Working on Philco 46-350 radio
Posts: 22
Threads: 1
Joined: Jul 2011
Thanks for the response.
One more issue: I replaced all the capacitors and resistors today and found that this radio deviates from the schematics some. For instance the schematics call for two 1M resistors. There is only one 1M resistor on my radio and it links pin 4 on IT4 with pin 4 on 3Q5.
Here's a pic of the area I'm talking about with the resistor circled. This was taken before I modified it.
Posts: 336
Threads: 13
Joined: Apr 2011
City: Montreal, Qc
Something that comes to mind about your radio is the production year.
46-350 was produced while the war was ending. I am thinking that parts might have become scarce and "close ennough" replacement put in place.
Keep in mind that the value rarely needs to be super precise.
Something else, maybe you have a variant of the radio, with alternate schematics? some models had 2-3 variants...
I am no experts on that, others might have a better answer than me on this.
-Mars
Posts: 22
Threads: 1
Joined: Jul 2011
Thanks for the response.
Evidently, this was the variant that wasn't a good idea since it doesn't work at all. But I replaced everything I found the way it was in the radio so hopefully it will work once I get the can capacitor in there, which I'll be doing today. Since it mounts differently, it will require a little bit of modification and an insulating plate since the case itself seems to be negatively charged instead of a wire lead inside of it like the old one.
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
Pin 4 on the 1T4 is being used as a tie point, there is no element of the tube connected to it. Pin 4 of the 3Q5 is connected to the B+ supply and a convenient tie point for one end of the 1 meg resistor. From pin 4 of the 1T4 the schematic I have shows a connection to the pin 2 of the 1U5 which is it's plate. If your set has an additional 1 meg resistor andit looks like the original , then follow what is in your set. Production changes and substitutions were not always documented, and has been stated, this particular change would probably not matter all that much.
Posts: 22
Threads: 1
Joined: Jul 2011
Cool, thanks.
One last question before I power this on (with the assumption that this works):
I have 3 pins on the power switch. If I were looking at it with the pins in my direction and the knob pointed downward, which pins should give me continuity? Pin 1 and 2 give me continuity but only with the volume down low (just right after the "click"). I can't get continuity on pin 3 with any of the other pins with the knob in the "on" position.
EDIT: Forgot to say that the continuity was received with everything hooked up to the pins.
Posts: 22
Threads: 1
Joined: Jul 2011
Well after all that, I still have nothing. No sound, no clicks, no nothing. The 117Z3 tube lights up and that's pretty much it.
Anything else it could be?
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
My last post evaporated somehow. Take a look at the 48-360 Riders. it's pretty much the same set. You can lose the battery terminal and it's troublesome interface switch pretty easily. If there is any good portion of the on-off switch, you can use to connect one leg of the line cord to the plate of the 117Z3, and the other side to the B- and be done with it. Everything else should fall into place soon.
You will make sure that the least (end)part of the B+ is about 8.5 volts (and measure this with about 150 ohms or so load. just 2 watts and use ohm's law to cobble together a suitable kludge.) with the remaining tubes NOT in the set. If all is well, power down, replace the tubes, remove the kludge , and let us know what is happening. You will not harm anything if you put another 100 ohms in series to tame the filament voltage further. Object here is to not burn out the filaments whilst getting other things in order.
Posts: 22
Threads: 1
Joined: Jul 2011
Once again, my radio deviates from the original schematic as far as the power input goes. You mentioned linking one end of the line cord with B- at the switch. I see this on the schematic, however, B- and A- do not run through the AC/DC switch on my radio. They connect directly with the line cord at another location. This has me a little confused so I drew a schematic of the power input for my radio. See if you can make any sense of it.
And, I'm kind of sorry but I don't really understand your second paragraph. I don't know what a kludge is.
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
The A- and B- are the same on this radio and connect to one side of the incoming connection with the AC Line. The other side should be switched with the on off control whichever works and go to the plate of the 117Z3. Everything else can be removed, such that the set would be wired as if batteries did not exist.
Think you're most of the way there but proceed with caution.
Posts: 22
Threads: 1
Joined: Jul 2011
Well I'm at work right now and can't do any testing right now but to remove it so the battery section wouldn't exist, I could remove the A-, B-, B+, A+ wires (and battery plate) and then defeat the AC/DC switch by linking the two orange wires together at the switch and link the two brown wires together at the switch and that should defeat the whole battery mechanism, correct?
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
Almost there, but really what I am suggesting is that you bypass the entire ac/battery switch.
Do this one connection at a time.
You can then remove the interlock, switch and battery plug from the set.
Then bypass the on/off switches on the volume control. Don't mix them up.
Once you have done this, you can use one of the on/off switches on the volume control to make or break the connection from one leg of the AC line to pins 3 and 5 of the 117Z3. Leave the other leg of the AC line where it is.
If you skip these steps the 117Z3 will remain lit as long as long as the set is plugged in.
Again see the 48-360 on Nostalgia Air, it's nearly the same set but the schematics are clearer.
Posts: 22
Threads: 1
Joined: Jul 2011
I've completed the AC/DC switch removal process so far. I connected the brown wires together and the orange wire with the 2.2k resistor (which then goes to the 117Z3 tube) and sealed them up with heat shrink. I then completely removed the switch, the capacitor that grounds to the chassis from one of the battery pins, and I also removed the battery wires.
So far nothing has changed but I'm going to bypass the power switch tomorrow as advised.
Two questions:
When I run the line wire into the power switch instead of everything else that's in there, do I lose the ability to use my volume control?
Also, I've heard that the chassis on these things can shock you (by design), but is it normal for it to only shock you when the power switch is off but not when the power switch is on?
EDIT: I had that backwards. I get shocked only when it's on. Not when it's off which makes a lot more sense. If I switch the polarity on the plug, I don't get shocked at all though.
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
The dual power switch (S2 on the schematic) on the back of the control has nothing to do with volume adjustment (R4 on the schematic) and is not electrically connected to it slyhough they are ganged together. After you bypass the switch connections you can use either one to handle the AC supply. Test the switch you want to use first, one of them might be defective.
Do not touch the chassis when power is applied. All transformerless radios are dangerous no matter how you plug them in. If you use an isolation transformer you are a little safer, but still don't touch when power is applied.
Posts: 22
Threads: 1
Joined: Jul 2011
Well this unfortunately didn't fix the issue either. I tested both sides of the switch when I took it out and continuity seemed to be good on both sides. I actually linked both switches together when I ran new wire to make sure I got one that works. I bypassed the wires that were in there and ran new wire for the line cord. The 117Z3 tube continues to just light up and that's about it. Could this tube be bad? Any other ideas? Feel free to stop the advice any time. I realize I've been bothering you a lot for help but I really do thank you and I've learned a lot about this radio because of you guys.
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
Well we're almost there, and I do need to take a break, but you should confirm that you are indeed developing both the B+ voltage of 90 volts, and you are also developing 8.5 volts to light the filaments. If you hear anything at all from the speaker it is a good sign.
Users browsing this thread: 1 Guest(s)
|
Recent Posts
|
GE Model P-975F
|
There are 2 of these on ePay and several pics on Radiomuseum. Although the front looks like a very popular Hong Kong ra...MrFixr55 — 09:26 AM |
Rare zenith 6s137 restore
|
Hi Fred,
I get things to work, but what you, Russ, RadioSvit and many others on the Phorum do with cabinet and chassis...MrFixr55 — 09:02 AM |
PT-6 antenna connections
|
Hi Bridcarl
+1 on the others. Pin 6 of the 7C6 is the AVC Diode so it is appropriate that that pin 4 of the coil con...MrFixr55 — 07:30 AM |
462ron
|
Joseph, this is beyond awesome. A lot of thought and engineering went into this and you hit a home run! Now I must save ...462ron — 07:27 AM |
Cannot Adjust an IF Transformer’s cores
|
Outstanding work indeed. I wish I could come up with solutions like this.slford310 — 11:16 PM |
Cannot Adjust an IF Transformer’s cores
|
The abilities of our 'Phorum Pholks" never ceases to amaze me! Fantastic fabrication, Joseph! I'm waiting now for...GarySP — 08:27 PM |
PT-6 antenna connections
|
Thanks. I never realized that was a notch noted in the schematic as described. I’ll recheck my wiring.bridkarl — 08:13 PM |
Cannot Adjust an IF Transformer’s cores
|
Thank you! I was quite new to the Phorum when I started this post, so I feel like it might be advantageous to publish a ...jrblasde — 08:07 PM |
PT-6 antenna connections
|
Notice in the schematic the notch at the bottom of the antenna coil is between pins 3 & 4.
Yes, pin 6 of the 7C6 is...RodB — 07:34 PM |
bridkarl
|
I have two PT-6 chassis. On both there is a blue wire that runs from the above chassis transformer to pin 6 of 7C6. So t...bridkarl — 07:23 PM |
Who's Online
|
There are currently 3605 online users. [Complete List] » 3 Member(s) | 3602 Guest(s)
|
|
|
![>](https://philcoradio.com/phorum/images/bootbb/asb/right_arrow.png)
|