Hello! I have recently repaired/restored a Luxman L-100 to the best of my very limited ability. It has been running fine for a several months of intermittent use though not sounding as good as it should IMO. Yesterday something shorted out on it. Using a DBT I determined it was something in one of the power modules.(I think)
Since I have two of these units I took a module from the spare (also in the process of being rebuilt) and put it in. It passed the DBT test. I decided to adjust the DC offset and idle current on this module because I had never done that since adding new parts. I could set the DC offset very low and went to check the idle current and it read a negative 36mA! I thought that was weird so I checked the other one that has been working and it read same!
I am very confused by this to say the least! Is my DMM bad? I checked the fuse and its OK. I am sure the readings were not like this when I finished working on it the last time. If I use the idle current adjuster it barely changes the reading at all.
This is a total mystery to me now and I'm not sure how to proceed. The unit has been working OK up until yesterday. Can there even be a negative idle current at the test point? If so how could the unit be working as it was? Is the power supply board not working properly?
Any input into this is greatly appreciated because with my limited understanding I am stumped at this point.
Mark
Since I have two of these units I took a module from the spare (also in the process of being rebuilt) and put it in. It passed the DBT test. I decided to adjust the DC offset and idle current on this module because I had never done that since adding new parts. I could set the DC offset very low and went to check the idle current and it read a negative 36mA! I thought that was weird so I checked the other one that has been working and it read same!
I am very confused by this to say the least! Is my DMM bad? I checked the fuse and its OK. I am sure the readings were not like this when I finished working on it the last time. If I use the idle current adjuster it barely changes the reading at all.
This is a total mystery to me now and I'm not sure how to proceed. The unit has been working OK up until yesterday. Can there even be a negative idle current at the test point? If so how could the unit be working as it was? Is the power supply board not working properly?
Any input into this is greatly appreciated because with my limited understanding I am stumped at this point.
Mark