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Philco 89B won't oscillate!
04-13-2016, 10:41 PM
From following the schematic, that tickler coil is open. It's supposed to be 5.2 ohms per schem. Nowhere to be found, although the others , well one reads 5.7 ohms. The other has a reading that looks to be charging a cap. Reading keeps on raising.
SM
04-13-2016, 10:43 PM
Time to pull the osc coil and rewind the feedback winding it's open.
Terry
04-14-2016, 01:53 PM
O-coil pulled. Feedback winding is definitely open and not on the ends! The other 2 windings are okay. Anybody know what number magnet wire I'll need to rewind?And where to get the new wire?
SM 
04-14-2016, 02:13 PM
Radio Shack. If it is still open in your place.
Internet. Ebay. I usually just measure the diameter with calipers then determine the gauge. Then buy. 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.
04-14-2016, 07:10 PM
Original was 38g but it isn't real critical. Have used 32-38g with good result. As Mike said RS carries a pak of 3 or 4 different sizes in one pak.
Terry
04-14-2016, 09:15 PM
I bought size 36, so this is going to be an adventure! I've never done this before! That wire is thinner than a hair! I broke it just trying to clean the wax off with naptha! The other 2 main windings measure 5.7 ohms and 5.0 ohms just as the schematic says. I'm in over my head, but I won't drown!
SM
04-14-2016, 09:30 PM
I'm pulling for you. You can do this. I have did two coils just take your time.
04-18-2016, 01:45 PM
I have decided that I don't want to mess this O-coil up, so I've decided I will send it out to a competent rewinder. Anybody know anyone that will take this job?? If so, PM me and we will talk. Thanks in advance.
SM
05-02-2016, 04:03 PM
Yup! A fellow from Canada helped me out and now, my 89B oscillates! Er, but it won't quit oscillating. Just one tone that rises in volume and note nearing the top numbers. And that is with all tube shields on. Anybody else ever hear of such a thing? But at least it's no longer silent! Fun, fun, FUN!
SM 
05-02-2016, 05:38 PM
Steve, I merged your "89B Does oscillate" thread into your original 89B thread to keep the topic together.
05-06-2016, 02:09 PM
I have been forced to pull the new oscillator coil- nothing but parasitic noise. Now, I'm nowhere with nowhere to go. I'm done.
SM
05-06-2016, 02:24 PM
Steve, merged your new thread into the original 89B thread. Please see your PM.
05-06-2016, 04:53 PM
OK, just a thought here. The direction the coil is wound in is critical. If wrong direction is a possibility, try switching the leads and see if that helps.
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