Panasonic RF4800 SW. Ooops! Help!

[cdnpont]

All good advice appreciated!
I tried a little mocking up with the LM chip on a breadboard with a 9v bat... with no luck. It's hard to get onto the board with the cut off pins in place.
So I just mocked up the radio and stole my daughters Bose BT speaker. works more than fine off the rec out, all bands functioning normally. I'll listen to it in this state until I get the NOS chip. Cheers.

 

[audioguru]

I saw that very expensive and tiny Bose amplifier speaker being demo'd at Costco. It sounds fantastic for its small size and is much better than my son's cheap Chinese copy.

 

[dr pepper]

Temporary solution sorted!

Did you try the Lm386 on the record o/p, it should work also, do you get no sound from the '386 at all?, not even a buzz, if so maybe the speaker is blown open circuit too, quite possible under the circumstances.

 

[cdnpont]

Kind of fun having a open chassis....

 

[dr pepper]

There is a lot of knowledge on this here forum, and most share it, its a good place to get into electronics.

 

[cdnpont]

Well, I received my replacement chip yesterday from eBay seller wehavethatitem in NJ. Got two for $21 quickly delivered to Canada.

Used a lower watt iron to heat and push out the old pins that had been snipped off. Pretty much fell right out. The heatsink portion came off easy as well.
I then used a 3mm soldering wick to remove any excess solder (worked great). Made sure the holes were clear. Used a paper towel and the iron to sop up some wax (securing a small cap on the chip). Cleaned the area with solvent. Fitted the new chip, bent two pins to secure, then quickly and easily soldered it in. All done under a led lighted magnifying glass/holder (made it so much easier).

Hooked the board back up....and it actually worked! It's alive! Volume, bass and treble all work normally. I call myself lucky I didn't damage much more.

So success on my first chip R&R!

I really believe all this happened for me to learn, but lesson learned was don't assume the inner portion of the power plug is positive, and maybe have a look at the label at the plug lol! Good to know places still have nos components for older radios. And I now have the confidence to replace the electrolytic caps when ready.

Thanks for all your help on this issue guys. I really appreciate it! Great site, great people.

Cheers, Mark

 

[JimB]

It is good to hear a success story, thank you for the feedback.

JimB

 

[dr pepper]

A lot of repairs are not much more difficult.
Your now a radio tech.