[Joeztech]

Today I finished rewiring the chassis including most of the capacitors and a large number of the resistors. I am going to have to order a few more capacitors to finish up. I under-counted the .01mFd capacitors. I checked the B+ circuits with the field core speaker connected and found no shorts to chassis. I added a polarized AC power cord and turned the set on. All lamps lit and the tube filaments came on then I heard some slight hum and crackling from the speaker. The hum is not audible at any reasonable distance from the speaker. The volume control cause a considerable amount of static as it is adjusted as does the tone control. There is some audio oscillation as the volume is brought up.

I hear some clicks as I tune across the AM band at consistent spots. I believe the front end is working, but the IF is out of alignment due to having the IF transformers out and changing wires. The 1st. IF transformer slugs had to be turned nearly all the way in to get the assembly in and out of the IF can shield. I have my RF signal generator warming up and passing the signal by the frequency counter to be sure of the output frequency. The RF signal generator has a switchable internal audio signal generator. I will begin by injecting an IF signal and peaking the IF transformer coils until I can get a signal all the way through to the detector circuit.

I plan to do several things before I do more work on the set. First I have to put together some sort of wooden base to hold the chassis upright and secure it for access to both sides for troubleshooting and alignment. The radio chassis is heaviest on the end where the power transformer is located and at the front where the controls and push-buttons are located. It is heavy enough that I don't want to run the risk of having it turn over while I am working on it. It is sort of a basket case with the antenna, speaker and mounting board attached and trying to do much of anything without the risk of something falling over. I don't want to break any tubes.

Many thanks to everyone for their help along the way so far!

Joe

[jerryhawthorne]

Great progress Joe! Sounds like your almost there. Always a problem on larger chassis trying to get them positioned to be able to work on both sides. I always wish I would have built some type of holder to allow rotation but never have.
Jerry

[Joeztech]

Jerry;

Thanks for the comments! Here are a couple of pictures of my solution for this particular chassis. I realized that it would be impossible to do any sort of decent alignment with it in any other position than standing on edge. I do not have the adapter sockets that Philco describes in their alignment procedure, so I will be finding a way to couple signal in from the bottom side of the chassis. This platform was made this afternoon using some left over 3/4 inch plywood, some large right angle steel brackets and some wood screws. I used the chassis bolts to hold the chassis to one steel bracket on the front side and to the vertical piece of 1 X 4 on the back side. It is nice and stable enough to make the rest of the job far easier. One thing that would make the job even easier would be to have a 4 or 5 inch field core speaker with the right field coil resistance. The 12 inch unit is cumbersome on the bench.

Joe
   
   

[jerryhawthorne]

Now that is nice and creative. Much better than I do and looks very stable.
That chassis is absolutely gorgeous!
Jerry

[Joeztech]

Thanks again Jerry;

I put a couple of pieces of Masonite under the end where the 42 output tubes are to provide more air circulation. I just wish now that I had done this before I started! Oh well, better late than never. I am going to order some more replacements for the remaining paper capacitors. I mis-counted originally and did not order quite enough. One thing I discovered as I was finishing the cap replacements was that the resistors in the phase splitter circuitry and split phase drivers had changed in value anywhere from 19% to as much as 57%. I am glad I ordered plenty of them to have on hand. I hate having to disconnect things twice in order to replace something I could have taken care of in one step.

Joe

[codefox1]

Yep, for the couple of bucks or so, I and many but not all retorers replace all the carbon resistors at the same time as all the paper and electrolytic capacitors. No foolproof wayto test any of these components anyway for today and for a month from now. Tubes may outlive all of us, which makes no sense, but might.

[jontz]

Joe,

Did you paint that chassis or just really clean the heck out of it? It looks amazing!

[Paul Philco322]

Check out this thing, price is sky high but these things were made fro the radioman I believe.
http://radiotiques.com/picture.asp?Path=...493b%2Ejpg

Paul

[Joeztech]

Jontz;

Yes I painted the chassis. It began with a mouse nest infested chassis, many wires chewed into etc. See this thread in the same Phorum: http://www.philcoradio.com/phorum/showth...p?tid=7984 (Preparing 40-201 for painting chassis)
It shows pictures of the before appearance of the unit. It took removal of all the top of chassis parts, scrubbing with gojo that had pumice in it and a wire brush, some Naval jelly, some sanding followed by masking and gray primer, then the brushed satin nickle Krylon paint that Ron recommends. It was a time consuming effort. My son-in-law was amazed when he saw the results recently.

Joe

[Joeztech]

Thanks to rubber parts from vendors mentioned elsewhere on this site, I managed to find and replace most of the old crumbling rubber parts. One exception is the grommets that hold the tuning capacitor. Fortunately the ones on this radio are still in fairly good shape although one has a crack and I would like to replace them all. I still need the ones that mount the push-button assembly to the tuning control panel up front. They are available, I just need to order them.
I found some black rubber grommets at Lowe's that fit the speaker mounting screws and speaker, so those are taken care of.

I think most of us can manage to create custom holding arrangements for our radios without having to spend megabucks. The main thing is to be able to work carefully and safely. I would hate to have this radio fall on my legs or feet from my desk. It is quite heavy. Most all of my electronic equipment seems to be heavy as over 60% of it is tube type still. I do have one item that is solid state and it is also quite heavy due to the large power transformer in it.

Now to order those extra capacitors and start troubleshooting and aligning!

Joe

[hsusmann]

Wow, nice chassis job!

I'm going to have to start stripping off mine on future
jobs and see if I can get them looking this good.

In the past I have not worried too much about
how the chassis looks but after seeing this I may
start doing more.

Herb S.
Ithaca NY

[Joeztech]

hsusmann;

It is a considerable task to undertake. I would say only do it if you have some experience with IF transformers and the possibility of having to put new wires on them. Each radio will likely be different. Some are easier than others. I just discovered this morning that in this radio after I started the alignment, I was able to peak the IF signal in the first IF transformer and also in the 2nd. IF transformer plate circuit, but there is something not right in the secondary at the detector tube, so I am going to have to remove this one once again and check the parts inside. Right now I am thinking that either the cap across the secondary winding is bad (open) or one of the 100pFd caps at the low end of the secondary is bad (again maybe open). At least I know that the circuits from the mixer through to the 2nd IF transformer primary are working. If you are not afraid of dealing with the fine wires on the internal coils, then go ahead and give it a try.

Take good quality photos of the underside of the chassis before you begin and you may also want to make hand sketches of where every wire goes. I had real problems determining the color of the wires on this radio due to fading and the factory used some alternate colors other than what was shown on the schematic. There are always some confusion factors. I used cotton balls to cover the openings in the chassis above the trimmer capacitors in the front end. I could not get masking tape there using the best tools I had available. The only way would have been to drill out rivets, remove the trimmers and associated wiring. That would have been a far greater task than I wanted to consider. It is so easy to damage something in the front end circuitry.

There are lots of challenges in these old radios. Once it is up and running again it gives a great sense of satisfaction and accomplishment.

Joe

[hsusmann]

Joeztech:

OK, thanks for the advice. I am very familiar with old radios, IF transformers, etc... and have re-wound several in the past. I have a background in electronics going back to when I was 10 years old taking apart old TVs etc... I'm a long time ham radio operator and have
built lots of ham equipment over the years.

I have a Masters Degree in Electrical Engineering also (not that that taught me anything at all about vintage electronics!) so can pretty much re-design something if need be.

In the past I have focused on just getting the set running again and not worrying too much about the historical asthetics. I am now starting
to worry about this also as I finally get enough time to put into this kind of work!

Thanks!

Herb S.

[Joeztech]

Herb;

OK, I understand. I just did not know your skill level. You sound much like me. That is how I got started too. I was a teenager in high school before we had television. Dad retired and I began to learn how to repair it. I am also an amateur radio operator, although I have been inactive for a while. I need to get my tower and antenna up. I have a start on it with the first section and base embedded in concrete about 50 ft. from our house.

I just figured out my problem with the IF and detector in this set. I was feeding a modulated 455kHz signal in at the antenna input as Philco suggested and was not getting much output. I finally discovered that when I wired the first IF transformer to the IF tube socket I got the secondary and tertiary windings swapped. The tertiary winding is supposed to go to the suppressor grid and the secondary of course is supposed to go to the signal grid of the IF amp tube. After I corrected that I now have a good tone at the audio output and a strong signal to the detector circuits. I sometimes do that and make stupid mistakes. I had made a drawing and at one point I had it connected right and because I had changed the wire colors I managed to get it wrong. Now it is correct and I have a good chance of getting this set working. I discovered my mistake by making ohm meter checks. The secondary winding is supposed to be about 8-10 ohms and the tertiary winding is less than 0.1 ohms. Boy did that make a difference!

I wish you and your family a Very Merry Christmas and a Happy, Healthy and Prosperous New Year!

Joe

[hsusmann]

Joeztech:

OK, I'm glad you got it sorted out
I have been down that road also, stupid mistakes
are sometimes the hardest to find.

I don't go back as far as you do I think. TV was fully
established when I was born (1960). My grandfather
had a TV/Radio repair shop in Kenmore NY (Buffalo
area) and I have fond memories when I was about 7 or 8
and later watching him fix TVs etc... He was a ham going
way back to the spark days. I have some of his
newer ham gear now. He dropped out of high school to
go to radio school and beyond that was largely self-taught
and very good at his trade.

Anyway, I've been working on a 1935 GE Radio (A-65) the
last few days and finally got it all re-capped and re-resistored.
Works like a charm now! Need to do an alignment next
and also set the dial spread and offset.

Hope you have a great Christmas also!

Herb S. KA2ZOH
Ithaca NY