OK so Here I go again. Im way over my head sorta… Need to replace 4 transistors on a circuit board that fried.

Great Grandson has a RC car. Runs on a 9.6v standard battery pack. It stoped being able to steer, Started to ck it out, tore it open, and the steering mech was jammed, and the motor was very warm, and trying to cycle. Freed the stuck parts, and it still would not cycle. Pulled the cover off the main board, pulled the main board, and there on the main board was 4 burnt and fried transistors. Easy access, easy de-soderable and such.

Got a magnifier out and read the # on the transistors… two were SS8550 w/ x331( couldn’t read it all) on second line, and two were 0 8050 w/ D 9H on second line.

Went up to Mouser, put in the 8550 code and there are about 10 diff listings, and the same for the 8050 ones. I’m guessing that the diff is power ratings and such.

https://www.mouser.com/_/?keyword=SS8050&gclid=CjwKCAiA2O39BRBjEiwApB2Iktrn7r7NxHXhVp4NRy0lBssdiTYdkG5f_9DgoMVGSwXPp2pY5R5osxoCcnAQAvD_BwE

And that is where I’m at… confused on which ones will or won’t work… Advice please…

Dave T

Do you have pics of the fried transistors? A lot of the differences on that mouser page are packaging. Some are voltage but the amperage specs seem consistent. All are the same kind of transistor (bipolar NPN). There seem to be 2 voltage specs, 25V and 40V. Seems unlikely you need a 40V transistor in a 9+V powered car.

This any help?

SS8550 and S8050 are the part numbers for the transistors rated at 1.5A.

Looking at Mouser site they are available

Going on the part numbers these should do the job.

SS8550 SS8550DTA ON Semiconductor / Fairchild | Mouser

SS8050 SS8050DBU ON Semiconductor / Fairchild | Mouser

The main issue may be the burnt board but it should be repairable if the tracks are still evident just replace them with solderwick and securing with an epoxy glue (araldite)

Dave Taylor said:

…

And that is where I’m at… confused on which ones will or won’t work… Advice please…

Where’s Kevin when you need him ? ! ?

https://www.alldatasheet.com/view.jsp?Searchword=SS8550

Got the transistors in … They are the correct ( read that as same Numbers) as the burnt ones… The head size is a bit smaller than those on the board… Are they OK to replace?

Thanks

Dave T.

Should be. Be sure you get the three leads in the correct order!

Dave Taylor said:

Got the transistors in … They are the correct ( read that as same Numbers) as the burnt ones… The head size is a bit smaller than those on the board… Are they OK to replace?

Thanks

Dave T.

Package sizes vary between different manufacturers the package is really only so that we can pick them up with our fingers, as long as the part number is correct you should be fine.

As mentioned previously the orientation is really the most important thing.