[KCMike]

Ron this has to be one of the most challenging restorations I've seen you do. So many different problems to over come. Been following all along and it looks like your in the home stretch.
 This will be a great thread for future restorers to turn to for help.

[Ron Ramirez]

Thanks Mike, I appreciate that.

[Arran]

Ron;
  I looked up the infamous Mr. David Grimes last night because of this thread, and because I remember that he used to run a radio manufacturing firm back in the early to mid 1920s. One of his more famous contributions was a series of sets using his "inverse duplex" circuit, without studying it further it was a sort of hybrid between a TRF and a regenerative circuit with his own spin, where they would use three or four tubes to do the job of five. It sounds interesting but for a 1920s radio they were rather complex, even compared to an early superhet, the man clearly did not adhere to the KISS principle, which was likely why his company failed around 1927-28, why pay more for a finicky set when you could buy an A.K model 20, or a Freshman Masterpiece, for much less that's easy to operate? Here I thought that a Sparton Equasonne (Lester Jones Technidyne) circuit was convoluted, but those have nothing on some of Grimes stuff. After what I read here I think I will stop collecting big Philcos at the model 116 or 3116, unless I happen by a 37 or 38-116 cheap, or luck into a model 380 somehow.
 An interesting twist to the David Grimes story is that the Canadian branch of his company was partnered with, and later owned, by the Pollock-Welker/Phonola phonograph company, called the "Grimes Radio Corporation of Canada, LTD". They did not continue with the Grimes inverse duplex designs after the U.S company went bust, or selling sets under the David Grimes name, they went into the AC radio market, and at first built some Well Gardner sets under license, then made some sort of arrangement with U.S Radio and Television manufacturing (or assembling) chassis under license for a time. They carried on manufacturing under the Grimes Radio Corp. name until about 1936, primarily making private label sets for Eatons, Simpsons, etc., as well as under the Phonola brand, then changed their name to "Dominion Electrohome Industries", however they never sold any sets under the Electrohome name until after the war.
Regards
Arran

[Brad Winder]

Ron,

I'm following this thread with great interest. Very thorough restoration! I own a 37 and 38-690; the 38-690 was previously electrically restored, and works well- thank goodness. The 37-690...I started restoring it 17 years ago, and I first went through the power supply/amp chassis, and re-stuffed all the original tubular and bakelite block caps. I started on the main chassis, intending to do the same...but life got in the way, and it's been sitting on the shelf for about 13 years now.

In regards to David Grimes and Electrohome, I collect Canadian Grimes/Electrohome sets, and the early ones are very interesting in their chassis design. Restoring them to good working order...that's another matter. Very complex as Arran said. And Grimes/ Electrohome was still using the David Grimes design on their least expensive radios into the 1932 model year. 

[Ron Ramirez]

Thanks Brad.

May 30.

Time to reassemble the RF unit.

After working for 2-1/2 hours, it was mostly together again:

[Image: http://www.philcoradio.com/images/phorum...90_081.jpg]

[Image: http://www.philcoradio.com/images/phorum...90_082.jpg]

[Image: http://www.philcoradio.com/images/phorum...90_083.jpg]

[Image: http://www.philcoradio.com/images/phorum...90_084.jpg]

I still need to replace the two grid cap leads which you can see in the third and fourth photos, attach a grid cap connector to one green wire which is already in place, reattach the sides, install the band switch shaft, and put the whole thing into the 38-690 tuner chassis.

Getting closer...

[tbone]

Great job Ron

I’d say you made quick work of the sub chassis, well a fast as you can on a unit of this complexity. All connecting wires replaced as well. This requires a break for a good adult beverage!

I made a hand drawn map of the wiring and what terminal strips/locations they went to, including lead dress.

Enjoying the post thoroughly. Thanks for taking the time.

[Ron Ramirez]

Thanks Tony.

I did not replace every resistor in the oscillator section of this RF unit, nor did I replace any of the mica caps in this RF unit.

I also purposely cut the connecting wires too long, as I may just try it out without physically attaching it to the tuner chassis. If it works...great...and I'll install it the right way. If it doesn't...it will be a bit easier to troubleshoot. I haven't made a firm decision yet on that (whether to fully install this RF unit in the tuner chassis or not for testing), however.

[Ron Ramirez]

May 31.

I came home from work this evening to find a large tree branch hanging from the tree it had fallen from, thanks to a storm that passed through today. The broken end was stuck in a fork between two surviving branches.

I managed to get it down (it wasn't easy), cut it into four parts, and set it aside to take to our local yard waste dump on Saturday. (This is where having a pickup comes in handy...beside hauling radios )

Nevertheless I still had enough time this evening to put the finishing touches on the 38-690 (formerly 38-116) RF unit:

[Image: http://www.philcoradio.com/images/phorum...90_085.jpg]

[Image: http://www.philcoradio.com/images/phorum...90_086.jpg]

[Image: http://www.philcoradio.com/images/phorum...90_087.jpg]

It will be connected to the 38-690 tuner chassis tomorrow evening, most likely, barring any more downed tree limbs - it's past my bedtime as I type this and I can hear thunder again

[Ron Ramirez]

June 1.

Silly me...I thought I would have time to install the RF unit into the tuner, set everything on the bench, and try it out tonight.

Not so - the RF unit took longer to finish up and install than I thought it would.

First off, I discovered that I had forgotten to attach two wires to the RF tube socket in the RF unit; this was soon taken care of.

After two hours or so of work, the RF unit was in the tuner. I went ahead and mounted it in proper rather than trying to connect it loosely.

[Image: http://www.philcoradio.com/images/phorum...90_088.jpg]

[Image: http://www.philcoradio.com/images/phorum...90_089.jpg]

[Image: http://www.philcoradio.com/images/phorum...90_090.jpg]

I not only went by the other RF unit and my notes to make sure each of the 16 wires was properly connected from the RF unit to the tuner, I also double-checked by comparing the wiring to the schematic. All is correct.

So...tomorrow, I will find out if this RF unit is going to work correctly. With all coils having good continuity, theoretically, it should. But the other RF unit had good continuity on all coils also. We shall see.

[Arran]

Hopefully that was the problem, otherwise I would start looking elsewhere such as in the IF or second detector sections, is it possible that something was detuned or miswired?
Regards
Arran

[Ron Ramirez]

Arran

Post #22, page 2, this thread:

May 20.

So...I set the whole thing up (both chassis, woofer, and both tweeters) on the workbench and tried it out.

With the 690 set to band 1 (AM), I fed a 470 kc IF signal into the grid cap of the mixer tube.

Guess what...the signal came through loud and clear.

The tuner itself can pass an IF signal just fine; therefore narrowing the problem to the other RF unit. I've even aligned the IF strip already, also on May 20.

If it doesn't work this time around, I will be checking voltages at multiple locations to see if I can pinpoint the trouble. But I'm optimistic that this RF unit will work. One thing for certain...I will find out later today.

[Ron Ramirez]

June 2.

At the workbench.

It's Alive!



I will post a photo and a video later.

I double-checked the audio interstage transformer to make sure all was well...it was.

Then I hooked everything up...and it is working on all five bands!!!

Now it is time to do an alignment and then get this thing off my bench. I have an RCA T7-5 patiently waiting its turn, among many others.

[Nathan Slingerland]

[Ron Ramirez]

I took this photo right before I turned it on:

[Image: http://www.philcoradio.com/images/phorum...90_091.jpg]

Said a silent prayer, turned the bass control to ON, and...

Lots of static. At first I thought there was a short under the chassis, so I quickly turned it off, pulled the tuner chassis up so I could look underneath, and turned it on again. Seeing no sparks or smoke, I let it warm up and it began to play! Apparently I need to clean that band switch some more. But the static went away as the radio continued to play, which is why I think there was some dust/dirt up in the band switch somewhere that I missed. I will go over it again with some conventional contact cleaner (the kind that evaporates). I had initally cleaned the contacts with DeoxIT five days ago when I had the individual sections apart.

As you can see, I have not yet installed the automatic tuning assembly - I just wanted to see if the radio would work or not before proceeding.

Here is a video demonstrating reception on the AM band - you won't hear many stations as there aren't very many near where I live:

[Video: https://youtu.be/msVZWrxI9y0]

I tried all five bands and, while I did not pick up much, it was obvious that all five bands were working as I could tune across various weak carriers and noise. Best of all...unlike the last RF unit, there is NO cutting out or static while changing bands.

A thorough alignment will make this radio receive at its full potential.

Man, it's great to finally be in the home stretch! It's only taken three months...

[mikethedruid]

Congratulations, Ron ! That was a herculean task. It is always a pain in the rump when you have to undo mischief created by some previous "restorer." I am dealing with that now on a 37-630, code 126, but your receiver is far more complex, and so was a whole lot more of a challenge. My compliments and respect for a huge task so well done.