Radio too Hot?

[PATnKIM]

I'm using a BC250D that I bought on Ebay not too long ago. About 3 or 4 days after receiving it. It just quit "broadcasting" I sent it to Uniden and they say they replaced the PCB. It has been working fine(2 weeks) until yesterday. I take it with me during work and listen while I'm driving around. I lock it in my vehicle when I make my "stops" sometimes it's an hour or 2 at a time sitting in the closed up vehicle. Beginning yesterday about mid-day I turned it off, took care of business and when I turned it back on there was no sound except for an occasional crackle. It locks on signals and I even hear the beep for channels it is set to alert on. When I got home I set it on the counter, turned it on about an hour later and it worked fine. Took it with me again today, same thing happened again.
I would really like to hear if anyone has experienced similar problems with their radio and opinions on whether or not it is heat related. I live in Central Florida. Temperatures have been low 80's, not sure about vehicle interior temps.
Thanks
Pat
Apopka, Fl.

 

[phoenix]

that's the problem....high heat in the car. you could "take it with you"? or put it in an insulated bag with a "half frozen" ice pack ?

 

[linuxwrangler]

Could be heat-related - perhaps the speaker-coil is expanding and rubbing. I don't know if you have enough data-points.

Temperature extremes are not good - electronics that are operated at a constant cool temperature have much higher average lifespans that those operated in excessive temperatures. Rapid temperature swings are not too good either - especially when it leads to mechanical stresses due to uneven temperatures.

On the other hand, temperature extremes aren't necessarily all that bad. Your car radio, CD/tape player, mobile scanner and other onboard electronics routinely spend their entire lives in environments ranging from sub-zero Minnesota winters to blazing Arizona summers.

Storage temperature ranges are generally higher than operating temperature ranges and my 396 manual has a max operating temperature of 60C (140F) which is warmer than I prefer to be (even if I was raised in the Mojave desert). But car interior temperatures in the desert can easily exceed 140.

It would be interesting to use a headphone and see if that works when the speaker doesn't.

 

[PATnKIM]

Thanks for the responses. I was thinking heat also but now I'm beginning to wonder.
A little more info.. The first 4 or 5 days I got it back I took it with me in my work truck. Worked fine all day outside temps were the same range. No problems after being left in the vehicle. Today, when it quit working I took into my office when I got back. Tried it about 20 minutes after I got back and it worked fine. Left work for home, had A/C going in my vehicle but didn't turn it on. When my carpool partner was dropped off I turned it on...nothing, same problem. The temp range in the manual says up to 140 like previously stated. I know it didn't get to 140 walking to the car and waiting for the A/C to cool down. I now have it sitting on my desk and it seems like after 15-20 minutes some modulation is trying to come through (sounds like a badly blown speaker) In answer to Linuxwrangler, no the earphones don't "hear" anything either. It's like the entire sound circuit dies.
I'm thinking about opening it up to see if anything is "obviously" wrong. By the way, what do you mean by data points? Thanks again for y'alls help.
Pat
Apopka, Fl

 

[linuxwrangler]

By the way, what do you mean by data points?

Pieces of information. Within limits, the more the better. Sort of like the person who, based on a random sampling of one, decides that all residents of the US are Gay Hispanic Female Republicans. Addition of more data-points will render a more accurate picture.

Sort of a shorthand way of saying, "I think we need more data before we can be reasonably confident of our explanation."

 

[linuxwrangler]

Note that my earlier comments regarding temperature apply only to healthy electronics. A flaky component might start failing under conditions that are well within normal specs. This is why heating and/or cooling components is a commonly used troubleshooting technique - especially for intermittent trouble.

Humidity is another environmental consideration. If you take your cold scanner from your air-conditioned house out into the warm and humid outdoors, moisture can condense where you don't want moisture to be. That's why a lot of environmental specs for humidity ranges include the parenthetical comment"(non-condensing)". Given your descriptions, it doesn't sound like condensation is a problem.

Make sure your batteries are OK - they are temperature sensitive, too, and could be old or have a bad cell.

If your batteries are good and you are using the scanner within the specified environmental limits and it is not working, you should contact Uniden support for advice - especially since you just got it back from repair. The first diagnosis may have been wrong or there could have been a problem with the repair. I don't know what, if any, warranty Uniden has on repairs but I can assume that you would expect it to function for more than two weeks.

 

[slicerwizard]

Sounds like a bad cap or cold solder joint. Tracing the audio from the discriminator to the speaker would narrow it down.