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Help with Troubleshooting on a Philco 71
#10

Hey Jon,

As a beginner first starting out, early '30s radios are going to be a lot of guess work for you (voltage & resistance wise) because of the "limited" info on *All* schematics. You're goin' have to get use to it if these are the years you prefer.8)

As you get more restorations under your beltIcon_smile like a lot of forum members here have, you become accustom to what certain resistances (ohms) should be from most coils (oscillating transformers). Bob Anderson had to make some of these assumptions when fixin' his Brunswick 5KR.

Philco IS Very Good in the late 30s & early 40s at labeling their schematics better. Better Than Most at the time. Coil terminal #s & ohm values between each pair of terminal windings. Anything with more than 4 terminals you practically have to pull the whole coil out of the radio to see what terminals are paired with each other to get a good ohm reading.

At this point you can visually inspect the coils & hopefully IF there is a break it is right by the terminal to where it Was soldered. Acid flux over the years ate away at this small diameter enameled wire.

The leads (wire) going to these small value ohm coils should at least be unsolderd to get a Good ohm reading, that a Noob would be comfortable with. Just like resistors, if over in value change them., under in value, need to disconnect one side to get their true value.

Now there are goin' be some that will tell you that you don't have to disconnect the coils to get That True Reading that you can be confident about, & that maybe true if you're a veteran at these, but they forget what it was like when they were a noob, And....

If YA All don't believe me,
Just take a looksey at Bob's last video on his 15DX.Icon_smile He disconnected one side of the shadow meter so he could get an accurate reading. John(badrestorer) also done that on the shouldered tombstone he re-did.

I've been switching 3 of them around, on these 3 650Bs this last week. One Was OpenIcon_sad All 3 were wired in differently. All produced under code 121.Icon_wink

Gotta Love PhilcosIcon_thumbup
Lloyd
_____________________________________________________________

Ooohhh Noooo, What’s the Matter NOW?? It WAS Working GREAT before I “FIXED IT”!!


Messages In This Thread
RE: Help with Troubleshooting on a Philco 71 - by CrumblingWires - 08-04-2012, 11:48 PM



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