[Ron Ramirez]

Thanks Ed. A lot of work, yes indeed!

Tonight I did a bit of troubleshooting.

First, I tried injecting a signal in the SW range. Result: Nothing.

It appeared that the oscillator was not running on bands B, C, or D.

So I did not remove the Magic Brain, but I did remove the top and bottom shields so I could merely flip the entire chassis over and have access to the bottom of the Magic Brain unit. I wanted to specifically examine the area around the oscillator tube and its associated coils, capacitors, and wiring.

Take a good look at the photo below. There will be a test later.

   

Now carefully examine the partial under-chassis wiring diagram of the oscillator portion of the Magic Brain. Again, take a good look, keeping in mind that this diagram is upside down in relation to the photo above.

   

Do you see the mistake I made?

Give up? Well...I accidentally switched the red and green wires at the band switch.

 

After unsoldering, switching and resoldering, it looked like this:

   

Now it matches the RCA diagram.

Did the wire swap fix the "No SW" issue?

You be the judge...

[Video: https://youtu.be/Me9Yj2YS_70]



You will notice in this video that I'm still having difficulty switching from band B to band C.

I think that tomorrow morning, I will remove the Magic Brain top and bottom shields again, hit the band switch contacts with DeoxIT as carefully as I can, and then leave it alone until tomorrow evening or Christmas Day, at which time I will attempt an alignment.

[Ron Ramirez]

Also tonight:

I had previously noted that someone had worked on the original 9T chassis, but the work was not to my liking.

   

   

Just for fun, I decided to try out the 9T chassis just to see if it would work.

Keeping one hand on the switch of the power strip which the 9T chassis was plugged into - in case an Edgar Montrose type "KA-BOOM" occurred - I powered up the 9T.

Much to my surprise, it works...on all five bands...

[Nathan Slingerland]

Great job tracking that down Ron!

[Steve Davis]

Great job, Ron! It's always a good feeling when you find the problem and make the radio work as it should. 

Steve

[Ron Ramirez]

Thanks, Nathan and Steve!

I did go back in this morning and spray the band switch contacts with DeoxIT. I'm not going to attempt alignment until tomorrow.

Earlier this evening, I found this thread on a 10T restoration at ARF:

https://antiqueradios.com/forums/viewtop...07b9c9e33f

I wish I had read this before I started on my 10K chassis. I've learned some things from this, chiefly the proper way of removing the Magic Brain from the main chassis and what needs to be removed prior to removing the "Brain". The link above also gives some brief details on alignment - I now know that those trimmers which are locked in place with a wrench must be pushed down and/or pulled up instead of turned like a screw as with conventional trimmers.

Oy...alignment should be fun...not.

[Ron Ramirez]

So this afternoon I aligned the 10K chassis. Those compression/plunger trimmers are quite the adventure to adjust. Well, actually, they weren't all that hard to do.

After completing the alignment, I reinstalled the mounting brackets under the chassis and reinstalled the Magic Brain cover on top of the chassis. Then I put the 9T speaker back into the cabinet, after which I installed the 10K chassis into the 9T cabinet.

By now it was around 4:55pm EST. I tried it out with my longwire. Distant stations were already coming in as it was getting sort of close to sunset here by then.

With the speaker (and radio chassis) on the workbench, it seemed to me that I was hearing some distortion from the speaker on loud passages. But in the cabinet, the speaker sounds fine. The fidelity-selectivity control of the 10K chassis really helps make this setup sound really nice. The 9T chassis does not have a fidelity-selectivity control.

Paul Philco322, if you're reading this, you will be interested in knowing that I picked up WBZ (Boston) on this set just before 5pm EST!

Photos (and maybe a video) later.

[Paul Philco322]

WBZ is known to cover 38 states and is heard well in Ohio so Indiana is not to big a stretch. You can catch the local news. Even though BZ is now an I Heart station it is run pretty well and has a very strong local focus and staff. Good test for that RCA.  Paul.

[462ron]

On Tuesday, while waiting around in my car and fiddling with the radio, I actually pulled in WBZ at 2 PM, way before sunset in eastern PA! I've never had that happen before. Crazy atmosphere I guess.

Ron

[EdHolland]

The 110K2 I restored a year or so ago had one of the plunger trimmers. It confused me for a while, as I tried to turn each direction to get an adjustment . This wasn't helped by the fact that some of the other caps used to pad the tuning on that band were out of tolerance, so I could not get the adjustment called out in the alignment instructions. Eventually I unearthed the culprit, replaced it with a new silver mica cap and all was well.