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Philco 645 Hum-m-m-m
#9

Prior to applying power, I replaced all electrolytics, paper caps (tubular and Bakelite blocks), and any questionable resistors; checked every coil including the speaker for continuity and appropriate resistance; and tested all tubes for transconductance and emissions.

I believe I have wired everything correctly, but (you may find this hard to believe) I have actually made mistakes in the past. I can read a schematic pretty well, but when I get befuddled I resort to sketches.

[Image: https://lh5.googleusercontent.com/-r8rVl...520645.JPG]

The BC resistor and condensers 58, 59 were particularly troubling because the condensers has been replaced with a couple of cardboard electrolytics under the chassis, so the physical wiring was changed from the original. I also wasn't sure which end of the resistor was +, -, B, or C. I rebuilt new cans for 58 & 59, and rebuilt the 3-condenser can.

This is a before/after comparison. All replacement components are reproductions.

[Image: https://lh6.googleusercontent.com/-ihp5d...520645.jpg]

The power resistor has three terminals. On this picture, numbering the terminals from left to right as 1, 2, and 3; can you give me a designation for each terminal? I think I connected the middle one as C-. As for C58 and C59: I think the negatives are connected to the BC resistor and the positives to opposite ends of the field coil. The Philco schematic doesn't indicate (+) and (-) on the electrolytics.

I have to pull the chassis again, then start verifying my connections and check that I don't have any reversed polarities on the electrolytics.

Thanks for the help. It'll take me a few days to check out everything you've mentioned.


Messages In This Thread
Philco 645 Hum-m-m-m - by Winky Dink - 04-07-2014, 08:21 PM
RE: Philco 645 Hum-m-m-m - by gregb - 04-07-2014, 08:24 PM
RE: Philco 645 Hum-m-m-m - by Warren - 04-07-2014, 09:05 PM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 04-07-2014, 09:23 PM
RE: Philco 645 Hum-m-m-m - by Ron Ramirez - 04-08-2014, 05:31 AM
RE: Philco 645 Hum-m-m-m - by morzh - 04-08-2014, 10:10 AM
RE: Philco 645 Hum-m-m-m - by PAradiogeek - 04-08-2014, 11:16 AM
RE: Philco 645 Hum-m-m-m - by TA Forbes - 04-08-2014, 01:26 PM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 04-09-2014, 12:54 AM
RE: Philco 645 Hum-m-m-m - by TA Forbes - 04-09-2014, 10:58 AM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 04-09-2014, 01:45 PM
RE: Philco 645 Hum-m-m Fixed? - by Winky Dink - 04-12-2014, 10:43 AM
RE: Philco 645 Hum-m-m-m - by Steve Davis - 04-12-2014, 11:36 AM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 04-12-2014, 11:57 AM
RE: Philco 645 Hum-m-m-m - by TA Forbes - 04-12-2014, 12:04 PM
RE: Philco 645 Hum-m-m-m - by BrendaAnnD - 04-12-2014, 04:18 PM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 04-13-2014, 05:14 AM
RE: Philco 645 Hum-m-m-m - by morzh - 04-13-2014, 09:28 PM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 04-14-2014, 01:29 AM
RE: Philco 645 Hum-m-m-m - by morzh - 04-14-2014, 08:23 PM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 04-16-2014, 04:28 AM
RE: Philco 645 Hum-m-m-m - by morzh - 04-16-2014, 10:30 AM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 04-16-2014, 04:24 PM
RE: Philco 645 Hum-m-m-m - by TA Forbes - 04-16-2014, 04:43 PM
RE: Philco 645 Hum-m-m-m - by morzh - 04-16-2014, 05:05 PM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 04-17-2014, 04:54 AM
RE: Philco 645 Hum-m-m-m - by morzh - 04-17-2014, 08:54 AM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 04-18-2014, 01:08 AM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 07-02-2014, 11:20 PM
RE: Philco 645 Hum-m-m-m - by Arran - 07-03-2014, 12:21 AM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 07-03-2014, 01:53 AM
RE: Philco 645 Hum-m-m-m - by morzh - 07-03-2014, 09:45 AM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 07-04-2014, 12:37 AM
RE: Philco 645 Hum-m-m-m - by morzh - 07-05-2014, 11:09 PM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 07-06-2014, 01:57 AM
RE: Philco 645 Hum-m-m-m - by morzh - 07-06-2014, 08:58 AM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 07-06-2014, 09:30 AM
RE: Philco 645 Hum-m-m-m - by morzh - 07-06-2014, 10:16 AM
RE: Philco 645 Hum-m-m-m - by Winky Dink - 07-07-2014, 08:04 PM



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