make sure before committing.  Anyone know for sure?

Not sure how to add link, if successful it will take you to page where 37-630 schematic is.
Thank you

http://www.audiophool.com/Philco.html

Oh! That was easy.  Icon_crazy
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morzh
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#2

07-19-2018, 11:00 AM
Their sch are in dejavu format; not everyone could see it.
Judging by 620 here
http://www.nostalgiaair.org/pagesbymodel...013212.pdf

yes it seem like they flipped the symbols.
But no one in their right mind will not connect the filter cap minus side up anyway.
I restored 620 two years ago, did not even notice that.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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harleythatcher
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#3

07-19-2018, 11:20 AM
Tks Morzh.  What got me concerned and paranoid was I finished up a I think it was a 38-60 and one of the filter caps was properly "backwards"  + to CT so remembering that I began to second guess.  Been many years since I retired from Navy elec job.  It's coming back but it is good to have a source of knowledge here on the forum.  TKs again.
Tt
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morzh
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Posts: 16,266
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#4

07-19-2018, 11:40 AM
No, what you probably are talking about is the cap that in 620 is #68 (though it is not electrolytic here, but in some radio it is).
This cap is always placed with its plus to GND because the other side is the rectifier's negative which is always more negative than the GND (it is in fact the most negative point in the whole radio).
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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harleythatcher
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Posts: 15
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Joined: Apr 2018
City: Pensacola, Florida
#5

07-19-2018, 12:00 PM
Yep it's been awhile but that sounds about right.  TKs and I appreciate your time.
Tt
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