Kr-5150

Hello all,

I was replacing the stereo bulb on my KR-5150 when my daughter pushed the power button on. I dropped the wire and was soldering and it contacted the main amp board. Naturally the 2 amp fuse blew. To make a bad situation worse, I replaced it with a 4 amp fuse and smoked the R91 and R93 resistors on the main amp board. What should my next move be? I would really like to save this receiver.

Thanks,

CO

Well....:scratch2:......my suggestion would be to first replace any and all burnt resistors with the exact values and lets hope that nothing else was fried, burnt or shorted out? :sigh:
Next replace all fuses with "exactly" what, either the Owners Manual says or what is printed on the rear of the receiver, to replace them with.
Keep this phrase in mind...."Over voltage, under current". Meaning replace a fuse with either a 2 amp fuse or lower (such as 1.5 amp or 1 amp) with a voltage rating of 250 volts (doesn't matter if the unit says 125 volts) over voltage just indicates better protection. So in this case a fuse rated at: 2 amps/250 volts.
Once you've done this say a prayer, plug-in the receiver then turn it on and hopefully you'll have your receiver working again? If not?..:tears:...well then your going to either have to trouble shoot and locate the problem or get another receiver? :sigh:

Good Luck.

P.S. oh and download a Service Manual just in case?!

Smoked resistors with larger fuse after removing short from dropped wire indicates deeper trouble.

I predict repair beyond resistors.

If you replace the resistors and nothing else, use a dim bulb tester to fire it up.

q1 and q2 are shorted out by the looks of it .. plus quite possibly more damage .. test those outputs q1 q2 in the left channel first before doing anything else .

And unplug your gear before you start doing wiring repairs.

And don't solder in shorts !

resistor

Thanks to everyone that responded with help and advice. I was able to get a lot better understanding from the schematic and the help given.

What would be the best replacement for the two 0.47 ohm resistors that burned. Would one type be better than another. The burned resistor has 2 PSK, 0.47, and a triangle with 31 written on it.


Thanks.

Looks to be about a 2W.

Digikey stock shows some 4W (which is fine, if you have room).
http://www.digikey.com/product-detail/en/1-1623819-2/A105650-ND/2054677

I looked there since they have cheap first class mail rates. ($3 or so) BUT they do ship these in a lot of bubble wrap and a bigger box than you'd expect so I don't know if they get good postage on it.

Mouser shows a LOT more 0.47 resistors. 2W, 3W, 5W.
http://www.mouser.com/ProductDetail/Xicon/262-047-RC/?qs=sGAEpiMZZMtlubZbdhIBIFkjVTdEn2nw7FiMAeO5pEg%3d
http://www.mouser.com/ProductDetail/TE-Connectivity-CGS/ER74R47KT/?qs=sGAEpiMZZMtlubZbdhIBIBiJIqAHDdPF171DqMz%2fPDs%3d
http://www.mouser.com/ProductDetail/Vishay-Draloric/AC03000004707JAC00/?qs=sGAEpiMZZMtlubZbdhIBIBpEgVvVFfjkwWNI4DU7AcM%3d
etc....
http://www.mouser.com/Passive-Components/Resistors/_/N-5g9n?P=1z0x70aZ1z0wo8tZ1z0wszxZ1z0wui7
But their cheapest postage is about $7.

Those are the emitter resistors? Re100, Re99, Re91, Re92?
IF those toasted, you better pull the output transistors and test them. I'm betting you blew an output!