Sidebar Sidebar
  • 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.

DX500V L1 choke smoking

144inBama

144inBama

Sr. Member
Apr 22, 2020
761
1,352
153
54
Lower Alabama
I dug around for awhile looking for an answer but can't seem to find it in a post...
As the title states, the L1 choke started smoking on the 2nd key of the new amp. I'm running a 29 LTD classic chrome at 6-8 watts, antenna is a Wilson 1000 with a VSWR of 1.1/1.2 radio to meter to antenna but with the amp inline it jumps to 1.5/1.6 with power off (meter in between radio and amp). Can someone suggest a place to start looking for a issue before I smoke the thing completely? Also, I bought it online and the conversion was done by them....I actually have zero idea what I'm looking at to see if it was done right or if something is missing.
Thanks in advance
144
 

For starters, your carrier is set way too high! Around 2 watts and let it swing from there into the box. The meter after the amp if it's rated for the wattage of the amplifier.
 
OK, check again.... Meter between radio and amp is 3+ VSWR.... Meter after amp VSWR is 1.4 but that is with the amp off. If I press the preamp button, with the meter between the radio and amp, the VSWR go over 6, meter after the amp 1.3. All of the readings are with the amp off/power disconnected. I've been digging through the old post but haven't really seen anything that fits my issue completely.
 
Kind of like an input or pass through tune issue but I'm no amplifier guru here. Maybe Mr Shockwave will jump in here, he's really knowledgeable in that department. Sorry I'm not much help. I still think 4 watts carrier is too high, really needs to be around 2 watts for that Texas star.
 
Eldorado828 said:
I still think 4 watts carrier is too high, really needs to be around 2 watts for that Texas star.
Click to expand...
I'm trying to get up with a guy to put a variable in it. Just aren't as many radio techs around here like there used to be. I've been away from the hobby for about16 years, so I'm nowhere near as up-to-date on this stuff as I used to be.
 
L1 is the only thing I can see that looks like it took some damage. If no one can give me a definite answer, I'll wait until I get the variable installed and try it again... Which isn't a bad idea regardless. I appreciate your input Eldorado828, now I have a little something to work with. I'm trying to learn the operation of the amp as well as what is/caused the problem here.
Again, thanks.
 

Attachments

  • 20200503_144656.jpg
    20200503_144656.jpg
    1.4 MB · Views: 34
This may be something as simple as...

Did you resolder any work on the board?

Like Tighten any loose hardware or "bounce" the amp?

Take off the top panels - and look thru the side to see if that Choke is hitting against or welded onto the heat sink.- if not at least look around that area for potential blobbing solder or debris that can short that part of the board that uses L1.

L1 is the "choke" for powering the "lights" so unless there may be a bigger issue further up the chain with the lamps like they shorted out - review the CB Tricks sites' wiring of this to be sure.

upload_2020-5-3_17-43-58.png

From what I can tell by your board - you have power thru the relay to the "key" lamp that lights your meter...

IT is supposed to keep RF off the line when you have the Pre-amp on to allow it to send Signal From 8-9 Thru S2 then back thru to Relay 5-6 then to Radio even in Bypass - so the SWR to shoot up means something in the Relays path is affected - so L1 looks to be the symptom - we can only hope it is due to a simpler debris or solder blob and only L1 but not the Relay contacts 9-8 or 9-10 contacts got burned up.
 
Last edited:
  • Like
Reactions: Shadetree Mechanic and 144inBama
Handy Andy said:
This may be something as simple as...

Did you resolder any work on the board?

Like Tighten any loose hardware or "bounce" the amp?

Take off the top panels - and look thru the side to see if that Choke is hitting against or welded onto the heat sink.- if not at least look around that area for potential blobbing solder or debris that can short that part of the board that uses L1.

L1 is the "choke" for powering the "lights" so unless there may be a bigger issue further up the chain with the lamps like they shorted out - review the CB Tricks sites' wiring of this to be sure.
Click to expand...

Obviously you are 100% correct.... I found some solder splash under the power button, so I removed it, gave it a double check and hooked power to it, as soon as I pushed the power button there was a pop and all lights went out. Guessing I freaking missed a piece and moved it because the trace that runs under the switches was blown in half...neither fuses was blown. I'm starting to remember why I stepped away from this hobby...
 
  • Like
Reactions: Shadetree Mechanic
There are few out here - you can PM them too - I wish I could help but with the Covid stuff as well as final say from my wife - shes' still upset from a lot of stuff she needs to sort out, so I can't even offer - but hey, maybe it's just the relay and you can do a simple fix for that...

Remember the Pic? Just unsolder the relay and check continuity - you have everything you need already if you only had the relay...

The SWR thingy can be a burnt trace - so that is another simple fix.

The job I did have I ordered stuff for repairs thru the shop so I had that contact but not now.

A lot of this is just getting the courage and steadying the nerves down from all that happened - just relax you can get your head around this so logic and reasoning takes over and... WHAM! You're now a tech - welcome to our world - we just live in it...

Firstly - when SWR shoot up in Preamp mode? then the bypass is bad, either by trace or by relay - I'd start there - and don't rush either. Again work goes better when you're relaxed...

so...

Relax!
Insert ZEN Moment here...
866679image00115.gif
 
  • Like
Reactions: Shadetree Mechanic, Slowmover and 144inBama

dxChat
Help Users
  • No one is chatting at the moment.
  • @ Wildcat27:
    Hello I have a old school 2950 receives great on all modes and transmits great on AM but no transmit on SSB. Does anyone have any idea?
  • @ BJ radionut:
  • @ ButtFuzz:
    Good evening from Sunny Salem! What’s shaking?
  • dxBot:
    63Sprint has left the room.
  • dxBot:
    kennyjames 0151 has left the room.


      Top Bottom
      Back