RCI 2980WX No Power out?

[Crambone]

Radio receive is good all modes. Green power lite indicator on front blinks low to high. I can see some modulation on the radios meter in AM only, I also hooked scope to output and verified have modulation on AM but nothing else.
Radio has NO mods is 100% factory.
TP7,8,9 I see 6.3vdc RX & 6.1vdc tx
Q47 & 48 RX
S 0vdc
D 6.3vdc
G 0vdc
TX
S 0vdc
D 6.1vdc
G 3.4vdc

Q49 RX
S 0vdc
D 6.3vdc
G 0vdc
TX
S 0vdc
D 6.0vdc
G 4.8vdc

 

[nomadradio]

If you can hear it in a nearby radio on the same channel you probably have a power-stage issue.

And if you can't hear anything on a monitor radio, attach a coax jumper to it, thread the shell of the coax plug on the far end back down the coax. This makes the center pin a half-inch long "sniffing" antenna. Sniff around the transmit mixer chip and see if you can hear any signal that way. If not, the problem is upstream from the power stages.

Is sideband receive working properly? If not, this points to the carrier oscillator.

Oh, and the gate voltage on Q49 is a bit hot. Could be the driver Q49 overheated and failed. The gate-voltage trimpots should be set for proper drain current on sideband transmit with mike gain at zero.

Maybe.

73

 

[Crambone]

If you can hear it in a nearby radio on the same channel you probably have a power-stage issue.

And if you can't hear anything on a monitor radio, attach a coax jumper to it, thread the shell of the coax plug on the far end back down the coax. This makes the center pin a half-inch long "sniffing" antenna. Sniff around the transmit mixer chip and see if you can hear any signal that way. If not, the problem is upstream from the power stages.

Is sideband receive working properly? If not, this points to the carrier oscillator.

Oh, and the gate voltage on Q49 is a bit hot. Could be the driver Q49 overheated and failed. The gate-voltage trimpots should be set for proper drain current on sideband transmit with mike gain at zero.

Maybe.

73

Thanks Nomad,

If you can hear it in a nearby radio on the same channel you probably have a power-stage issue.

And if you can't hear anything on a monitor radio, attach a coax jumper to it, thread the shell of the coax plug on the far end back down the coax. This makes the center pin a half-inch long "sniffing" antenna. Sniff around the transmit mixer chip and see if you can hear any signal that way. If not, the problem is upstream from the power stages.

Is sideband receive working properly? If not, this points to the carrier oscillator.

Oh, and the gate voltage on Q49 is a bit hot. Could be the driver Q49 overheated and failed. The gate-voltage trimpots should be set for proper drain current on sideband transmit with mike gain at zero.

Maybe.

73

Thanks Nomad, anyone by chance have a clear schematic for this radio the one on cbtricks is blurry and hard to see.
Also I looked at the Allignment procedures and was wondering if they are correct? I didn’t try to adjust anything I was more interested in the voltages and frequencies and I’m seeing a lot of differences in the PLL then what the Allignment procedures are showing.

Andrew

 

[nomadradio]

The schematic posted here looks pretty clear, but it's split into two files. Somebody ought to stitch them back together.

https://cbtricks.org/radios/rci/rci_2980wx/

What differences from the alignment directions are you seeing?

73