phase linear 400
- Thread starter gene french
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- Halfbiass...Electron Herder and Backass Woof
if you are missing your bias reading, it has zero to do with open emitter and base resistors, those should be fixed but are not the cause of zero bias.
If you are convinced that your bias transistor is good, then the next step is to check out the other resistors (fuses) in the circuit. R37L (22), R41L (22), R38L (1), R21L (56), R32L (56)
Seems like you took out all the fuse resistors on the backplane so now you have to check the fuse resistors on the control board.
If you are convinced that your bias transistor is good, then the next step is to check out the other resistors (fuses) in the circuit. R37L (22), R41L (22), R38L (1), R21L (56), R32L (56)
Seems like you took out all the fuse resistors on the backplane so now you have to check the fuse resistors on the control board.
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- music...the healer of souls...
i checked every component on the left back plane...comparing it to the right...when questionable, i removed one leg...and confirmed...
the bias is constant at 14mv...adjustment doesnt affect much...see the photo a page or two ago...you can see ...
right channel bias set as per documentation...
all i checked on control board was +- 15v...
the components you listed are on backplane or control???
i will refer back to docs to get my bearings...
thank you...
the bias is constant at 14mv...adjustment doesnt affect much...see the photo a page or two ago...you can see ...
right channel bias set as per documentation...
all i checked on control board was +- 15v...
the components you listed are on backplane or control???
i will refer back to docs to get my bearings...
thank you...
If you are convinced that your bias transistor is good, then the next step is to check out the other resistors (fuses) in the circuit. R37L (22), R41L (22), R38L (1), R21L (56), R32L (56)
Seems like you took out all the fuse resistors on the backplane so now you have to check the fuse resistors on the control board.
Seems like you took out all the fuse resistors on the backplane so now you have to check the fuse resistors on the control board.
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- music...the healer of souls...
i was trying to locate the bom for the control board....which i do not have in the 34 document files you sent when i purchased the wopl....
i do have the bom for the back planes....and since those resistor numbers are not on the back plane bom...
they must be on the control board....
if you could send the bom for the control board....that would be nice...
thanks
i do have the bom for the back planes....and since those resistor numbers are not on the back plane bom...
they must be on the control board....
if you could send the bom for the control board....that would be nice...
thanks
- Joined
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- music...the healer of souls...
You will get very low bias readings if you do not install the bottom row of transistors. Have you installed the bottom row?
If no, install them and recheck.
If yes, measure the voltage at the collector and emitter of the bias transistor at the control board connection points with your DVM black lead connected to the single point ground.
If no, install them and recheck.
If yes, measure the voltage at the collector and emitter of the bias transistor at the control board connection points with your DVM black lead connected to the single point ground.
As long as both 10 ohm bias resistors on the backplane and both of the 150 ohm base-emitter resistors are good, that is all you need to power up the backplanes with the bottom row transistors in. You have a schematic, you will understand by looking at this why you won't get a proper bias reading until the bottom row transistors are installed.