Philco 34 using 2A7 on Breadboard
Posts: 240
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City: Boulder, Colorado
Hi All;
Since I have a free day tomorrow and have the Philco 45 Working.. I thought I would play arround with the Breadboard part of the Radio, and Try and see if I take out the 1C6 and with a different Socket I would wire in a 2A7, like what I have in the Philco 45, except the 45 has a 6A7 instead of the 2A7.. And see If the mixer circuit works any better than with the 1C6.. I figure it couldn't hurt at this point.. Before I go and make the change on the Philco 34 itself.. I did find that the Wave Trap was bad in the 34 and have bypassed it and with my signal generator I can get it to receive signals, but even with the same Antenna wire that I use on the 45 It will not Receive at all.. I thought they might be too weak, but the 45 proves that wrong..
THANK YOU Marty
Posts: 13,776
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City: Ferdinand
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Don't do it, the 2A7 is a 2.5V tube for AC receivers, the 1C6 is also a pentagrid converter but specifically designed for battery operation. I think your time would be better spent studying electronics theory instead. One man's opinion, that's all, no offense intended.
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Ron Ramirez
Ferdinand IN
Posts: 240
Threads: 27
Joined: Jun 2013
City: Boulder, Colorado
Hi All;
Ron, No offense taken.. Just looking for a Solution, to making the 34 work, as it is suppossed to be a descent Receiving Radio.. Even if I need to change it some to make it work..
My thought was get it to work somehow then work on getting it to work with its origional tubes..
Since the 45 Came up relatively easy compared to the 34.. So, I am looking for Why it is having so much trouble making the 34 work..
Looking for Solutions and Suggestions on the 34..
THANK YOU Marty
Posts: 13,776
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Joined: Sep 2005
City: Ferdinand
State, Province, Country: Indiana
The solution is not to reinvent the wheel, but to troubleshoot what you have. You have to find out why that 34 isn't working. If all capacitors and out of tolerance resistors have been replaced, and you can pass audio but no RF, then it's time to look at coils. Possibly mica caps too.
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Ron Ramirez
Ferdinand IN
Posts: 240
Threads: 27
Joined: Jun 2013
City: Boulder, Colorado
Hi All;
Ron, it can pass RF from my Signal Generator, but not from the Antenna, its as though the input from the Antenna is too weak.. I can tune it to various places on the Dial, and re-tune my Signal Generator to that place and it picks that up fine.. I have wired arround the Wave Trap as that is open, and since the Signal Generator Signal is getting thru, I am not sure what to look at or for next..
All Paper Caps have been replaced, as have all out of tolerance Resistors, all but one Mica Caps have been replaced and the one that hasn't been replaced is C-5..
http://www.nostalgiaair.org/Resources/185/M0013185.htm
THANK YOU Marty
Posts: 13,776
Threads: 580
Joined: Sep 2005
City: Ferdinand
State, Province, Country: Indiana
Well, then, rather than doing what you have been doing, I would be taking a good, hard look at that antenna coil. I can't look at a schematic right now but if (5) is in the antenna coil circuit, maybe it needs replacing? A 34, 44 or 144 parts chassis may yield a good antenna coil.
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Ron Ramirez
Ferdinand IN
Posts: 240
Threads: 27
Joined: Jun 2013
City: Boulder, Colorado
Hi All;
Ron, C-5 is in the Short wave circuit, I believe.. I have another Coil that is just like the one in my 45, for the Antenna coil, it needs one wire fixed, but I think it could be Subbed in for comparison sake.. It has three coils but the third one is for the Short wave coil that is switched in and out with the Band Switch..
Yes, That was part of my origional thinking that since the Front end (Bandswitch, coils and etc) are the same that I could wire the mixer Tube and Oscillator like the 44..
But, for now I will take a deeper look at the Antenna Coil per Your Suggestion..
THANK YOU Marty
(This post was last modified: 09-20-2013, 11:48 AM by marty.)
Posts: 240
Threads: 27
Joined: Jun 2013
City: Boulder, Colorado
Hi All;
Well, I fixed the wire on the Broken coil that I was going to use as a sub, But then it broke on the other side while I was re-installing the Donut coil on the inside, and it kept breaking closer and closer to the inside, untill there was no more wire to get ahold of..
I have a Philco coil form that is a smaller Diameter than the other coil forms that I have, In fact I took it out of one of my other Junk coil forms, I will wind the wire on it, (new wire) and get the proper resistance since it is the input (Antenna coil) side and mount it inside of the other form.. Then I can sub this for the coil that I have in the Philco 34..
THANK YOU Marty
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