Hello all,
Happy new Year! I wish you all health, prosperity and many happy moments!
I am currently working on my first Luxman - LV 105.
I have a strange situation: Most of the time the right channel will cause the unit to stay in protection mode. Sometimes the diode LD7310 will light up and the relay will engage. And then all is ok and the sound is great...
This right channel is acting strange - when I power up the unit the diode will light for a second and then will turn off. When I power off the unit the same diode will light for a few seconds and then turn off.
What I have done so far:
- Recapped the whole main board (w/o the main filters);
- Replaced the blown Q1301 with MJE15030G;
- Checked D1305 and R1304 - ok;
- Biased both channels. When the right channel is ok, the voltages at the FETs are ok and this allowed me to do the bias. Otherwise the voltages at Q7320 and Q7322 are ca +/- 61V. Both FETs measure ok;
- Q7314 ok;
- Resoldered the whole main board;
- Checked diodes D7306, D7380; D7308 - ok;
- Cleaned the glue from the board when replacing the 6 x100mF caps and also near Q1301;
- Resoldered the board (pins) of the two tubes;
- Cleaned the switches and pots;
- The voltages at Q8303 are a bit strange - E 2,1V; C 2,15V, B 2,7V. At the collector there should be 12V. But I do not think this will affect only the right channel...
- Recapped the AV - monitor board;
- Recapped the preamp board and resoldered it.
Has any of you guys been in a similar situation? And how did you manage to fix this problem?
Any help is appreciated. Thanks in advance!
Happy new Year! I wish you all health, prosperity and many happy moments!
I am currently working on my first Luxman - LV 105.
I have a strange situation: Most of the time the right channel will cause the unit to stay in protection mode. Sometimes the diode LD7310 will light up and the relay will engage. And then all is ok and the sound is great...
This right channel is acting strange - when I power up the unit the diode will light for a second and then will turn off. When I power off the unit the same diode will light for a few seconds and then turn off.
What I have done so far:
- Recapped the whole main board (w/o the main filters);
- Replaced the blown Q1301 with MJE15030G;
- Checked D1305 and R1304 - ok;
- Biased both channels. When the right channel is ok, the voltages at the FETs are ok and this allowed me to do the bias. Otherwise the voltages at Q7320 and Q7322 are ca +/- 61V. Both FETs measure ok;
- Q7314 ok;
- Resoldered the whole main board;
- Checked diodes D7306, D7380; D7308 - ok;
- Cleaned the glue from the board when replacing the 6 x100mF caps and also near Q1301;
- Resoldered the board (pins) of the two tubes;
- Cleaned the switches and pots;
- The voltages at Q8303 are a bit strange - E 2,1V; C 2,15V, B 2,7V. At the collector there should be 12V. But I do not think this will affect only the right channel...
- Recapped the AV - monitor board;
- Recapped the preamp board and resoldered it.
Has any of you guys been in a similar situation? And how did you manage to fix this problem?
Any help is appreciated. Thanks in advance!