Swan 500cx blew and started smoking.

[midnightpulp]

Hi all. A friend of ours passed away who was huge into CB/Ham. I picked up various items from his estate including transceivers, mics, etc. One of the coolest units is a Vintage Swan 500cx transceiver with an external 117xc power supply. Unfortunately, when I plugged everything in and flipped the switch, there was a pop from the 500cx, followed by smoke. I know nothing about these units so I'm wondering if anybody out there might have an idea what went wrong and how to repair it. I have repaired the two arcade machines I have so I know how to solder, use a multimeter, etc.

It's also worth noting that I likely contributed to the situation by using a power cord that wasn't the 117xc's. It had the same 15 pin connection, but was used with an old International transceiver. I figured since it had the same pin connection, there would be no problem. However, hours later I found the actual cord meant for the 117xc, which has a built in fuse.

Any help is greatly appreciated.

 

[W5LZ]

I'm familiar with the Swan 500, and there's no easy, definite, answer to your question. There are just too many possibilities, but the first being that power cord.
The only suggestion I'd make is to take the covers off, -AFTER UNPLUGGING THE POWER SUPPLY!-, and see what appears to be 'burnt' up. If you're not familiar with trouble-shooting electronics I think you might find someone who is, there's enough high voltage in that thing to really ruin your day/month/insurance company!
- 'Doc

 

[Beetle]

I'm assuming you don't have a manual for that grand old rig, so: http://bama.edebris.com/manuals/swan/500cx/ .

As a rule, NEVER fire up a piece of gear before you've gotten the manual and become somewhat familiar with it.

 

[midnightpulp]

Thanks for the help, gentlemen. Appreciate it. I'll probably put it up on eBay and let someone well versed in vintage electronics repair it.

 

[midnightpulp]

Took the covers off the rig and checked it out. Looks good, actually. I don't see any signs of burn except at the top of the RCA 6ck6 tube that is located where the unit smoked. But isn't discoloration of that sort normal for a tube? Also, the 3 transistors at the rear of the unit all zeroed out when I checked them with a analog MM. The unit was powered down of course.

Here's some pics:

 

[AudioShockwav]

Pull the "bottom cover" and look for any toasted parts...smell for the magic smoke......
Pull the plugs covers and see if they are wired the same, you may have a failure from age, or from the cord.
It could be that one or more of the old caps in the bottom of the rig have gone dry/leaking/shorted.

73
Jeff

 

[midnightpulp]

Pull the "bottom cover" and look for any toasted parts...smell for the magic smoke......
Pull the plugs covers and see if they are wired the same, you may have a failure from age, or from the cord.
It could be that one or more of the old caps in the bottom of the rig have gone dry/leaking/shorted.

73
Jeff

Will do. Thanks.

 

[unit248]

BTW, the silvery discoloration on the inside of tubes is normal. Vacuum tubes need to be completely free of oxygen and other non-inert gases, but it's difficult to pump out all the air during manufacturing, so they build tubes with a small amount of reactive material inside called a 'getter.' (Getter - Wikipedia, the free encyclopedia) Once the tube is assembled and sealed, the getter is heated which causes it to bind to any stray gas molecules, and the result is a metallic oxide residue on the inside of the glass envelope of the tube. (Think of an old school camera flash bulb going off.)

-Bill

 

[Rigormortor]

Open up the radio and start tracing it from the power connector, could be anything, blown resistors, open wires, blown electrolytic caps.... usually you can find alot by looking, you will see what is burnt or blown. Start measuring with an ohm meter and cap meter and start replacing bad components.... this is how I brought an HW-101 back to life. Good luck.