Hi everyone. I'm new here. Wondering if anyone can help.
I'm trying to repair a Sony Micro Hi System...sony_hcd-bx77dbi
The CD player is not spinning. Think both the sled and spindle motors are not turning. I believe this is due to the voltage supply to the CD unit coming off the main board. If you have a look at the attached pic (part of the main board) there should be 3.3V going into the pins 1 and 17 of the output ribbon which goes to the CD player. But I'm getting weird voltages from -2.6V to +1V at both. There is a little cluster of transistors (the 3.3V regulator circuit) - Q302 Q303, Q392, Q361 and the voltages are mostly wrong (in the pic the numbers in Red are Sony's correct readings, the numbers in green are mine).
I thought it might be something to do with the zener diode (D304) so I swapped in a new one but still getting the same readings so could it be one or more of the 4 transistors - if so which one??? Q302's readings seem more or less correct but Q303's are just weird with the negative value on the collector. Any suggestions gratefully received...
Cheers
Tom
I'm trying to repair a Sony Micro Hi System...sony_hcd-bx77dbi
The CD player is not spinning. Think both the sled and spindle motors are not turning. I believe this is due to the voltage supply to the CD unit coming off the main board. If you have a look at the attached pic (part of the main board) there should be 3.3V going into the pins 1 and 17 of the output ribbon which goes to the CD player. But I'm getting weird voltages from -2.6V to +1V at both. There is a little cluster of transistors (the 3.3V regulator circuit) - Q302 Q303, Q392, Q361 and the voltages are mostly wrong (in the pic the numbers in Red are Sony's correct readings, the numbers in green are mine).
I thought it might be something to do with the zener diode (D304) so I swapped in a new one but still getting the same readings so could it be one or more of the 4 transistors - if so which one??? Q302's readings seem more or less correct but Q303's are just weird with the negative value on the collector. Any suggestions gratefully received...
Cheers
Tom