yamaha cr-800 power supply board issue... FR807 burned itself off board?

[James Sybert]

i have a cr-800 with no power. i checked the switch on the back and worked it several times. no change. read a bunch of threads here and immediately went to check FR807 fusistor... and it had blown itself off the board.

when it did.. it took the metal 'rings' underneath the board with it. so now, there's nothing to solder the replacement part to.

any suggestions on what i can do? (BTW, i bought a replacement board off of ebay and it has the same issue!!!)

 

[cademan]

You might have a shorted transistor causing that resistor to burn. That burnt resistor is not the problem but rather a symptom of something else that is wrong.

 

[avionic]

This fusible is shot as well.. That large blue cap C882 with the ruffled plastic sleeve looks over heated. Probably was the reason FR807 overheated. Might want to check that diode right next to FR807 (D811 ) as well.

 

[avionic]

any suggestions on what i can do? (

Have to use some jumper wires.

 

[James Sybert]

thank you for the suggestions.. i'll pull those other guys (and hope the rings don't come with them grr) and test them.

as for jumper wires.. any solid core wire work? and i'm looking at the schematic.. how to be certain where i'm suppose to jump? 'top' connection leads to the green wire.. does the bottom connect to leads right next to it (the 3 in a row)?

 

[avionic]

as for jumper wires.

I use either clipped resistor or capacitor leads.

 

[avionic]

does the bottom connect to leads right next to it (the 3 in a row)?

Clean the board with acetone. You will be able to see better where the traces go.

 

[avionic]

Just bend the new resistor leads over and solder to the appropriate locations.

 

[avionic]

I would check and replace all the fusible resistors on this power supply board.

 

[James Sybert]

fantastic ideas! i have plenty of resistor leads.. and the leads are plenty long on the resistors (non-flammable) i ordered to replace the hw22339. off to newark to grab the appropriate capacitors and that other fusible. it's a different spec than the hw22339 than the replacements i already purchased... thank you! i'll keep the thread updated as i can.

 

[avionic]

Might as well replace all the electrolytics.

 

[avionic]

Make sure you mount the new fusible resistors approx. 1/4" off the board.

 

[James Sybert]

ty! parts coming in for a cap / fusible resistor replacements from newark tomorrow..

 

[avionic]

ty! parts coming in for a cap / fusible resistor replacements from newark tomorrow..