[gregb]

  I have 2 40-150radios that work perfectly on the broadcast and police bands but nothing on shortwave. The oscillator coils check fine but nothing. I am I missing something here or what? Anyone have any ideas?
Thanks

Greg B

[pbert]

Please see the post from Raleigh on 3-17-2015, It has the information that may be helpful.  I am also starting work on my 40-150 set. Good Luck .

[klondike98]

Here's the link to the thread that I think pbert is referring to:
http://philcoradio.com/phorum/showthread.php?tid=11011

[gregb]

Here's the link to the thread that I think pbert is referring to:
http://philcoradio.com/phorum/showthread.php?tid=11011

Thanks! Its just so happens that one set uses the loctal socket and the other uses the octal version and they both have the same problem. I will try the socket first and see what happens. We are lucky here in that it is so dry we never have to worry about moisture issues unless it was outside in the rain. Anyone know what the problem with the socket could be? I understand if it was a moisture issue but we don't have that issue here.

Gregb

[gregb]

So I have changed the socket, there was no apparent issue with it. The new socket made no change in the shortwave so I guess I will pull the coil and bake it in the oven and see what happens with that.

Gregb

[David]

This set may have been modified during WW2 so that the SW band would not work. This was common practice on the west coast of America if you were from Japan or China or related. Take a close look at the selector switch. Good luck David  

[gregb]

Well I just reinstalled the coil after baking at 150 deg for about an hour an a half, no change. The coils all ohm out ok and the switches are all wired right and still no shortwave. I think I have to put this one aside for a while.

Gregb

[Arran]

 There might be a defective mica cap in the shortwave oscillator tank circuit, sometimes that will kill it.
Regards
Arran

[Ron Ramirez]

Question: Is the SW loop connected? (It's a single turn loop mounted under the top of the cabinet.)

[gregb]

 There might be a defective mica cap in the shortwave oscillator tank circuit, sometimes that will kill it.
Regards
Arran

There is a mica and I swapped it with a new one and no change.


Gregb

[gregb]

Question: Is the SW loop connected? (It's a single turn loop mounted under the top of the cabinet.)

I have tried with and without it connected and no change.

Gregb

[fifties]

On my 40-180, which is basically the same chassis, one lead of the SW loop connects to the solder lug mounted on the top right side (looking from the back) of the tuner, and the other to the right most antenna screw connection on the back of the chassis. Is that the way you tried yours?

You might also try a random length wire at either point, with the radio tuned to 2.5 Mc (WWV), or in Canada I believe their time frequency is about 3.3 Mc.

[gregb]

On my 40-180, which is basically the same chassis, one lead of the SW loop connects to the solder lug mounted on the top right side (looking from the back) of the tuner, and the other to the right most antenna screw connection on the back of the chassis.  Is that the way you tried yours?  

You might also try a random length wire at either point, with the radio tuned to 2.5 Mc (WWV), or in Canada I believe their time frequency is about 3.3 Mc.

I have tried the shortwave antenna with no change. The low band shortwave works just fine its the high band that won't work. It seems really strange to me that its both radios with exactly the same problem using two different tubes. Its got to be something really simple that I'm just not seeing.

Gregb

[Raleigh]

I don't know if you tried measuring the resistance across the coils. After I baked my coil, I measured the resistance across the coil and noticed that it was very high between all or almost all of the pins on the coil. Tens of ohms instead of less than one or two. I looked at the connections between the magnet wire and the terminals with magnification and good light, and nothing looked bad. On a whim I decided to reflow all of those connections with fresh solder. Afterwards none of the resistance readings came down as low as they should have been, but all were at least in the low single digits.

It worked on all three bands when I put it back in. Unfortunately I didn't test after baking and before reflowing, so I can't say which trick worked.

It could be that your problem is entirely different, but if you measure the resistance between all the pins and find it anywhere near, say, 10 ohms or over, try to reflow the connections. Maybe use some liquid rosin flux if you have any,

It seems to me that I had to reflow a couple of the connections a few times before I got them as low as they would go. I'd reflow once and notice the resistance had come down a lot but not nearly as low as it should be. Tried again, and it'd be lower, and again until it didn't get any lower. I think there were one or two connections I never did get below 5 ohms, but it still worked on SW.

[gregb]

I have them both working now and they seem to be working well. They even get shortwave reception with no external antenna connected.
On the first one I tried baking the coil, reflowed the solder, checked and double checked the wiring and switch and with no positive result. One of the local old time radio repair guys said it was critical as to how the antenna's were connected for this series of radio to work properly so I focused on that. When I got the radios in they each had no shortwave antenna attached at all and only one or two wires attached to the main antenna.
Once both the main antenna and the shortwave antenna were connected properly the shortwave came to life on the first radio so I reattached the missing wires to the second one and got them all connected up properly and away it went. This is the first set I have ever seen that the way the loop is connected would effect the shortwave so much.

Gregb