Posts: 4
Threads: 2
Joined: Apr 2016
City: Traer,Iowa
Old Farmer says hi,
I've been setting the pushbuttons on a 42-390. 3 of them I could tune them into a station quite easily and they work real good. 2 of them, I'm lost ! By now, I've screwed the coil & cap. So many times I don't know where I'm at. The best I could do was a very weak station that you could barely hear. Is there a better procedure other than just screwing back and forth and hoping you can catch something. On the fm antennae jack I see 2 extra holes. That wouldn't be some sort of aid to help set up these buttons? Is there anything that I should be looking for.?
RESPECTFULLY YOURS
Steve
Posts: 5,009
Threads: 267
Joined: Nov 2012
City: Bandon
State, Province, Country: OR
Welcome to the phorum.
I've not set them on that model but there is a service bulletin #398 that has some info. The link to a djvu version is
HERE. the site also has a link to download a browser helper to open djvu documents. There are specific frequency ranges for each of the 5 broadcast pushbuttons so there has to be a good am station in each of the ranges to get something on all of them. its also possible that the coil in the button circuit has broken and that would kill that button.
UPDATE: Here's a direct link to the pdf version of the service bulletin:
LINK
Posts: 4
Threads: 2
Joined: Apr 2016
City: Traer,Iowa
HI Bob,
Thanks for the pdf link. I was getting bogged down trying to get the file the other way.
Tonight I put a wire coil inside the antennae and tried to slowly move the signal generator up and down the frequencys. Nothing, but, I could jam 455 khz through it. I think you might be right about the coils. Time to pull out the chassis and verify the bad news.
Thanks for the advice,
Steve
Posts: 7,214
Threads: 266
Joined: Dec 2009
City: Roslyn Pa
What I've done because sometimes it's hard to tell if the oscillator is running and where it's oscillating is use a counter to watch it. One of those $10 counters with a couple of turns of hookup wire connected to it looped over the osc tube should be able to get a reading.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 4
Threads: 2
Joined: Apr 2016
City: Traer,Iowa
Hello,
I wanted to get back to you and tell you guys what I found.I put 8 loops of #18 wire around the osc. tube. It wasn't enough to get a real accurate reading with my counter, but you could sure tell if it was working or not.. Found the coil & cap. leads on two buttons switched around.Easy fix !!!
Thanks for all the advice,
STEVE
Posts: 5,009
Threads: 267
Joined: Nov 2012
City: Bandon
State, Province, Country: OR
