37-630 Filter caps 60 and 62 backwards on schematic? - Printable Version
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+--- Thread: 37-630 Filter caps 60 and 62 backwards on schematic? (/showthread.php?tid=18715)
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+--- Thread: 37-630 Filter caps 60 and 62 backwards on schematic? (/showthread.php?tid=18715)
37-630 Filter caps 60 and 62 backwards on schematic? - harleythatcher - 07-19-2018
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.
RE: 37-630 Filter caps 60 and 62 backwards on schematic? - morzh - 07-19-2018
Their sch are in dejavu format; not everyone could see it.
Judging by 620 here
http://www.nostalgiaair.org/pagesbymodel/212/M0013212.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.
RE: 37-630 Filter caps 60 and 62 backwards on schematic? - harleythatcher - 07-19-2018
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
RE: 37-630 Filter caps 60 and 62 backwards on schematic? - morzh - 07-19-2018
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).
RE: 37-630 Filter caps 60 and 62 backwards on schematic? - harleythatcher - 07-19-2018
Yep it's been awhile but that sounds about right. TKs and I appreciate your time.
Tt