Lafayette Wisconsin

[Simon123]

Hello!

I have this Wisconsin CB radio, but i dont know if its FM or AM?
I think its AM, but im not shure?

Thanks

[Richard Crowley]

It would be easy enough to see on most any old oscilloscope.  Are there other people on CB in your area?  You could just try it on the air and let the people at the other end tell you first-hand.

[dr.diesel]

Although not my area of expertise, I don't believe they ever made FM CBs.  At least in the states only AM is allowed via the FCC.

[Simon123]

Thanks
I cannot test if its am or fm because i need to fix something with mic preamp and speaker amp first.

[Richard Crowley]

Although not my area of expertise, I don't believe they ever made FM CBs.  At least in the states only AM is allowed via the FCC.

I thought that also until I read the Wikipedia article which mentioned not only AM and SSB (here in the USA), but also FM in other countries.
http://en.wikipedia.org/wiki/Citizens_band_radio#Frequencies_worldwide

[TheBay]

UK was FM, im sure I've seen the Lafayette brand many years ago, but not familiar with that model. Pop the lid off and post some pictures on here.

[Simon123]

Here they are.
The second picture shows area im repairing. Audio amp was shorted and some other components let the magic smoke out.
https://lh3.googleusercontent.com/-tXNKJELyd0c/VGn1AvA1c2I/AAAAAAAAAWY/AF85ADHEkKU/w958-h719-no/DSC01237.JPG
https://lh6.googleusercontent.com/-GR-fSauKEsQ/VGn1AWBhCwI/AAAAAAAAAWU/f4oT4A4F4DE/w958-h719-no/DSC01238.JPG
PLL is LC7131, mixer is KIA7310

[TheBay]

Here they are.
The second picture shows area im repairing. Audio amp was shorted and some other components let the magic smoke out.
https://lh3.googleusercontent.com/-tXNKJELyd0c/VGn1AvA1c2I/AAAAAAAAAWY/AF85ADHEkKU/w958-h719-no/DSC01237.JPG
https://lh6.googleusercontent.com/-GR-fSauKEsQ/VGn1AWBhCwI/AAAAAAAAAWU/f4oT4A4F4DE/w958-h719-no/DSC01238.JPG
PLL is LC7131, mixer is KIA7310

That's AM (SW Band)

[Simon123]

Thanks. 

[TheBay]

Thanks. 

A few years old that, has to be late 1970's

What band CB is used in your country?, if you get it working you should be able to pick someone up even offshore with a big enough aerial

[Simon123]

Some time ago only FM was legal, but people still used AM anyway.
Now both modulations are legal and most truckers are on AM.
Only taxi and church uses FM i think.
I already have FM station, but there is very little activity, when there isn't any skip.

[Simon123]

And by the way does anyone have schematic for this CB?
When i plug in my mike and speak the led modulation graph doesn't move.
When i inject sound into mixer it does work and im a bit lost on this tiny board.

Thanks

[tinytim]

http://cbtricks.com/radios/lafayette/index.htm

[Simon123]

Thanks, maybe i find schematic thats similar.

[Simon123]

I have found maxon jaws 2 that is similar:
http://www.cbtricks.com/radios/maxon/jaws_mark_2/graphics/maxon_jaws_mark_2_sch.jpg

[Seekonk]

I used to work at a Lafayette service dept in my college days.  Was there when the bottom fell out of CB.  The store managers were screaming for more CB stock.  The owner said his computer programming indicated the market had reached saturation.   Sure enough, three months later you couldn't give them away.  When did they finally fold up?  For those looking for FREE downloadable test equipment manuals there is BAMA.  Haven't been there for a while.  A google search for boatanchors manuals should bring it up.

[Simon123]

Thanks!