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View Full Version : Need an electronics opinion (for any master electronic technicians)



KØWVM
10-27-2015, 10:42 AM
Hey folks,

My FT-8500 blew a capacitor and it was running up until a few years ago and I took a hiatus from ham radio briefly when I moved to Germany. I get back, reinstall the radio into my Honda van and within a couple of days, there was a whiff noise coming through the external speaker and then I could smell that all too familiar burning electronics smell. It was not running and I actually had the display off the remote faceplate. I opened up the radio and there appears to be a fairly good sized dried pool of a silver-ish substance near the capacitor on the circuit board. It won't turn on now and so my guess is that since the radio is 20 years old that that is the problem and will be getting it repaired.

Now to why I am writing...

I have a IC-706MkIIG that I am running right now in RX mode, no TX and off a fellow ham friend's recommendation that I let it run without doing anything else for now. This also includes the Astron power supply I used to run the radio.

Since the radio and power supply were also off for the same timeframe, is there such thing as a "re-burning in" of electronic parts such as a capacitor within them that hasn't seen any activity for 3.5 years, up until now? Do I need to let them run 24/7 for a specific period of time to "massage" the parts within to get back into operational shape before I start making contacts again?

I don't want to ruin a radio that is about 10 years old and a power supply that is about 5, but I also don't want to run them 24/7 either as my friend recommended. As of this morning before I left for work (around 4:30am local), I went and sniffed around parts of the equipment and I don't smell the same odor as what came from my FT-8500. They have been running for about 16 hours now...

Thoughts...

N8YX
10-27-2015, 10:55 AM
Certain wet-electrolytic capacitors of yore may be "rejuvenated" by operating the equipment in a lightly loaded fashion for a bit, but it's been my experience that when the paste dries out the only sure-fire fix is to replace the part.

About your FT-8500:

Get a service manual and tell us where the component sits in the circuit.

Is the PCB area where the cap is mounted damaged as a result of the liberated electrolyte? If not severe, the board itself might be repaired - along with the rest of the radio.

FWIW, I've had gear which has remained in a powered-off/stored state for years and never had a failure with electrolytics unless they were on their way out to begin with. Tantalums, on the other hand... :rant:

KØWVM
10-27-2015, 12:22 PM
Certain wet-electrolytic capacitors of yore may be "rejuvenated" by operating the equipment in a lightly loaded fashion for a bit, but it's been my experience that when the paste dries out the only sure-fire fix is to replace the part.

About your FT-8500:

Get a service manual and tell us where the component sits in the circuit.

Is the PCB area where the cap is mounted damaged as a result of the liberated electrolyte? If not severe, the board itself might be repaired - along with the rest of the radio.

FWIW, I've had gear which has remained in a powered-off/stored state for years and never had a failure with electrolytics unless they were on their way out to begin with. Tantalums, on the other hand... :rant:

Got a call from my friend... He researched the FT-8500 model and from his understanding those radios were the last batch of radios that had the capacitors made in the late 80's/early 90's that were of poor quality. He was amazed mine lasted this long... Another friend in Iowa might be offering to repair the radio for me since I do not have the equipment or resources to do such a repair at the moment.

As far as the 706... I might have better luck as long as I take an easy on her. LOL!

N8YX
10-27-2015, 12:41 PM
Got a call from my friend... He researched the FT-8500 model and from his understanding those radios were the last batch of radios that had the capacitors made in the late 80's/early 90's that were of poor quality.
That's what you get when cost drives the day, not quality.

The whole "bad caps" bit has its roots deep in industrial espionage and outright theft.

Word to any budding component start-ups:

If your chemists are going to steal the formula for electrolyte paste from their previous (established) employer, make sure they steal the whole damned formula without omitting the bit which minimizes hydrogen outgassing. An excess of that in a component does tend to make them go boom.

KJ3N
10-27-2015, 02:30 PM
Word to any budding component start-ups:

If your chemists are going to steal the formula for electrolyte paste from their previous (established) employer, make sure they steal the whole damned formula without omitting the bit which minimizes hydrogen outgassing. An excess of that in a component does tend to make them go boom.

http://i.imgur.com/EHwr4jg.gif

N8YX
10-27-2015, 02:34 PM
http://i.imgur.com/EHwr4jg.gif

I fired up a powered-off PC with Lilon (bad) caps aboard one time. Wasn't just a big bada boom - sounded like a 44 Mag going off in my lab! :shock:

W2NAP
10-27-2015, 03:42 PM
I fired up a powered-off PC with Lilon (bad) caps aboard one time. Wasn't just a big bada boom - sounded like a 44 Mag going off in my lab! :shock:

yep they sure go out with a bang

kb2vxa
10-28-2015, 12:10 AM
As far as the Icom goes (and I own one too) it should be "burned in" by now, if it didn't fall down and go boom as mum used to say by now it probably won't. Now take the covers off and clean out any dust, don't forget the air intake filter on top. Then for the acid test, run the transmitter into a dummy load and see if the magic smoke stays inside. It's normal for the fan to run all the time and kick into high gear on transmit staying there until it cools down. It's also normal for the case to get rather hot, some think abnormally hot.

I'll leave the FT and stolen electrolyte formula goo to the masters, my PhD expired with tubes. I'll certainly agree on one thing, when 'lytics go boom they go BOOM and boiling goo and steaming 'lumium on my face sure didn't feel very nice.