Yamaha CR-640 Component Identification

[potch]

Hello, picked this unit up today and pulled the cover off to have a look. There are 2 square tubes protruding up from the board. One is loose and the 2nd one is not. They both seem to have corrosion around them. The loose one is circled in red in the attached picture. What is the function of these components, is the corrosion an issue and is the loose one also an issue?

The receiver seems to work with the exception of the bulbs. Oddly enough, when I was trying the FM tuner, the bluetooth receiver, connected to the AUX port and streaming from my iphone, was bleeding the music over to the FM channel.

 

[avionic]

What is the function of these components,

They are heatsinks for TO-220 transistors. Usually power supply " pass " transistors.

 

[potch]

They are heatsinks for TO-220 transistors. Usually power supply " pass " transistors.

Any issues with the loose one or what looks to be corrosion or some type of build up?

 

[mbz]

Any issues with the loose one or what looks to be corrosion or some type of build up?
Check how the heat sink is secured, sometime the have a twisted lug, or soldered or glue alone as it appears in this case. I'd clean up/remove the glue, it may damage surrounding parts then reapply a non-conductive/corrosive glue of your choosing. More importantly check the solder joints for the transistor, google dry solder joints for pix.

 

[avionic]

Any issues with the loose one or what looks to be corrosion or some type of build up?

Look at the solder connections for circular cracks around component lead. Its loose because the dried up glue is no longer glue. I would suggest unsoldering the components and remove all the dried glue and corrosion. Then use a little RTV and remount and resolder to the board. Wouldn't hurt to put some fresh heatsink compound between the transistor and the heatsink as well.

 

[avionic]

I use Permatex " Ultra Black" gasket maker . Its non-corrosive and very low out-gassing sensor safe. for all my electronic adhesive duty.

Amazon.com

 

[avionic]

would suggest unsoldering the components and remove all the dried glue and corrosion.

That goes for any other of the dried up and crusty SONY Bond glue in the rest of the receiver.. The old glue is now a corrosion enabler.And will corrode anything metallic it is in contact with.