CR216 project

[TC Chris]

My 1951 (???) Wedgwood Maggie is a project at the cottage, where it lives.I'll be recapping it. The last time it operated, maybe 30 years ago, it was motor-boating unless the bass was turned all the way down, suggesting cap failure.

My notion is to recap it here instead of hauling all its parts--chassis, speaker, antenna--home with me. So before leaving home I got out my service info and listed the paper and electrolytic caps I'd need, and selected what I needed--except for the electrolytics, which did not match the value in my stash. Unfortunately I probably won't be back here until mid-March when boat-maintenance season starts. At least that will give time for cap ordering

Then tonight I started matching the capacitor numbers and values on my printed paper one and an online copy. Neither is very good but they are bad in different places, so I could mostly identify the principal ones. These caps, or at least many of them, were the old flat ones with colored dots for values. I brought along my book of color codes for caps and resistors so I will be able to verify that this is, in fact, cap 52, ,02 mfd.

This chassis has 3 cathode bypass caps. My plan is to replace all the electrolytics since they've all reached the age of 74. They ere not humming when last operated but that was 30 years ago.

All that staring at tiny numbers put me in a bit of a mood so I'll maybe start tomorrow on the actual replacing.

I've become a fan of cutting the leads on the old component long, and soldering the new component to the old leads instead of unsoldering the old leads at their terminals--tube and control lugs, etc. Often the old leads were securely wrapped, and getting them both unsoldered and detached caused lug damage. The approach depends on the location. Sometimes it's easy to detach the original.

Chris Campbell

[electra225]

Cutting the leads long, then attaching new caps to those is "officially" called "hook and loop". RCA built a TV chassis that had the tubes sticking thru the back side of the chassis. It was nearly impossible to access the "front" side of the chassis, so RCA actually instructed in their service literature to use the hook and loop method when replacing capacitors. My stepdad had a TV repair shop, and taught me to replace caps that way. Advancing age causes hands to be less steady, so hook and loop can prevent damage to tube sockets.....

Keep us informed of progress on this project, Chris. That ought to be a dandy rig once you get it all recapped and sorted.

[stbasil]

Or, sometimes I just clip the old lead flush with it's attachment, then wrap/tack the new lead to the terminal. Yeah, that sometimes fattens up the terminal with extra wire, but it works! I just suppress my feelings of guilt doing it that way

[TC Chris]

I have a Radio Shack desoldering device. It has a suction squeeze bulb to suck of old solder. When appropriate, it works very well to allow removal from terminals. But sometimes "hook and loop" is just a lot more convenient and effective.

Chris Campbell

[TC Chris]

The only progress I made was trying to ID the cap numbers and values shown on the schematic. One way is by matching the part number with the value from the parts list, which is fully legible. Usually either the part no. or the value would be semi-legible. In addition, I was using an online schematic, marginally more legible, to verify. Between the parts list, the paper print-out schematic, and the online one enlarged, I was able to ID most of the larger-value paper caps and the electrolytics.

Then life intervened, with family & friends visits, which are more valuable, in the long run. Wish I were closer by to get things done right away, but as a college roommate often said, "If wishes were horses, beggars would ride." At least I'll have time to order up the electroluytics. I always buy extras so as to improve my on-hand stash. But wouldn't you know, Magnavox chose values that were not on hand.

Nobody can see me grinning right now. Long ago I had photocopied a Sams schematic for this device. I could not find it before the recent trip so all I had was the blurry schematic I had printed from an online source. As I was typing this, my brain made the connection: that schematic is in the binder I made for my various Maggies. It sits next to the desk where I'm typing. Sure enough, there it is, and it is fully legible.

It's on the old coated copier paper--remember that? I got it from the U-M Engineering Library, which was upstairs from where I had a campus job in the Undergraduate Library (UGLI, as it was fondly known). When I had spare nickels in my pocket, I'd head upstairs and copy schematics. Five cents a copy at the machine. Strange as it sounds now, sometimes there were not spare nickels. This one required several sheets taped together.

Chris Campbell

[TC Chris]

Took my legible schematic, the one on old coated paper, to my office today and copied it. Modern copiers are remarkably good (although our latest one was not engineered by people who have ever used a copier). The copy was almost identical to the original. I like to work with copies so I can mark on them, trace circuits, etc.

But the machine.... I made a copy of the first half of the schematic and it came out fine. Flipped the original for the second half, and I got a "no paper in drawer 4" notice. OK, that happens, so I grabbed a package of paper, ripped off the covering, opened drawer 4, and it was... full already. WTF? So I closed the drawer and hit "copy" again and it churned out the 2nd half. I'm beginning to think that the machine has an AI component that has ;earned to exasperate its human companions.

Chris Campbell