I'm new here.Howdy. I have a model 60(late style wiring) and did the recap, including bakelites, all out of spec. resistors, coil resistance check, etc.Broadcast band is fine, sharp peaking on IF cans, all seems well over the band.HOWEVER, the "police band" is dead,dead, dead.I cant find the reason.Antenna coil primary was open and I wound (in the right direction)with #30 and matched the resistance to the drawing.Other coils appear fine.I even have another chassis that I compared with.Checked the mica trimmers, bandswitch,etc. All SEEMS fine, but I need a Philco expert (Mr. Rameriz) to sort me out.
Thanks,
Tom[/b]
Posts: 1,703
Threads: 55
Joined: Sep 2005
City: Evanston, IL
Sounds like you have all the bases covered Tom with your restoration, but you will not hear Police transmissions on 30s and 40s sets that have this AM "Police" band.
That small segment of the AM band just above the regular band (1600-1750 or so)
used to be the original Police band back in the 30s and 40s. Now Police are in the VHF and UHF bands with scrambled narow-band FM transmissions.
That band is now part of the expanded AM band (1610-1710). Depending on your area you may hear next to nothing, or occasionally one of the new expanded AM band stations in this newer X-band, as it's called.
Chuck
(One of the other Philco experts.
)
Thanks, Chuck.
I know nothing is on 1650 kc. or up a ways, but the band on the 60 goes from 1500khz -4mhz., and even with a signal generator cranked, there is nothing.However, if I turn on a work light with a dimmer, there is plenty of hash.
Tom
Posts: 13,776
Threads: 580
Joined: Sep 2005
City: Ferdinand
State, Province, Country: Indiana
Hi Tom, and welcome!
Sounds to me like your oscillator is not running on the "police" band. Did you rewind the oscillator coil primary? And if so, did you use the same number of turns, wound COUNTER-clockwise? The oscillator coil in the 60 is a bit more "finicky" than many other Philcos of this era. I have the specs for the number of turns for both coils around here somewhere (when I rewind a coil, I write down the number of turns and such for future reference).
The primary of both antenna and oscillator coils should be wound with 38 gauge wire; the secondaries (if needed) usually get 32 gauge. #30 would probably be O.K. for the secondary, but not the primary.
Check the band switch itself for possible dirt and corrosion. Deoxit is the best for cleaning these.
Another possibility is moisture absorption in your oscillator coil. You may have to remove it and literally bake it in the oven for about 1/2 hour at 200-225 degrees F. Models 19 and 89 are especially susceptible to moisture absorption in their oscillator coils, but it can happen to any set.
--
Ron Ramirez
Ferdinand IN
Ron,
Thanks for the help. I did not rewind the osc. coil, since the resistance measured o.k., and it works well on the standard band.Maybe I will remove it and check for the corrosion problem you have mentioned on the website. Another guy said maybe the 6A7 is not able to osc. on the 1.5-4.0 mc. band. I'll substitute that first.
If I get it going I'll post the solution.
Tom
Posts: 49
Threads: 5
Joined: Oct 2005
Hi Tom,
Do you have a signal generator that you could set to a few test frequencys in that range and loose couple to the radios antenna? Also do you have a fairly decent lengh of wire attached for an antenna?
Just a few thoughts...........
Jerry,
Yes I have a generator that I coupled thru a small capacitor.And for antenna,I tried my 75Ft. outside antenna,nada.
On a suggestion, I exchanged the 6A7 for another tube and got some signals on the low end of the 1.5-4 mc. band, so I think it may be the osc. coil,wire layout, or a 6A7 with internal capacitance or gain problems.
It is a strange one...
Tom
