galaxy dx2517...messed up

frogman296 · Post by **frogman296** » Friday 5th Sep 2008, 7:42

this radio has no forward power...i replaced the driver and finals...after rebuilding the traces as best i could.....the radio shows modulation, but absolutely no wattage.

as you can see in this pic..i have drawn an arrow to the pot(VR10) and resistor(R241) that was smoking when the radio was powered up

i have replace the resistor and pot...all the diodes in front of the driver and finals...the diode in front of the "middle final"(Q48) is showing continuity, while the others are not..

i am stuck...the only reason i even attempted this, not for me but for a friend, was because i did not want to ship it. the older gentleman had tried to put the finals in, and whatever he did it caused the radio to smoke VR10 and R241 when powered on...as of now the pot and resistor aren't smoking at all...everything functions fine on the radio, except no wattage on either end of the rf power adjustment.

any help would be appreciated

thanks in advance

i have pics of the final install...but when i posted them it said i was trying to spam...maybe i posted too much?? that was not my intention, just to help explain the problem, and what i have already done.

frogman296 · Post by **frogman296** » Friday 5th Sep 2008, 7:46

before

after

timrim · Post by **timrim** » Friday 5th Sep 2008, 9:24

My god! I see radios come in like that all the time, it just breaks my heart. One guy tried to save money by putting MOSFETs in his radio, the board was butchered so bad, I would not even work on it. Most of the traces in the final area had been completly removed, parts missing etc. His attempt at saving money cost him big $$$.

What finals were in the radio and what finals are you trying to put in? Those diodes may have smoked if you tried to put in MOSFETs instead of original finals, with MOSFETS, the diodes go in differently. Do you have voltage on collector of finals and driver? What voltages are you getting on EBC of driver and finals?

EDIT: It looks as if the right legs of all 3 transistors are connected to the wrong place, I believe they need to be moved left to the broken traces, I will verify that later when I am looking at the proper board layout. I also see a tiny ball of solder that looks like it may be shorting 2 traces (collector and base) of one of the transistors.

frogman296 · Post by **frogman296** » Friday 5th Sep 2008, 9:53

i was thinking that those legs were out of place as well....but...i had to verify...thats the way that the fella had put the new ones in..

2166 driver and 1969 finals....i replaced the diodes, and it still shows continuity on the final closest to the driver

i have no spare 2166's on hand, so i will use a 2078 until i can get a 2166

voltages on the collectors are 6.63, 6.75, 6.75(driver)

is this where you mean the trace may be shorting??

timrim · Post by **timrim** » Friday 5th Sep 2008, 11:10

Here is the board layout, I marked where the transistor leads go.

On your last picture, the ball of solder is just to the right of your red circle about even with the bottom of the circle about half inch.

frogman296 · Post by **frogman296** » Friday 5th Sep 2008, 12:09

timrim wrote:Here is the board layout, I marked where the transistor leads go.

On your last picture, the ball of solder is just to the right of your red circle about even with the bottom of the circle about half inch.

that lil blob was just a lil pece of slag...it wasn't on there when i was testing the radio..

and i do believe you are right...the base legs of the transistors seem to be to the right too much...

frogman296 · Post by **frogman296** » Friday 5th Sep 2008, 14:04

voila....it worked....many thanks timrim...i cant say thank you enough...now i can get this disaster out of here

frogman296 · Post by **frogman296** » Friday 5th Sep 2008, 16:45

the pot that i replaced, was for the bias voltage for one of the finals...when i adjust, nothing happens..

i followed the instructions, on cbtricks, for adjusting the bias voltage...but to no avail..

timrim · Post by **timrim** » Friday 5th Sep 2008, 20:40

Glad you got most of it straightened out, I will look at the circuit tomorrow and see if I can offer any further ideas.

timrim · Post by **timrim** » Saturday 6th Sep 2008, 8:31

Actually its not the voltage you are trying to adjust its the final current. You remove the jumper pc board and connect an amp meter between posts, you need to set the driver current and final current, when doing this go to USB with mic gain fully off.

Final Bias - Connect DC Ammeter between TP7 and TP8. Key TX and set VR10 & VR11 to 0mA. Then adjust VR11 for 50mA. and then adjust VR10 for total of 100mA for both.

Driver Bias - Connect DC Ammeter between TP7 and TP9. Adjust VR 12 for 50-75mA

If you are unable to properly set bias, then we can look for a possible fault.

frogman296 · Post by **frogman296** » Saturday 6th Sep 2008, 9:38

timrim wrote:Actually its not the voltage you are trying to adjust its the final current. You remove the jumper pc board and connect an amp meter between posts, you need to set the driver current and final current, when doing this go to USB with mic gain fully off.

Final Bias - Connect DC Ammeter between TP7 and TP8. Key TX and set VR10 & VR11 to 0mA. Then adjust VR11 for 50mA. and then adjust VR10 for total of 100mA for both.

Driver Bias - Connect DC Ammeter between TP7 and TP9. Adjust VR 12 for 50-75mA

If you are unable to properly set bias, then we can look for a possible fault.

i went by the cbtricks instructions...there was no adjustment in either, no matter how i turned them..nothing

timrim · Post by **timrim** » Saturday 6th Sep 2008, 12:43

What is the current at both test points?
It is possible that either the control burnt out again or there is something else in the bias circuit that is blown.

frogman296 · Post by **frogman296** » Sunday 7th Sep 2008, 2:49

timrim wrote:What is the current at both test points?
It is possible that either the control burnt out again or there is something else in the bias circuit that is blown.

showing no current at both test points

timrim · Post by **timrim** » Sunday 7th Sep 2008, 6:39

Ok, just for clarification, make sure:

1.- Your meter is set to measure low amperage 1 amp or 500ma setting if your meter has it, make sure the probe is in the proper socket for amperage, and make sure the protection fuse in your meter has not blown. Make sure your meter is not set to read too high of amperage or it may not pick up the small current we are looking for.

2.- Your radio is on ssb with mic gain fully counter clockwise.

3.- The positive lead of the ammeter goes to the post on the far right, the post that is farthest from the rest.

You should get a current reading once the controls are adjusted some

If you put the jumper board back in radio and actually have power output, there should be some amperage draw from the finals and driver and you should see something from your ammeter, if not, I would suspect a problem with the meter.

If you have verified all the above steps and are sure your meter is actually working on the amperage settings, then we can start do dig a little deeper.

frogman296 · Post by **frogman296** » Monday 8th Sep 2008, 10:34

the radio is working perfectly as of now...i have "road tested" it...

timrim · Post by **timrim** » Monday 8th Sep 2008, 10:48

Glad to hear it, I think perhaps your ammeter was not working, that would explain zero current reading.

DWB · Post by **DWB** » Monday 8th Sep 2008, 12:40

My god man,was that soldering done with a fireplace poker?? Buy some real soldering equipment like Antex.

frogman296 · Post by **frogman296** » Thursday 11th Sep 2008, 15:34

DWB wrote:My god man,was that soldering done with a fireplace poker?? Buy some real soldering equipment like Antex.

thats not called for...and this was charity work...before and after pics were shown, and there was a decent job done on my part.