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Philco 514
#76
Skip, if you make a neutralizing adapter, be sure to make the interconnecting wires as short as possible. The adapter sockets and wires have capacitance between them, so it affects the interelectrode capacitance seen by the circuit.

Perhaps the most accurate method of neutralization is to insulate the filament pin of the actual tube used for each stage, one at a time. This way you are neutralizing the actual grid-plate capacitance of each specific tube and not adding any stray capacitance.

I usually wrap a small piece of clear Scotch tape on one of the filament pins for neutralizing. The tape is thin and doesn't interfere with inserting the tube in the socket, yet insulates the pin so the filament is not lit.
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#77
Ok Thanks.. Parts arrived today. A volume control that measures 9K instead of 65K like mine does.. And the adapters to make a socket for neutralization..

I put the adapters together and will try that first.. I will install the volume control this weekend..

I assume its better to have the chassis back into the cabinet before alignment.. I can access the parts from the bottom of chassis thru the holes provided..

Also most done...

Skip...
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#78
OK tried the empty ball point pen plastic tube holder to align.. it didn't work at all seems its to small. I tried tried to soften it up and mold around nut That didn't work either...

Any thing else I can try?

Skip...
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#79
If this is not a trimmer/padder that is under the plate (B+) voltade AND has to be accessed through a hole in the chassis, you could try to use a socket wrench, after each adjustment removing it and seeing if it changes and then adjusting it again a little to achieve the max, each time removing the wrench until the sig is peaked.
For those inside holes, with power off loosen them fist with the wrench making sure it could be moved without very strong effort, and then use the ball pen tube morfed hot after a nut of the appropriate size first.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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#80
Ok Newer volume control installed. Works good.. Did RF alignment all went well..

Only problem is at 1440 Khz I have a station about 1 mile from me.. it comes in distorted.. No ,matter what I do..

It seems to be overloading the receiver..even with NO antenna connected.. maybe everything back in cabinet will shield it a little..

I did not attempt the neutralizing yet.. I think I will put the bottom plate back on and put in cabinet then check it .. Maybe it doesn't need to be neutralized.. We will see..

Skip...
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#81
Back in the cabinet and an earth gnd connected to it should help.
"Just because the microphone in front of you amplifies your voice around the world is no reason to think we have any more wisdom than we had when our voices could reach from one end of the bar to the other"     Ed Morrow

Terry
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#82
Ok, I will put it together today .. Then see what it does...

More to follow...

Skip...
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#83
Ok, all put together.. Pain to get the phono jack in without it shorting to chassis.

Works very good.. Distortion is gone at 1440 Khz now.. But slightly above that it motorboats.. I know how to fix that by detuning the last RF section..

I will take pictures of the unit and a video of it working..

Thanks
to all for the help to get this 1928 Radio back in working order..

Not bad for a 89 year old radio..

Skip...
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#84
One other quick question.. Did these ever have any feet?

Skip...
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#85
Ok did the neutralization.. Worked good.. Radio is much more sensitive. No more motor boating either..

Just have to button it up and good to go..

Thanks all

Skip...

PS Any answer on feet??
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#86
The original feet were rubber...which is why they are usually gone after nearly 90 years.
--
Ron Ramirez
Ferdinand, IN
Я этого не понимаю
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