Philco 650 Very Poor Short Wave Reception - Printable Version
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Philco 650 Very Poor Short Wave Reception - Guest - 04-12-2008
It appears there is a short between the primary and secondary of the SW antenna transformer, but I have not located it. Rider Vol. 6-37 thru 39 shows 53 ohm secondary, but mine uses different transformer part numbers than Rider shows. Anyone have detailed coil info on Antenna trans #38-6915, RF trans #38-6916, and Oscillator trans #38-6917? (Some Rider Philco info has coil alyout and terminal orientation, but not for the 650.) These are the ones installed in my unit. I aligned the radio and it does track very well - just very weak reception.
- BDM - 04-13-2008
I have these transformers on my 640. Not sure what my 650 has due to the fact I cleaned them and erased the part numbers. If you want, I'll test my 640 transformers. Not sure if this 640 worked as I bought it for parts though the chassis is clean & complete.
This set is a hot performer once working properly. I can listen to SW without an antenna on mine though not very well.
- Ron Ramirez - 04-13-2008
I suggest you begin with a thorough cleaning of the band switch with a good contact cleaner, using a toothbrush if necessary to carefully scrub all of the contact points.
Dirty band switches frequently cause poor reception.
After spraying, rotate the switch through its four positions several times, then let dry before applying power.
- BDM - 04-13-2008
Good point Ron. I ran into that on my 650 involving the PB. It gave me fits until I had it cleaned thoroughly.
Philco 650 SW Weak Reception Cured! - Guest - 04-15-2008
Thanks Ron and BDM, for your suggestions. Ron, even though I had "cleaned" the band selector switch with a quality contact cleaner/lubricant, I still did more of what you suggested. You have much more experience than I with this. I used a different kind of cleaner and the a toothbrush with a "haircut" (I had cut the bristles short so it would pass between very close switch wafers.), but with little or no improvement. I used a contact burnishing tool (I'm retired from the telephone company and we used this tool to burnish relay contacts.) with still no help. Still convinced that I was onto something, I "flexed" the movable rotary contact fingers on the third switch wafer and, "Voila!" Something happened! It turned out that the rivets connecting the front side contacts to the rear side contacts were intermittent and when flexed, contact was restored. There were movable tabs on both sides of the wafer, but they hod no electrical contact because they performed separate functions, but at times met the same switch contact finger. The solution was to solder a short wire from the front side to the rear side and now she "runs like a scalded dog," to use a typical NASCAR expression! Thanks to all who have scratched their heads on this problem and especially you who have responded. May God bless your day!
- BDM - 04-15-2008
Congrats! Sensitive radio eh
