16B Cathedral Braided Ground Help - Printable Version
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+--- Thread: 16B Cathedral Braided Ground Help (/showthread.php?tid=20556)
16B Cathedral Braided Ground Help - Rod Wolfe - 10-21-2019
Hello all, special thanks to Ron for getting my Phorum credentials back in order.
Quick synopsis: I've owned my 16B 5-band Cathedral since 1970s.
May 2010 finally re-capped everything... except Tone Control.
I remember that I could not find the schematic for the tone control system I have, which is 2 caps inside the control cavity
and an additional bakelite with caps. So, I only recapped the bakelite.
Over the years the tone control really was only offering a really bass or really treble sound.
So it was time to finish the job I should have completed ten years ago. This time I found the correct schematic and got to work.
Last week I pulled the control which has two caps in a metal cavity and replaced them.
All seemed well until I got everything back together and noticed I didn't have as much tuner sensitivity as I did before the cap work.
I was playing the radio a couple times over the past week but knew it just wasn't right.
At some point I noticed when I touched my external antenna it made no difference to the reception, and it's never done that before.
So this morning I lugged it over to a work table and dissassembled again.
What I found is that front Tuner Cap braided ground strap became disconnected... from somewhere!
This is the grounded braid nearest the front of the chassis.... right near that darn tone control.
My guess is that when I removed the tone control or when I reinstalled it, I must have distrubed that braided ground.
It still has it's glob of solder attached to the end.
I have checked around the Phorum for any chassis pics that may have been posted with the detail I need to re-attach.
Unfortunately I couldn't find any that might help.
And my own pics that I took before disassebly also do not show where the strap was soldered to a ground point.
Can anyone offer any advice, or old pics you may have taken showing how and where this front braid ground is soldered back on?
If not, any other suggestions on how or where to reattach it to anything that would not adversely affect the tuner signal levels?
Thanks so much in advance for all the help past and present.
RE: 16B Cathedral Braided Ground Help - KCMike - 10-21-2019
Hello. did both ends come off? One end should solder to the head of the tuner cap bolt. I will have to find a picture of mine and see where the other end went.
RE: 16B Cathedral Braided Ground Help - Rod Wolfe - 10-21-2019
Yes, that's it, it came off the bolt!
I removed the tone control assembly again and then I could see exactly what happened!
Thanks so much.
I know I still have my old solder gun in some box somewhere.
Hopefully that should provide enough heat to attach the braid back to the bolt head!
Looks like I'll have to flip the chassis upside down to make it easier and as I recall that wasn't too hard to do.
I haven't needed or asked for help in ten years and this incredible Philco Phorum comes to the rescue in a couple hours.
Thanks again!
RE: 16B Cathedral Braided Ground Help - rfeenstra - 10-21-2019
Here you go! Mike is correct. The braid is soldered to the head of one of the tuner screws. It takes a pretty good amount of heat to get the solder to flow. I use a 260 watt Weller D550. The grounded end goes to the ground terminal right near there.
RE: 16B Cathedral Braided Ground Help - Radioroslyn - 10-21-2019
Hi Rod and Welcome,
I too used a Weller D-550 to resolder the braid to the tuning cap's mounting screws. It's very important that they are connected, without them the cap is floating (no gnd connection). You may want to add a wire to the third screw and connect it to the gnd lug that is riveted lug near it.
It's not a horrible idea the remove the tuning condenser and give it a goood clean mine was filthy! Was having a problem w/ bands 4 and 5 not working @ the bottom end. Have it mostly sorted now.
You may glean some useful information from this thread, both set use the same chassis just the tombstone has a 10" speaker. https://philcoradio.com/phorum/showthread.php?tid=20055
GL
RE: 16B Cathedral Braided Ground Help - rfeenstra - 10-21-2019
My 16B has 3 grounding straps. The one shown, one soldered to the rear screw of the tuning cap, and one on top of the chassis soldered to a ground tab under one of the mounting screws for the filter choke.
RE: 16B Cathedral Braided Ground Help - morzh - 10-23-2019
I put my Weller (a regular 40W soldering iron) on High (close to 800F), unsolder the braid, then take the socket wrench and, having really heated up the bold cap (when all the solder is liquefied) quickly put the wrench over the cap to push the solder off as much as possible (it freezes almost on contact) and re-form the cap, so it can be screwed and unscrewed.
Then after everything is done (cap is cleaned, grommets are replaced) and re-assembled, I put the braid on and solder it using the same temp settings for the iron and lots of Non RoHS (tin-lead) solder.
RE: 16B Cathedral Braided Ground Help - Rod Wolfe - 10-23-2019
Thanks to all for all the replies and additional information on the braided grounds, it was a great help!
RE: 16B Cathedral Braided Ground Help - mikethedruid - 10-23-2019
It is when dealing with things like this especially that I value my old Weller 100 / 140 watt soldering gun. It does these jobs a lot faster than the modern, fancy, low wattage irons. I use it for all my vintage radio soldering work, have for more than a half century now. The low wattage ones are fine for PC board work, I have a Weller station for that too, but for antique radio work, I always use my gun. By the way, I also use a flux I made by dissolving violin rosin in rubbing alcohol It really helps when soldering to sheet metal. Weller still makes these kind of guns. I advise anybody doing a lot of antique radio work to invest in one.
RE: 16B Cathedral Braided Ground Help - Jake Blake - 10-23-2019
" . . . my old Weller 100 / 140 watt soldering gun. It does these jobs a lot faster, . . . "
I've had 3 versions of that gun. The oldest one of the 3 is the best, . . . with the hex-nuts. I know it has to be 55 years old, but if you know how to best tighten them, they will last 2 lifetimes ! The newer one's set screws strip out one way or another.
Like so many other tools, things get cheapened through the years, and they cheapened these Wellers with different set screws that aren't worth a dang.
But I dislike irons also.
RE: 16B Cathedral Braided Ground Help - mikethedruid - 10-23-2019
A quick look on eBay shows that one can buy used Weller guns, both the D550 (240/325 watt) and the S500 (100/140 watts), the old ones with the hex nuts, very reasonably. Either one is good for working on antique radio., the D550 for soldering to sheet metal chassis, and general work if you are careful, and the S500 for general work.