[klondike98]

I'm working on a 60MB that needs a lot of love. 

[Image: https://www.dropbox.com/s/ykqu2clyysskp2....jpg?raw=1]
 
I'm working to get the tuning cap off.  Normally not an problem but has anyone ever seen this before?  There is a wire going from the block cap pin 1 (which is grounded through the mounting screw, highlighted with the orange line) to the tuning cap mounting bolt and soldered to the head of the bolt (orange arrow).  You can see the other two mounting bolts above.  Hopefully I'll be able to get enough of the solder off to get the bold out but sheesh...thoughts?
 
[Image: https://www.dropbox.com/s/vqm0c2wvb0u5yj....jpg?raw=1]

[Ron Ramirez]

Notice the lug on the bakelite block in question is grounded.

The wire ensures the rotor of the tuning condenser is properly grounded.

You may have to resort to desoldering braid to get that solder off, but you don't have to remove all of the solder - just enough to get your 1/4" socket wrench onto the bolt. One trick you can try: Heat the solder, then immediately put your socket wrench on the bolt. This may push enough of the solder out of the way so that you can get the socket on the bolt. Been there, done that...

[morzh]

Seen plenty of that in Philcos.
Was able to use my regular iron, a Weller, with temp upped to 700 or so, works just fine.
Typically the wire is a copper braid.

[klondike98]

OK thanks guys.  Was able to get enough solder off to get socket onto the nut.  Came off OK.  Just had not seen that before. 

[klondike98]

OK, time to start working on this puppy.  Its a little rough but I wanted to see if I could pull it out of the gutter.  There's a top chassis view earlier in the thread and here's the front.

[Image: https://www.dropbox.com/s/13qkd5ezt1ydg3....jpg?raw=1]
 
Soaked the tube shields in Metal Rescue overnight and the rust came off.  They don't look great but the rust is gone.  They seem to have had a gray/green coating originally so I could paint them except for the bottom edge where the shield contacts the shield base.  Thoughts?
 
[Image: https://www.dropbox.com/s/x5pffwfmxkg30s....jpg?raw=1] [Image: https://www.dropbox.com/s/cp7s9lamp8h96p....jpg?raw=1] [Image: https://www.dropbox.com/s/7vzl7m9d2dqypu....jpg?raw=1]
 
To tackle the rust on the chassis I need to take as much as I can off the top of the chassis.  The tuning cap was first after getting the mounting screws out with the advice from Ron and morzh in the previous post. Of course the rubber mounts were no good, although some still were relatively soft, they came apart as the tuner was pulled away from the chassis. Decided to soak the whole tuner in Metal Rescue although I did soak the pilot lamp mounting bracket separately. Still some clean up needed with naval jelly I think.
 
[Image: https://www.dropbox.com/s/7xgdzia5tj04pt....jpg?raw=1] [Image: https://www.dropbox.com/s/sys2wvks1nb69e....jpg?raw=1]

[Ron Ramirez]

Bob

The tube shields were originally tin plated. Don't go the Nucow route and paint them green.

[klondike98]

OK..no paint.

[klondike98]

The speaker cone needs some help. There had been some earlier repairs with scotch tape and what looks like service cement on the surround but there were new tears and missing cone as well.  Carefully pulled off the old scotch tape before starting.  Elmers & water approximately 50/50 to soak the filter paper before applying and then smoothed it out with a Q-tip wet with the glue solution.

[Image: https://www.dropbox.com/s/xy6whqoo8fsafd....jpg?raw=1] [Image: https://www.dropbox.com/s/i3hpabu0lp8255....jpg?raw=1]

Voice coil and transformer ohm out OK.

[George Kirk]

Great job got one too do watching your progress
George Kirk

[klondike98]

Thanks George...be sure to look at Bob Andersen's threads and his youtube videos.

[klondike98]

Been recapping the cap box, electrolytics and bakelite blocks.  The box was pretty straight forward since there was fish paper around the tar block of 5 caps and it all slid right out.  Here's the restuffed can.
[Image: https://www.dropbox.com/s/4sozqy0ppxucmg....jpg?raw=1] [Image: https://www.dropbox.com/s/02rtegr2gfk2dx....jpg?raw=1]

Electrolytics stuffed using the info on Chuck's Philco Repair Bench
[Image: https://www.dropbox.com/s/xaenxlv9at5etg....jpg?raw=1]
[Image: https://www.dropbox.com/s/d6za32ovifsbuo....jpg?raw=1]
[Image: https://www.dropbox.com/s/1ip6l4tajvtja5....jpg?raw=1]

In most cases I'm using morzh's procedure for Bakelite restuffing

Now for the technical question.  (60MB Schematic.) The tube socket and tube shield base for the detector oscillator 6A7 are fastened to the chassis with two rivets.  On the underside you can see a lug also fastened to the rivet on the right.  This should be a ground lug (I think) BUT it is 10 ohms above chassis ground.  The tube shield base is ground, the other rivet is ground so I'm guessing this rivet has some corrosion causing this (lots of corrosion on this set!) 

 Would you drill it out and rivet it again, run a ground wire from someplace else to it or am I missing something?

[Image: https://www.dropbox.com/s/ff15vfupwoiu1z....jpg?raw=1]

[Mondial]

Looks like the ground lug is right next to the mounting screw for the adjacent coil bracket. I would install another ground lug under the mounting screw and then wire the two lugs together. The self tapping screws usually make very good contact to the chassis.

Would not trust the ground through the rivet as the tube socket phenolic compresses, which along with the corrosion results in poor contact.

[klondike98]

Thanks Mondial! I thought that lug should be ground. The bakelite block to the right is grounded on the #1 pin so I'll snake a wire from that pin to the lug rather than add a new lug to the coil mount.

[klondike98]

Here's an example of having to be careful about stuffing the bakelite block caps.  They don't always follow the wiring scheme shown in Service Bulletin No. 289.  In the schematic
 [Image: https://www.dropbox.com/s/fczysxvhrrnqym....jpg?raw=1]
 the bakelite block cap of interest for this discussion is # 33, an 8035-D block.  [Image: https://www.dropbox.com/s/z3iyy5swefh7qx....jpg?raw=1]
Service Bulletin 164A notes that 8035-D is to be replaced with 8035-EU.  If you look up 8035-EU in Service Bulletin 289 it shows two caps (110pf and 0.015uf wired with 110pf in lugs 1 & 3 and the 0.015uF in lugs 1 & 2 (and because its labeled "U", lug 1 is not supposed to be grounded).  However if you look at the schematic for cap#33 above, you see that the 110pf cap is grounded on one end and has the 75 tube plate in common with the 0.015uF cap.  To make this work under the chassis, lug #1 of the block is grounded and the caps are wired with 110pF in 1 & 3 and the 0.015uF cap in 2 & 3.  So....pay attention to the schematics as you stuff these!  I'm sure this is old hat to the veterans but only the second time I've come across it. Just about ready to insert the caps (if you're observant, you'll note I've got the lead to be grounded at lug #1 on the far right...it should go on the left into the block    but I did wire it right when I did it....I think   )...
[Image: https://www.dropbox.com/s/g6g5yvx78ats7f....jpg?raw=1]

[sam]

looking great bob
sam