DX-949 no power output

[Rolling Thunder]

I did a lot of research (or so I thought) before making the modifications to my DX-949 and now I have no output at all. I followed the instructions from firebreather about removing Q39 and adjusting VR14 and so on... After firing up the radio, I realized that the power meter and SWR meter are going straight to zero when keying up the mic. So, after digging a little further, I realized that this 949 has the EPT069611A (supposed to be in the DX939) board and not the EPT06960Z that everybody thinks it does. My question is this, will removing the Q39 transistor cause the problems that I am having, or is something else really screwed up? Thank you in advance.

 

[9C1Driver]

Sounds like you jacked it up, I would put it back the way it was, give it a proper tune and alignment and be done. Extra channels and an unlocked clarifier would be the only "mods" needed for that radio.

 

[CbRadiosPRONTO]

To answer your question: No. Removing Q39 will not cause the radio to have no output. The boards you're referencing are essentially the same. Theres a possibility that when you removed Q39 (assuming you de-soldered it), you accidentally soldered together two solder pads or pulled a pad up (damaged a trace). If you messed at all with r264 by installing a "swing kit" (resistor/diode combination), it's possible that you put the diode in backwards.

Not knowing what mods you attempted makes it difficult.

 

[loosecannon]

you should put Q39 back in. it's a 2SC945 transistor in case you didnt save it.

removing that transistor will cause the SSB to sound like crap.

if you did research, forget whoever told you to do that. it is a crap mod.

all you need to do in a 949 is turn up the modulation pot.
if you want to go further, you can do an NPC mod, but not the one that uses R264. do the one that uses the diode and a 100ohm resistor in series.

now, as far as having no output, let's start simple. you did replace the bias board right?
that little PC board right in front of the driver and final?
make sure its in place.

if it is, measure the DC voltage in AM mode on that little board. put one lead to PC board ground (any tuning can shield), and one lead on the bias board.
turn the external RF power knob all the way up, and measure the DC voltage in transmit mode.

if you have no voltage here, chances are Q54 is bad. if so, replace it with a 2SB817 or 2SB827 or something similar. also check Q55 right in front of Q54. Q55 looks just like the driver and final transistors. if Q55 is bad, replace it with an NTE153 or similar.

if you do have voltage here, tell us what that voltage is, and we'll go from there.
LC

 

[nomadradio]

Never ever looked at Firebreather's mods. Any time you refer to a resource you found on the web, including a hyperlink to it would serve to explain a lot.

Ditto on Q39. We put that one back in mostly to prevent SSB transmit from melting down the final and Q54. The nasty sound is only a bonus if you transmit on sideband with Q39 pulled out. Risk of a mushroom cloud is the real reason to put it back in, IMHO.

I would look for a solder bridge. Any time a simple modification leads to a total shutdown, that's my first suspicion. Have a good look at the solder side of the pc board with a bright light and magnifier. Just one tiny splash of melted solder falling off the tip of the iron can do this if it lands on the pc board and bridges across two adjacent solder pads.

Of course you'll never guess how I learned to check for this.

73