[Ron Ramirez]

Mondial - thanks, exactly what I needed. I would bet that the coil I am now using came from a 71 or 91 with the old style tuning condenser, which probably had more capacitance than the newer, smaller tuning condenser used on the 91-126.

So...the coil will come out again soon, the tertiary winding (on a separate form mounted inside the main coil form) will be removed, and I'll remove some turns. I can see my having to do this two or three times before I get it to a point where it can be aligned. But I think I would rather go to the extra trouble and do this rather than making the 6A7 conversion at this point.

[Ron Ramirez]

Progress report:

I remove the oscillator coil tonight (again). Pulled the tertiary winding from the center of the coil, and then proceeded to remove 10 turns from the tuned secondary winding. Reassembled and reinstalled in the radio, tack soldering the wires to it as I assumed it would have to come out again.

Results: 1200 kc now comes in at 120 on the dial - but the oscillator (high frequency) screw is still all the way out on the tuning condenser to achieve this. My SSTRAN, at 660 kc, comes in at 70 on the dial, and that is with the low frequency padder wide open as well.

So it appears some more turns need to come off.

I think tomorrow or Sunday, when I work on it again, I'll try just five more turns. I don't want to go too far, now that I'm getting close...

I also oiled the tuning condenser bushings/ball bearings, which helped the cutting out a great deal; it is nearly eliminated now. Perhaps after the oil has a chance to soak in, it will be even better.

[Ron Ramirez]

More progress, if anyone's still reading:

I pulled the oscillator coil back out again. This time, I removed five more turns as planned. Reinstalled.

The 1200 kc signal from the signal generator was now coming in around 1140. This was a good thing, as I was able to (finally) turn the high frequency oscillator trimmer in somewhat to bring the signal back up to 120 on the dial.

Meanwhile, down the band...660 now comes in around 684 on the dial.

I think this is the best that I am going to achieve with this one, and have declared victory. The 91 is very sensitive, even with a temporary 20 foot antenna strung along the ceiling of the basement. (I have yet to put up an outdoor longwire at this location; this will be a spring project.)

Things that remain to be done: New rubber bushings under the tuning condenser, giving the chassis a good cleaning, and installing an 8 inch speaker in place of the stock 10-1/2 inch speaker (this chassis came from a console, but will be going into a cathedral cabinet).

[klondike98]

Still reading congrats on solving that oscillator coil problem.

[Ron Ramirez]

Thank you, Bob!

[w4rtc]

Hi Ron
Somehow I missed this post until today. It is interesting about "modifying" the Osc. Coil. Good work. Joe

[Ron Ramirez]

Thanks, Joe

Back to doing some more projects around the house...while I wait for the six feet of snow (actually, the prediction is for 4 to 6 inches) to begin...

[vinzer]

We already have more than 6" more like 8" and still falling.

[morzh]

The maximum I have ever seen is about 4 or so feet high when I lived in central Russia, in 80s. This was not overnight, but temps being very low the snow accumulated. So when we pushed the car through a narrow plowed corridor the snow was at the level with the car's roof.

[TA Forbes]

Hopefully you get no snow.

Been reading too, as I have both a 91 and a 14 (late) on the "to do" list.

[Ron Ramirez]

We only received around an inch of snow, but it's as cold as...well, you know. We went from 40 degrees around midday yesterday to below zero this morning, where it has basically remained since. Tomorrow it is supposed to reach the heights of 14 above. Brrr!

I'll look for a speaker for the newly repaired 91 chassis next. I have one...actually I have several...but I will probably have to swap field coils with the 10-1/2 inch speaker I have, as the 91 wants a speaker with a 3200 ohm field, and most of my K series speakers have 1100 ohm fields.

[37silverstreak]

Glad to hear you got your 91 playing well Ron, congrats . Mine is working well also, but still trying to get the shadow meter to work right.
Woke up this morning to -14 below with 25 to 35 mph winds! Wind chills of around -45 below zero ! Had to take a personal day as my car refused to start, heck it would barely turn over!! Took over half an hour to pull the battery, as my car sits outside and I had to work in the wind. Fumble around 10 minutes then into the house to warm up and go out again! Finally got the battery in the house and on the charger. Hopefully a warm, fully charged battery will get her started tomorrow!
Kevin

[morzh]

Ron

You could use a resistor (with proper power rating, which you probably know) in series as the field coil in 91 is not used as a filter.

What I do not understand there, if they use 2 speakers (I guess 2nd is an option) they plug the second field coil between the B+ and Chassis which (if the fields are similar) would create a nice divider and lower B+ quite a bit. Or is the second one some sort of a twitter and has a field of very high resistance?

[LASJayhawk]

They seemed to like using a 1.1K and a 3.3K field on the dual speaker set ups.

There is a nice spreadsheet of Philco speakers in Riders volume 4 in the Philco section starting on page 4-44

[Ron Ramirez]

There is a nice spreadsheet of Philco speakers in Riders volume 4

Also here, in Microsoft Excel format and covering 1929 to 1938 models:

http://www.philcoradio.com/phorum/showth...hp?tid=215