• 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.
  • Click here to find out how to win free radios from Retevis!

Ranger RCI-69 (1st edition) blowing finals...

Hawkeye351

Well-Known Member
Jun 27, 2021
569
477
73
57
Got a Ranger RCI-69 (1st edition) on the desk today.

Reason for being on my desk:
Blowing finals not long after being replaced.

Evaluation:
The last final (RT1) shorted and next to last final (RT1) weakened, then popped.

I've replaced these mosfets once before about 2 months ago, then the user stated he had an issue with the input of his amp and it took out those new finals. I just replaced those mosfets again, keyed up for a brief second and pow, it blew the last final in the chain again. Each time I replace finals, I always reset the bias before testing it, as I did this time also. The bias sets great, but once you reattach the bias jumpers and key up, pow it blows a final, as if it sees an immediate high SWR, but my external meter shows a perfect SWR from my dummy load. When it blows a final, the radio immediately shuts off and the power supply won't come back on unless you unhook the DC supply feeding the main board.

Any advice guys/gals?
 
  • Wow
Reactions: doffo

Dummy loads are non-reactive, so harmonics and other spurious emissions are all the same to the dummy load. It will absorb all of it without any reflection. To see no reflection (flat SWR) on a dummy load is expected.

Try the next batch of finals into a dummy load only (so there are no reflections to do damage) and have a look at the spectrum coming out. Any RF not on 27MHz will be bouncing back to the finals when the radio is connected to anything other than a dummy load. Maybe the harmonic trap is messed up or higher gain replacement parts are causing oscillations.

Edit: Should have asked first. Is it blowing on the dummy load too? Or just into a reactive load?
 
  • Like
Reactions: Eldorado828
Check for continuity between the antenna jack and ground just to be sure none of the filter and matching caps shorted.
 
  • Like
Reactions: Hawkeye351
I don't have a schematic, using the dx55hp as a reference since it is dual final using 520's.

Another thing to check would be the zener diodes. They don't do much for biasing, they just protect the gate from higher voltage spikes. If somehow the driver or self-oscillation provides more than 20v to the gate, its toast (and I don't think it would even take that much since that datasheet spec is just for ESD or oops moments, not repeated spikes that turn it on hard over and over).
 
  • Like
Reactions: Hawkeye351
Got a Ranger RCI-69 (1st edition) on the desk today.

Reason for being on my desk:
Blowing finals not long after being replaced.

Evaluation:
The last final (RT1) shorted and next to last final (RT1) weakened, then popped.

I've replaced these mosfets once before about 2 months ago, then the user stated he had an issue with the input of his amp and it took out those new finals. I just replaced those mosfets again, keyed up for a brief second and pow, it blew the last final in the chain again. Each time I replace finals, I always reset the bias before testing it, as I did this time also. The bias sets great, but once you reattach the bias jumpers and key up, pow it blows a final, as if it sees an immediate high SWR, but my external meter shows a perfect SWR from my dummy load. When it blows a final, the radio immediately shuts off and the power supply won't come back on unless you unhook the DC supply feeding the main board.

Any advice guys/gals?
This is a photo of a bent board on a new out-of-the box Ranger made mobile radio. Should the radio be turned-on and used?
 

Attachments

  • Bent Board.jpeg
    Bent Board.jpeg
    229.2 KB · Views: 17
This is a photo of a bent board on a new out-of-the box Ranger made mobile radio. Should the radio be turned-on and used?
Wow, how did they even get the screws in? Quality is in the dumpster, and it's a shame to see them going down hill. I really wish they could have Anytone build them a few radios....
 
  • Like
Reactions: Hawkeye351
Can the holes be reamed out a little? Maybe a dremel using a carbide cutter? I've done that while Frankensteining two radios together.
carbide.jpg
 
  • Like
Reactions: Hawkeye351
Can the holes be reamed out a little? Maybe a dremel using a carbide cutter? I've done that while Frankensteining two radios together.
View attachment 70820
Yes, it is possible, but I don't have the radio. I am assuming this is not the first and only radio produced and released with a bent board because the hole was probably punched / drilled by an assembly line machine. The assembly line must continue to move, and installer of the board had no choice but to bend the circuit board to attach the tab. Is this another normal and acceptable practice? What is the longevity of a radio with a bent / distorted circuit board? It's just another example of Form, Fit and Function.
 
  • Like
Reactions: Hawkeye351

dxChat
Help Users
  • No one is chatting at the moment.
  • @ Joseph23:
    Happy Thanksgiving to all and a very merry Christmas and a happy Newyear also. !!!!!!!!!!!!!
  • @ Moleculo:
    Congrats to GlocknSpiel for winning the Black Friday Radioddity QT60 Pro giveaway contest!
  • @ Deon:
    Good day, I have an Icom IC910H radio. I want to program a memory with split frequency tone on TX only and NO tone on RX,. Is this possible to do from the face of the radio? I don't have the interface to connect to a computer.
  • @ crappykraco:
    @Deon very unlikely to get a response here. You are better off starting a thread on the topic.
  • dxBot:
    Backwoods40 has left the room.