RuffzGuts
Super Member
Hey Yamafolk!...I've a little CR-450 receiver here that is driving me nuts...
I was hoping maybe someone could possibly shine a light on something I am overlooking.
The amplifier was given to me with a blown fuse...this amp runs 4x 3A glass fuses...the blown fuse is closest to side of unit.
I replaced fuse and plugged into Dim Bulb, it flashed up straight away so I turned the unit off and began troubleshooting....
I have been over every transistor in the amp now....checked as much as I could without de soldering including all caps while I was there..
I could not find a fault...so started checking all wires...nothing....then after switching on and off on and off through testing, suddenly it came good...
puzzled I thought ok...I shall leave it open and listen to it for a few days...adjusted bias, dc off set all good...sounded wonderful, first Yamaha amp I've had and I like....definitely has its own signature sound...
So, performed fine via dim bulb for a few days, I closed it back up...
I then decided to open back up to change a bulb out......turned her on again, bang short came back....disconnected new bulb back on dim bulb,,,flashed up...
at this point I went away to bang head against wall....
Came back went over it couldn't find anything...noticed some suspect (cracked)solder joints so I touched them up, all around power supply circuit...
switched on.....all good, No short....Hmmmm
went away few a few hours, plugged in again....and dim bulb flashes up!
I think its haunted...
any ideas?
I was hoping maybe someone could possibly shine a light on something I am overlooking.
The amplifier was given to me with a blown fuse...this amp runs 4x 3A glass fuses...the blown fuse is closest to side of unit.
I replaced fuse and plugged into Dim Bulb, it flashed up straight away so I turned the unit off and began troubleshooting....
I have been over every transistor in the amp now....checked as much as I could without de soldering including all caps while I was there..
I could not find a fault...so started checking all wires...nothing....then after switching on and off on and off through testing, suddenly it came good...
puzzled I thought ok...I shall leave it open and listen to it for a few days...adjusted bias, dc off set all good...sounded wonderful, first Yamaha amp I've had and I like....definitely has its own signature sound...
So, performed fine via dim bulb for a few days, I closed it back up...
I then decided to open back up to change a bulb out......turned her on again, bang short came back....disconnected new bulb back on dim bulb,,,flashed up...
at this point I went away to bang head against wall....
Came back went over it couldn't find anything...noticed some suspect (cracked)solder joints so I touched them up, all around power supply circuit...
switched on.....all good, No short....Hmmmm
went away few a few hours, plugged in again....and dim bulb flashes up!
I think its haunted...
any ideas?
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