help with galaxy 959

[grandpaclint]

ok here goes,,,i have this 959, when i got it from sparkies almost 2 years ago i put it on my base bench, hooked it up, tested everything,,it worked, i even talked on ssb for a minute.

took my present radio,(that was working fine) out of my mobile, installed the 959.....it would not transmit,,,,it received fine,am,ssb, the talkback works.
took the 959 back in to the base,,,hooked it up,,same thing, no transmit, every thing else works.........put the other radio back in the mobile, all worked like it should....low swr etc...

i dont need a lesson on antennas,,,,or how to hook up a damn cb, i have been doing it since the 60's.........all i want to know is where and what to test in the 959,,,,i was told they were rather fragile, if that is so, they shouldnt be put in a mobile.

2 years ago after all that i put it back in the box and put it on the shelf.
i tried to contact galaxy,,no luck there.

any help i can get will be appreciated, needless to say,,not all that happy with galaxy.

 

[Robb]

The most common reason for no output is a failed final or driver transistor.
Any brand/model of radio can have this kind of failure.

If you have a Digital Volt Meter, then I suggest you check the gate voltage on the driver (Q49) and final (Q47) if they are MOSFETs for ~4v.
If it is an older radio, it will have bipolar transistors and the driver bias should be set at 50mA and the final bias should be set at 100mA.

That is for starters.
You still need to test the driver/final with your DVM, and that will require de-soldering them from the board first.
HOW TO TEST YOUR TRANSISTORS WITH YOUR MULTIMETERS

If you cannot do all of that because you don't have the equipment and cannot locate the parts; then send it to a shop.

Galaxy Radios DX959 Service Manual
http://www.cbtricks.com/radios/galaxy/dx959/graphics/dx959_ept069610z.gif

 

[grandpaclint]

i thank you so much, at least someone gave some info. as to what to check.
i was just out in the man cave, had the 959 hooked up,,i have other cb's on the shelf
i turned one on,,,i test on channel 3 here,,,,,keying the mike on the 959 ---no carrier at all, however the other radio did pick up my modulation, faintly but i could hear myself on the other radio......the meter would swing upward when i talked....very interesting.
the test points you mentioned,, are they the finals???? i have no problem testing them
as i have a dvm......i can see no numbers on either of them...
but now i at least have a starting point

Thanks
Clint

 

[Robb]

You will need to identify the part #'s on the driver and final.
If the radio has bipolar transistors there instead of MOSFETs, they will read 2166 on the driver (Q49) and 1969 on the final (Q47).
That is the first step.

If you are hearing audio on another radio, it well could be that either the driver or final has failed.

 

[9C1Driver]

I would also do a quick double check on the radio settings and try a different mic. Some time it's a simple issue like that. Sounds like your antenna systems are good to go. I hate it when something like that happens. Keep at it, hope you get to the bottom of the issue.

 

[grandpaclint]

i have tried other mikes,,elimated that problem early on. i'm checking the finals today
will keep you posted...i cant thank you enough.

 

[ExitThirteen]

I'd also look for any solder joints that might be suspect. Those radios have been plagued with poor solder joints for quite some time. Don't be afraid to push down on the PCB while in TX mode to see if you get it to TX... seems a bit odd that the radio would just quit transmitting all of a sudden.

~Cheers~

 

[Ranier1315]

I'd also look for any solder joints that might be suspect. Those radios have been plagued with poor solder joints for quite some time. Don't be afraid to push down on the PCB while in TX mode to see if you get it to TX... seems a bit odd that the radio would just quit transmitting all of a sudden.



~Cheers~

^^^^^^this^^^^^^^

Galaxy is prone to bad solder joints. I have had my DX95t2 apart 4-5 times for the same thing. It seems to be really sensitive to temp changes which is a BIG problem for a radio that is mounted in my Jeep.

 

[grandpaclint]

You will need to identify the part #'s on the driver and final.
If the radio has bipolar transistors there instead of MOSFETs, they will read 2166 on the driver (Q49) and 1969 on the final (Q47).
That is the first step.

If you are hearing audio on another radio, it well could be that either the driver or final has failed.

ok i just pulled both q47 and q49,,,both are IRF 520's,,,,mosfet, i looked them up.....on q49 i get no readings,,,,on q47 center to right 26, center to left 26
right to left 2.............although i dont think i tested properly for a mosfet
i'll look that up

thanks

 

[grandpaclint]

i just pulled both Q47 and Q49 they are both IRF 520's, so i have mosfet's
now how to test them?????

 

[Robb]

How to test an RF MOSFET with a digital multimeter - YouTube

 

[tinkerer973WI]

I just worked on a 959 with the exact same symptoms, in this one the test point were not contacting the foil board, failing to get voltage to the driver and final stages..... wouldn't be a bad thing to check either.....

 

[grandpaclint]

right now im concerned with the fet's, i ordered a few, they are cheap.
i'll replace them soon as they get here, and go from there.
i also have a voyager9000 with the same problem,,seems like these newer cb's
are a bunch of crap,,,,,i have some johnson messengers that work just fine and have for
what??????40 some odd years.....

thanks guys for the help

 

[The Jerk]

,,i was told they were rather fragile, if that is so, they shouldnt be put in a mobile.

I ran one for about five years, and probably 350,000 miles in a pickup. It never gave trouble..
HOWEVER...

Mine was boogered right out of the box too...I took it to a shop to ve fixed, so I'm no help. It never gave any trouble from there out.

Sent from my SAMSUNG-SM-G730A using Tapatalk

 

[grandpaclint]

unfortunately i have no cb shops near here in kingman az. and from my past experience
with places like sparky's, its probably a good thing i dont have anyone here---lol