[morzh]

The restuffed caps.

   

[KCMike]

Looking good Mike

[morzh]

Forgot the tone control.
Took me 15 minutes
Ray's book shows 10nF inside (it is a 1-cap type), the schs from our library show 15nF and 20nF.
I went with 15nF.

[morzh]

I realized the rings that I fashioned out of the remaining parts of the caps' cylinders did not center well on the contact ring on the chassis. so I removed them and ordered M22 copper rings with 28mm outer diameter which fit exactly right. After this the contact was good and the rings sit nicely. I cut a little groove for the negative wire soldered between the ring and the base to not skew the ring so it sits flat.

   

[Eliot Ness]

So Mike, is the only purpose of those copper rings to connect the negative of the capacitor to the chassis?

[morzh]

John,

Not to the chassis. The caps' negatives are not directly connected to the chassis; they are connected to the Rectifier negative and then via the bias resistor to the chassis, so the caps rest on the contact rings on top of cardboard washers which insulate the caps from the chassis.

The way I cut the cans makes them to not touch the contact ring anymore. This is why I have to somehow provide the new connection. The copper ring soldered to the cap's negative wire does exactly that, pressing against the contact ring.

[Ron Ramirez]

Great job, Mike. Where did you get those copper washers? I think I want to do that the next time I attempt to rebuild a Mershon or Sprague electrolytic.

[morzh]

They are sold on both eBay and Amazon.


HIFROM 25pcs M22 Copper Washers Flat Ring Sump Plug Oil Seal Gasket Sealing Fitting Washers

https://www.amazon.com/HIFROM-Copper-Was...204&sr=8-1

Those are M22 with 28mm outer. The 22mm hole is exact fitm

However I would increase the outer by another 2mm making it M22x30. But so far most ones are 22x28. Or 22x39 which is way too much. Then again 22x28 work just fine.


PS. Oh...and I had to remove both rippled and flat washers from under the nut that goes to hold the positive bolt: they got too close to the nut holding the cap to the chassis.

[morzh]

I extracted the second RF xfmr from the donor chassis to install and saw the dreaded green...the meter confirmed an open winding.
I rewound it and am waiting for the glue to dry over and form the film before i solder the ends and install the coil in the shield.

[morzh]

First I put the rewound coil back.

   

Second, as I remembered from  my 70 and 90 before, putting back the tuning cap is low fun.
Have to keep the cap aligned while pressing upon it to keep the grommets in place: mine are two-piece type so they don't stay put without much coercing.
Also pressing the screws using a regular socket didn't work well as the socket is deeper than needed, so I put a hex screw inside the socket thread first and the head made the socket shallow.
Anyways. It is back in its place.

Now is the time to check the tubes, find a working speaker and try to power up.

[morzh]

Checked the fubes; all are good. I replaced the 80 rectifier tube as I have a few and this one was a bit in the "?" territory.

The power switch was open after 20 clicks, so I used Trolmaster. The thread is different so it could only catch half a thread but it locked. I used Deoxit D (red) contact cleaner. Most of it escaped but what little penetrated did the job and the switch worked on the first try and then on every click.

The speaker, as I stated before, has bad transformer.
I have two working speakers, one 20 and one 90 SE so I used the latter. It has some cone repar or separation but I figured it would work.

   


So, I powered it up, the voltage climbed nicely, and in 20 seconds I was listening to the Jersey Shore radio.

Now the speaker repair and alugnment.

[morzh]

Today I took the baffle board out, and took the speaker off.
As I said before, the transformer is bad. I happened to have a 90 xfmr for a single 47 tube output, but its lug base board is missing one lug and one is damaged, so I intend to try to swap it with the existing transforner which is bad but has good lug board.
Then I will put the xfmr to the speaker (boy it is involved) and change the wiring.
Then put back the speaker, grillcloth and all if it back in the radio.

Qs:

1. Do I use the regular grillcloth for 20/70/90? It is different from that golden cloth but if this is the closest then....sure. Or is there a better match?
2. The sunk holes for the screws holding the speaker are under the cloth and the screws are not imbedded, they are supposed to be held and tightened by a screwdriver. So, this means the speaker has to be mount before the grillcloth goes on. With the speaker attached this is, to put it mildly, extremely inconvenient.
Has anyone done it and are there any tricks?

[morzh]

I realized the speaker is not from 70. 
The dead transformer is 2766 which is a pushpull, probably from 90. It is not a 20 speaker as the pole is pressed, not the one with a nut.
I just happened to have 2673 transformer, the one from 47 output 70 I bought many years ago from Gary Scneider for very little m9ney.
So I grafted it in.
It is little fun doing this, but...

   
   

I opened the plug by using cutters and mushing the rivets and pulling them
Then when assembled, i put glue in the holes of the face part and put the rivets back. Hopefully the will catch.

   

[morzh]

This is not the fitst time I encounter it but this time it is very pronounced:

The dial gear on 70 barely engages. There is a spring that, I take it, pushes the gear friction barrel with the groove against the edge of the giding channel of the dial.
What are the easiest ways to make it move better?
BTW the cap even after wash and lube is kinda tight so this exascerbate the issue.

Taking out the spring is kinda out of question: I don't eant to grind the riveys and then re-rivet the bracket that holds the tuning shaft. I slid the dial over the cap's shaft such that the guiding channel presses against one of the groove's sides but it is not enough for reliable rotation.

PS. The speaker plug glued nicely and Trolmaster with F5 Deoxit worked the magic on the volume control.
If it weren't for the gear I'd start the alignment.

[KCMike]

Mike as I recall they are a pain to get back in the groove. That spring has good amount of tension.
I had to spread the slot with screw drive while sliding the dial scale bottom edge into it at same time lining up the center dial scale hole to tuner shaft.