Hi. I'm looking for assistance with the proper bias setting for my B&K Sonata video 5 amp. From what I come up with, it should be 250 mA, measured across the negative voltage rail fuse. The five channels are at around 60mA now and I'm hesitant to raise it. It has two pairs of Toshiba 2SK405/2SJ115 output transistors per channel. One of the channels is also going dead after warming up for ten minutes or so. Any help would be greatly appreciated. Thanks.
Here's a photo. The DC offset pots are on the bottom near the fuses. The bias pots are closer to the heat sinks.
That's what I used to come up with the 250mA. 🙂 I'm hesitant to raise them from ~60mA. Any idea of the proper output transistor temperature? I suppose I could turn them up and watch the heat?