Recently recapped my dh-220. on the left channel was able to set the bias current to 275ma and dc offset to 0V with no problems.
However, on the right channel, I cnat get more the 60ma on the bias. I check P2 and it seems fine. Resistance goes up to 1K.
So I started checking the other resistors in that network. R22 and R23 both measure to spec. R38 isn't the 28K resistor called for in the parts list, but is 17.4k. This is the same in both channels, however in the right channel, it measures at 17.1K (on the left it measured to spec).
So, I'm thinking I should replace that resistor. 300 ohms is almost 30% of the range of P2.
But, I thought I'd check in here first to see what the resident Hafler experts thought ;-)
Note all measurements where done with components in the board.
Thanks,
James
However, on the right channel, I cnat get more the 60ma on the bias. I check P2 and it seems fine. Resistance goes up to 1K.
So I started checking the other resistors in that network. R22 and R23 both measure to spec. R38 isn't the 28K resistor called for in the parts list, but is 17.4k. This is the same in both channels, however in the right channel, it measures at 17.1K (on the left it measured to spec).
So, I'm thinking I should replace that resistor. 300 ohms is almost 30% of the range of P2.
But, I thought I'd check in here first to see what the resident Hafler experts thought ;-)
Note all measurements where done with components in the board.
Thanks,
James
