[morzh]

Arran

No, I have never rewound a shadograph. I would have to come up with some mechanical contraption as to do it manually is totally not worth the 50 bucks I paid for the one I asked Alabama Dave to do. It was for the Philco 18 and it was 3 years ago.
I got lucky with 118 I fixed a couple of months ago, the shadow graph worked.

Well, I have two things magnetic to do: the speaker to re-cone and the shadograph.

I am chugging along with the recapping, it is all screwed up with the tubular caps all over the place plus discrepancies with the schematic made while someone repaired it in the very remote past.
The major nasty left is the capacitor can which is a lot like the 20's and that was a pain every time.

[morzh]

Today:

While extracting the capacitor can, decided to check the wirewound pot on the back panel, the one from AVC circuit.
It is open. Ordered a similar from eBay, cheap, $1.50 from China. If doesnt fit, it's a dollar-fifty.

So the whole bias network did not work.
Also fully open 100K resistor in the 1st AF, 77 tube plate circuit. Wouldn't work.
Wow, this radio is one handicapped old-timer.

[morzh]

Yesterday night I mustered up all my courage and attacked the capacitor can.

The 16's can is the most hated type (by me), same as the 20's one. It is narrow and deep, and this makes for very inconvenient extraction.
I separated the cardboard from the tin as much as I could, by squeezing the sides and running a flat thin screwdriver between them, and tried to shake the contents out. To my surprise I saw the movement, which was a good sign.

Then I put a corkscrew with wooden handle in; this somewhat expanded the contents, but then I used the thick metal vertical piece that bolts the can to the side of the chassis as the lever against the corkscrew handle, using large vice as the fulcrum, while heating the can with the Milwaukee gun. This pulled the contents about 1/2", then the caps inside separated and I was able to extract the whole thing without much mess at all.

Got lucky.

I had the plate with the new caps already assembled, put it together, soldered the ground wire to the can, and voila! - the can was done in 1/2 hr (yes, took me about that much to figure out what to do).

One small step for this radio, and a huge relief for me

[morzh]

Once more the rule is confirned. Large dogbones, which I have two, lose resistance instead of gaining it. Both 13Kand 15K became 10K ones. Well, I bought a bunch of 5W of all the needed values, so I was prepared for that.

[morzh]

Well, this was fast. The 10K wirewound trimpot came from China.

http://www.ebay.com/itm/172350624604?_tr...EBIDX%3AIT


$1.33. Free shipping. How do they do that.....

It's a bit larger than the original but did fit fine.

I also have rebuilt the electrolytics and tonight installed them and the trimpot.
In short, I am done with recap/recarb.

Need to install the tuning cap back.

Then

1. Send the speaker for the recone.
2. Send the shadowmeter for rewind.
3. Check the power xfmr integrity.
4. Check RF coils.

It does not move superfast but then I am a bit busier with my schedule, having return (together with my son) to brazilian jiu jitsu training, plus taking him for guitar lessons, so less time to be in the basement.

Anyways. That's where I am right now.

[morzh]

Has anyone encountered this: the resistor #27 that is a 50K part 4237, is replaced with a Philco dogbone, seens factory, white-red (not sure what the dot is), ohms at 22K. This is the oscillator load resistor. Cannot find anything in changes/mids.

Otherwise went through the rest of the resistors, except one all are fine, so done with that.
Sent the speaker out for re-coning.

Will try to replace the tuning cap tonite or tomorrow.

[KCMike]

 Looks like you are making good progress.
I have a 16B chassis I recapped months ago and its waiting on me to finish the cabinet. I'll check to see what resistor I have in that spot.

[morzh]

Thanks Mike.

Otherwise the tuning cap is back in its place and the close-up photos I took helped in remembering where the wires went.
Now waiting on the speaker. I could possibly use another but not sure if I have any. No rush though.

[KCMike]

I checked the 16B chassis this morning. Its different than yours. I have a code 125 version.
The resistor in question on mine is #37 coming off the plate of oscillator and is 10,000K. ...#27 on mine is listed as
a compensating condenser. I used the info I got from Chuck Schwark.

[morzh]

Mike

Thanks.
Yes in your case it is #37 and is 10K.
Mine is, according to Ron, 121 and it lists the same 50K as the Version zero sch has. For whatever readon it was replaced with a Philco resistor of a different value.
Well I guess if it works it works.

[morzh]

Tested the toobs after fixing the Hickok 600A tester.
Have one somewhat weak 77, one really weak 78 and one fully bad 78 with filament open; the rest tested like new or close.

[morzh]

Today the speaker came from Rich Stamer.
I am yet to find out how it sounds but as for the looks, from the cone side it looks like it was bought yesterday.
Came packed like it should be.
Great job.

Connected it, just now. If I have an extra 78 tube, I might fire it up tomorrow, if not, will order it and then do it.
Dee called with my shadograph; there is some light problem with the vane, he said it gets stuck when going all the way to the corner, promised to fix it.

Reassembled the tuning cap gear. The first wheel I was able to take the tire of, though with some elbow grease; the second, the larger one, proved very entransigent, and I soaked it in mineral spirit and forgot about it for two weeks. Today remembered; the remnants of the tire came off easily, and I cleaned the knurled part with a stiff steel brush. Put the O-rings on, seems to work. Will have to wait 'till the shadograph comes it to complete the assembly.

[morzh]

Meantime, I decided to fire the radio up. With 80 tube in place of 5Z3. First I measured the HV transformer output, was fine, so I inserted the 80 in, checked the B+, was fine, let it warm up, touched the 1st AF grid, heard the buzz, tuned the BC band into the local station; first nothing, then I remember the AVC switch, flipped it,....the station came through. Not as strong as I expected, though with a short screwdriver touching the antenna clip it became very loud.

Well, maybe it will be it for today....perhaps I will order the 5Z3.

[morzh]

Now that I saw that the 80 is the tube for it, I will leave it in. Boy does it get hot: this one is the small cylindrical envelope ny Ratheon and I seared my fingers a bit trying to take it out.

The speaker sounds beautifully, thanks Rich!

Now the only band I hear is the BC, the other two are silent.
Another thing, the AC hum. I checked it and could see the wire connecting the wiper of the volume pot to the output cap is picking up the hum as I move my hand near it. Could be due to the increased value of the pot. I think I will try shielded wire. And the wire runs exactly where it did before, so no new influences. Shielding might help.

Will see later.

[morzh]

The bands, as it happened, were not silent, just needed a short piece of wire for an antenna.
The police band is silent but there is a reaction to the antenna, so I think the hardware is fine. Just nothing to listen to.

The hum is persisting. It fully disappears when I ground the chassis.
It is picked up from the detector output but I cannot blame any particular part: it simply is a high input resistance of the first audio stage, so if you leave any wire hanging or move your hand near that connection (the detector out and a bunch of resistors) or the wire, then the hum intensifies.
I put the 1st audio input (well, the long wire from the vol reg wiper) in a shield and grounded it, the hum barely subsided.
I wrapped the 0.01uF cap that goes to the upper pin of the vol reg in the foil and grounded it, it reduced the hum a bit.
I moved the AC power wire away from the connection, it did not help. I even unsoldered it from the power switch and removed it altogether, same result.
The hum is heard when there is no reception and the volume is sufficiently high. Still would like for it to go away.

So, a couple of questions:

1. Those of you who have this version of 16, 121/122 with the 2M volume pot (not the 330K one) or who have done the modification according to the instructions: do you have any hum like this or not?

2. The dial seems to have 5 bands. The sch shows 5-pos switch. But the switch only seems to have 4 positions. Or am I missing something? Probably I am....but I could only switch 3 times.