[Mondial]

That's great! You are certainly making progress.

Have you tested any of the tubes? Weak tubes will make a big difference in the sensitivity. Most of my original tubes in the 47-1227 were very weak.

[criageek]

Thanks Mondial - No, I haven't tested any of the tubes.  I had a tube tester but got rid of it years ago.  I just ordered a 7F8, a 6BA6, and a 7R7.  I'd have ordered a 7X7 as well, but Tube World was out of them.  I'll tweak up the alignment as best I can, and then try the new tubes when they get here.  If I decide I'm probably going to do radio restoration for awhile I'll look to pick up another tester.

Rich

[jcassity]

here is what play things of the past has for 7 __7 tubes
i am not sure how the letter in between affects compatibility
He shows no 7AF7's for me but has them so maybe he has the 7x7 you need.

7A7 2.00 3.55
7A8 0.00 3.80
7AG7 2.00 4.25
7B4 2.00 3.00
7B5 2.00 3.00
7B6 2.00 4.00
7B7 INQ. INQ.
7B8 2.00 3.00
7C5 2.75 7.25
7C6 INQ. INQ.
7C7 2.00 3.75
7E6 2.00 2.90
7E7 0.00 2.75
7F7 2.50 7.05
7F8 2.75 7.50
7G7/1232 INQ. INQ.
7G8/1206 INQ. 5.85
7H7 2.00 4.00
7J7 2.00 3.50
7K7 2.50 6.25
7L7 2.00 3.00
7N7 3.10 7.25
7Q7 2.00 3.00
7R7 0.00 3.65
7V7/1231 0.00 3.75
7Y4 2.00 3.00
7Z4 0.00 3.00

[klondike98]

You can see the specs and pin outs for tubes at http://www.nj7p.info/  then click on "Tube SQL Database" and enter the tube number and click "Lookup".

Another great tube supplier is Bob Dobush at Find A Tube: http://www.findatube.com/

[criageek]

Thanks for the tube info guys.  Before I buy any more tubes I'm looking to pick up a tube tester.  Just called a guy that has a couple listed on Craig's List.  Hopefully he calls me back soon with some good news  ;)

I need recommendations for doing the FM alignment.  It's been many years since I did any of this so I'm basically re-learning.  I believe I can do the IF section with the B&K E-200D.  I just need to inject the modulated (AM) 9.1MHz into the grid of the 6BA6 1st IF amp, right?  But then to tune the front end I assume I need a signal generator that will produce an FM signal.  If that's the case, what should I look for?  I've found nothing new that is reasonably priced so I've looked at older units.  I've seen recommendations for the Sencore SG-165 and I've been looking at a couple of HP 8640B's on eBay.  Having worked in a test equipment cal & repair lab I know the HP is a really nice unit.  If I'm going to stay in this hobby long term I'd have no problem plopping down $200 - $300 for one if it's something I really need.

What's the prevailing opinion?

Thanks,
Rich

[Mondial]

You don't need a fancy signal generator to do the alignment. The Philco procedure assumes you only have an AM generator. Worst comes to worst you can align the front end on received broadcast signals. This is sometimes preferable on the FM band as you will be aligning the RF stage to the internal FM dipole antenna.

That said, its nice to have a quality generator. The 8640B is fine , but they are getting a bit aged now and have problems with the plastic gears in the switching mechanism. I have one, but every time I go to use it, there seems to be a new problem that's developed.

A good generator I can recommend is the HP 8601a. It is a sweep generator with both AM and FM mod. They are small and fairly inexpensive. There is a hybrid circuit in the output stage that goes bad, but someone on Ebay is selling a retrofit replacement module.

[criageek]

Thanks Mondial - I'll check it out

Rich

[criageek]

Today I went through the entire AM and SW alignment and I think they are pretty close to spot on.  I also set the pushbuttons.  I don't get anything on shortwave.  It looks like it requires a different antenna that would connect on the two pins of the FM antenna connector that are empty on mine.  Does that sound right?  On my connector in the cabinet there are two wires on pins 3 and 4 that are stapled around the perimeter of the cabinet, but pins 1 & 2 are empty. 
   

The FM alignment is another story.  The procedure says to adjust the input for a 10 volt reading across C12 in this schematic (it's connected to pin 6 of the 7X7)
   
I only get 200mV - 300mV, negative, with the input adjusted for a fairly loud signal from the speaker.  I looked at it with the scope and it's DC.  Does this mean anything to the experts?

Thanks,
Rich

[criageek]

Today I went through the AM and SW alignment again just to be sure I have it right.  AM was pretty close but shortwave was a bit off.  But I still get no shortwave.  I tried running a wire out the window and into the back yard but still nothing.  Still nothing on FM either.

On the positive side, yesterday I received the 3 tubes I ordered (7F8, 6BA6, 7R7) so I decided to pop them in and see if there was any difference.  I get more volume (although it's still not where I think it should be) and I can detect a couple more faint signals where there was none before.  I bought a tube tester off Craig's List and will go pick it up next week and test the rest of the tubes.  Will tube replacement affect alignment?

Here's something pretty cool.  I'm missing one of these spacer/eyelets for mounting the pushbutton assembly:
   
My new 3D printer is supposed to be here sometime in the next couple of weeks so I drew up a 3D model for one and will try printing one:
   
I also broke the stiff cardboard/fiber shield under the pushbuttons when I took it off.  I assume this is some sort of light shield?  Anyway, I drew up a 3D model for that as well, so we'll see how that turns out.

Rich

[jcassity]

rich

on my radio, i had a single wire out in the air and was able to get broadcast but no short wave.
it occured to me my big square antenna inside the cabinet had two wires.

i added another random wire off shortwave and i got shortwave !

now get this...
i have two random wires,, one from screw 1, one from screw 2.

i remove the wire that was for short wave keeping the other wire inplace and shortwave signals kept coming in.

so........... i dont know what i did to fix this but the problem is gone

[criageek]

Thanks for the info jcassity.  I fiddled with a long 2 conductor wire connected to terminals 1 and 2 and ran it out the basement window into the yard.  It was about 25 - 30 feet.  Nothing.  Tried twisting the ends together.  Still nothing.  Haven't spent much time on it since I picked up my Fairbanks-Morse but I think it's time to set that aside and get back to the Philco.  I'm picking up a tube tester tomorrow so we'll see what that says.  The 6AG5 is an RF amp for the FM section so maybe I'll get lucky and find that it's bad and can at least get the FM working.

Rich

[Mondial]

If you want to try the wire for SW, only connect it to terminal 1. Terminal 2 is ground, so if you have a long two conductor wire connect both conductors to terminal 1 and see if you get any reception.

[Warren]

... I have never really received a sw station on on my 47 1230 either....you can hear the usual static between stations but not a station to come in. My fm does work though.

[criageek]

Thanks Mondial - I'll mess around with the long wire again this afternoon.

Thanks for the input Warren - I'm not real concerned about the shortwave.  I've been reading that there isn't a whole lot on there these days, but would like to get it working.  Obviously I want the FM to work.  I'm anxious to get the tube tester later today and test the FM RF amp tube.

Rich

[jcassity]

speaking to SW, my philco is set to pick up a tad below 9.3 to a tad above 15.5k,
there is **A Lot** still out there., and nothing has changed, weather and time of the day still plays a roll.
just got china, they are playing old USA radio shows from the 30's to supplement teaching english.

On my Hallicrafters, it goes from 1.8k to around 38k,, and that all american 5 is picking up a whole ton more!

so ,, its worth setting up.