DX959 only tunes in 2ch steps. tune ch 40 frq disp reads 27.405( 40)radio tx and rx on 40. tune down to 39,frq disp says 27.405 not 27.395(39) rx and tx on 40. tune down to 38 and frq disp says 27.385 (38)radio tx and rx on 38. this problem continues down the band untill the low 20's. ??? IC3? tune sw?? radio IS properly aligned
Radio Communications - Galaxy Radios - DX-959 40-Channels Base CB Radio
Answers & Comments
Has this set been modded?
there is a lot that you can do to this unit
http://www.cbtricks.com/radios/galaxy/dx959/index.htm
Without modifying the radio the best thing is to use a good aerial and try and keep your coax as short a possible...
However if you are looking to modify the output circuitry then there is a mod to change the output to a dual mosfet like the dx2517...
http://www.worldwidedx.com/tech-repair/27179-dx959-new-mosfet-version-dual-final-mod.html
There are more mods and schematics available from here:
http://www.cbtricks.com/radios/galaxy/dx959_mosfet/index.htm
Have you bought your radio yet, there are sites that sell fully modded radios for around $380...
http://www.customcbradios.com/catalog/item/6636015/6546885.htm
If this information has been helpful please click Fixya!, it is the only way I am rewarded for my time
Hi and welcome to FixYa,
I doubt if it is the 8719 PLL (IC3 though of course it is still a possibility) since the display also shows 27.405 / 40. Common to the PLL and the display would be the rotary selector swtich.
A way to eliminate the PLL as a suspect is to check the logic state on pins 10(P6) - 16(P0) programmable inputs.
The above assumes that no mods were added to the Galaxy DX959
Good luck and thank you for asking FixYa.
Appreciate your postback.
To my understanding, the clarifier mod (analog) would not have an effect on the channel selection (digital). I would still suggest to check the logic state on pins 10(P6) - 16(P0) programmable inputs. Additionally, check the 1K X 7 resistor block as its purpose is to 'pulldown' the programmable inputs to logic 0
Hi again,
You could of course temporarily remove the clarifier mod just to eliminate the remote possibility that it is the cause.
A method of testing logic state; at each channel, the voltages of pins 10(P6) - 16(P0) would change hence the voltages would be different on Channel 40 and 39. If the voltages did not change, then the rotary selector switch is the most likely culprit, fix is to replace. On the otherhand, if the voltages change but the frequency did not, then the PLL is most likely faulty, fix is to replace. Below would be the test points. Please note that the pin between P4 & P5 is constant 8 volts. Further below would be the section of the schematic relative to the programmable inputs.
Cheers.