• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Cobra 29 resistors to channel display

2FB327

Active Member
Oct 31, 2012
270
54
38
Cobra 29, 2011, made in Vietnam, beige board.
Does anyone know the location for the resistors to control the brightness for the meter and channels selector.
I found some info on the 29 black and chrome model which uses a total of four.
But on this board none of the resistors are marked on the board and placement of items are different than any other 29 board I have seen.
As always thanks in advance.
 

No Rob, just a 29ltd. I picked it up for cheap and when I opened it up I noticed that R118 and R119 where not there.
IC 1 Has the cobra logo with on other markings
IC 4 is two rows of 3 pins, instead of 10 next to each other.
TR 23 is called Q23 and turned horizontal versus vertical.
L11 is gone.
 
Never worked on too many AM radios; but the solution should be the same. TR22 or Q22 (whatever it is) is the voltage feed to the ch LED display. If there is a jumper wire on the board for that path, then use that for the resistor or even a VR. You could interrupt its path with a ~10kohm VR and adjust the level to your liking.

Or find the resistance of that VR and put a fixed value on a DPST switch. Might even put a white LED in your meter and feed it power from the same switch. That will give you bright/dim for both. Or simply use a fixed resistor and be done with it.

Unless there is a better solution . . .
 

Attachments

  • adj bright.PNG
    adj bright.PNG
    55.2 KB · Views: 13
Last edited:
Thanks again Rob, I'll give a go tomorrow. I even noticed that the dull ugly wheat bulb came right from the board into the RF meter, so with my DVM I wired and LED to the bright dim center position and got it to work on bright/dim.
Now I'll get the brightness of the channel selector and it will be a go.
 

dxChat
Help Users
  • No one is chatting at the moment.