The PHILCO Phorum
38-2 tuning mech - Printable Version

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38-2 tuning mech - doug-5er - 10-18-2014

Hi all,
This is the first post for me on this forum. Icon_wave I have a problem with the tuning mech i can only move it about 
a 1/4 turn in either direction, it seems like it is jammed.You'll have to bare with me as this is the first time i have
had the chassis out of the cabinet.Should the band switch move when you turn the dial ?Doesn't sound right to me,
i can turn it by hand using the crank or tuning selector but as i move the band switch moves also.The inner part of
the 2 piece tuning knob was broken when i got it, this tells me it been that way for awhile.Is there something engaging 
that should not be?Your thoughts? Thank you in advance.

Doug

RE: 38-2 tuning mech - sam - 10-18-2014

doug
welcome to the phorum
sam

RE: 38-2 tuning mech - morzh - 10-18-2014

I suspect the dial might be similar to the others of this kind, like on my 37-116.
If yes then no, 1/4 turn is not normal.
The outer piece should rotate about 3 turns to move the dial full scale.
And the inner piece itself multiplies that a few times.


No, the band switch is totally separate from the dial turning mechanism and is not engaged when the dial is being moved.

In a nutshel, even if it all worked, the mechanism requires some cleaning and lube.
You could have coupling rubbing against something that would make band switch move.....you will have to disassemble it.

Note: make photos or sketches of the assembly and parts, and the way they mount, this thing is quite not uncomplicated Icon_smile

RE: 38-2 tuning mech - doug-5er - 10-18-2014

Thanks Morzh,
The dial is exactly the same as a 116 I have that console also.This was my thinking,I can take the round area that holds the station tabs and only rotate it a small amount before the band switch starts to engage,as soon is the switch gets to its final position either left or right the mech stops. I removed the plate on the face of the area of the station tabs there
are a ton of adjustment screws these must be station settings,any surprises when i remove this plate.Also one more ?
if I may, the box on the underside of the chassis that houses more components resistors and such there are 4 nuts
2 on either side of the tuning cap do those undo that box.The band switch rod is in there to.

Thanks 

RE: 38-2 tuning mech - morzh - 10-18-2014

If you did not disassemble 116, then you do not have experience with it.
But...before you go too deep, you have no bad surprises.
The adjustment screws stay put unless you remove them.

the only thing you need to remove is the handle.
I would also remove the center cap with three small screws as it is thin metal and might bend when bouncing against the bezel, and also damage the bezel. Same when putting it back.

The coupling is way outside and does not require the mechanism disassembly, so you will see it once the chassis is out. Then you can start observing what is happening when you rotate the dial.

RE: 38-2 tuning mech - doug-5er - 10-18-2014

Sorry morzh, I failed to mention that the chassis is out of the cabinet.So I can see what is going on as i move the
the dial. I would say i need to get into the dial area mech further.Don't mean to push but how do I remove the
cover box under the middle of the chassis? I need to get inside there anyway to check and replace parts as needed.
My 116 is a beautiful set and is in perfect shape an haven't touched it.

Thanks for the help. 

RE: 38-2 tuning mech - morzh - 10-18-2014

I do not remember all, I went part by part, drawing sketches as I progressed.
What is strange is that the mechanism is not supposed to engage the switch.

You could try to look under the dial and see if anything rubs.
The mechanism is complex and unless necessary, I would try to abstain from ful disassembly.
if you go ahead, start with the knobs, then three small screws will remove the cover, then the teledial hande and so on.

RE: 38-2 tuning mech - doug-5er - 10-18-2014

morzh;Thank you for all your help. I will let you know how it turns out.

RE: 38-2 tuning mech - Ron Ramirez - 10-19-2014

Go to the link below and download Service Bulletin 273, which gives complete details on Philco's Automatic Tuning mechanism including views showing all of the parts and disassembly instructions:

http://www.philcoradio.com/phorum/showthread.php?tid=5938

RE: 38-2 tuning mech - doug-5er - 10-20-2014

Thanks Ron for the file,I think by the time I get through this I will be an expert Icon_e_wink What it looks like to me is,the
The part that holds the dial scale and the part that holds the band indicator are within very close tolerance of
each other,I'm talking paper thin or less.If for some reason the 2 are in contact with each other ie; grit or ?
The 2 parts would bind as they pass that close.Because the 2 are pot metal corrosion could be a factor also,
although I don't think so. 

Doug   

RE: 38-2 tuning mech - morzh - 10-20-2014

I did not have tolerance problems there.....the band switch shaft has some contaption to move the band indicator but I do not remember them rubbing or close.
In case the has been too little space light grease like lithium might help to alleviate rubbing.

RE: 38-2 tuning mech - doug-5er - 10-20-2014

Hi morzh,
I don't think you are seeing exactly what area I'm talking about.If you look at the link Ron sent,Go to picture Fig #2.
Look at where arrow #13 is pointing,the outer part is the dial scale the inner is the part the band housing they pass
each other with a very close tolerance like paper thin,they revolve around each other.This is where they are binding
if grit was to get in there the tolerance is so close they could bind.I sprayed some WD-40 in there we shall see.If that
is it I will use some lite grease between the two.  

RE: 38-2 tuning mech - morzh - 10-20-2014

yes that is the part I referred to, it looks like two arches connected together and then it goes to the lever connected to the shaft. The upper arch moves the wheel with slits to highlight the bands.
(I have this doc but was not able to really use it....I have poor spatial imagination Icon_smile ) I eventually used my own sketches I drew while disassembling.)

I wonder why it catches; mine didn't.

Anyways, be careful with that insulating tape wrapped around the bushing - it is a part of the audio switch, and should the insulation be broken, the switch will no longer work (that is it will silence the radio permanently).

Also there is that copper retaining leaf spring piece that goes in the groove there, also carefully sketch how it was before.

Then there is that spacing ring 13. This in fact might be your problem. Record which way it goes (it is not fully the same on either end but can go either way and I am not sure it should). It all pot metal I think, I wonder if this ring expanded or warped.

RE: 38-2 tuning mech - doug-5er - 10-20-2014

Well the WD-40 freed it up,but there is still some contact inside the mech somewhere and i can't tell where it is.
I can hold the band switch and turn the dial freely, B4 it would only turn a small amount.Now i have full range
on the tuning cap,so i guess this is a good thing.I'm still a little leery about taking the mech apart,don't wanna
open a can of worms. 

RE: 38-2 tuning mech - morzh - 10-20-2014

There is no can of worms, just have to be diligent with your sketches.