I removed the resistor R363 it did not drop the voltage, I went ahead and replace Q305 and Q306 for good measure now the voltage is even higher at -2.123vdc.
I dont know whats up with this amp. The voltage is also on the drains of Q310 and Q311 could those output fets be leaky or do you think I have a resistor out of tolerance somewhere???
This amp is becoming very frustrating for me glad its mine and not a customers.
Thoughts??
I dont know whats up with this amp. The voltage is also on the drains of Q310 and Q311 could those output fets be leaky or do you think I have a resistor out of tolerance somewhere???
This amp is becoming very frustrating for me glad its mine and not a customers.
Thoughts??
I removed Q310 and Q311 from the circuit to do some testing.
That removes the voltage from the bridging terminal, and there is no voltage on the drain pads on the board where Q310 and Q311 are soldered.
The gate and source of Q310 has -33.45vdc......however the source of Q311 has +33.45vdc but the gate has only 18.25vdc.
What do you think on that?
That removes the voltage from the bridging terminal, and there is no voltage on the drain pads on the board where Q310 and Q311 are soldered.
The gate and source of Q310 has -33.45vdc......however the source of Q311 has +33.45vdc but the gate has only 18.25vdc.
What do you think on that?
HAving that much difference in voltage between the gate and source should have made the amp draw excessive current.
Did you check the outputs for leakage from the gate to source (out pf the board)? If these are the BUZ transistors, they tend to leak/short gate to source. This generally causes the output to be distorted.
Did you check the outputs for leakage from the gate to source (out pf the board)? If these are the BUZ transistors, they tend to leak/short gate to source. This generally causes the output to be distorted.
This amp has IRF540 and IRF9540 outputs. The voltage measurements I gave were aquired testing the pads on the board with the output fets removed. Just wondering why the gate pad of Q311 would only have 18.25 volts dc.
I think there must be two different 550X amplifiers. The schematic diagram that I have (including board layout) has the file name 550X but is marked 600a4. There is no PC# on the schematic diagram. The diagram that I have shows 4 FETs/channel.
Post a photo of your board if it's different (or send me the diagram for your board).
babin_perry@yahoo.com
From Post #36, why didn't you ask about Q318 and Q323 if they're not in your amp?
Post a photo of your board if it's different (or send me the diagram for your board).
babin_perry@yahoo.com
From Post #36, why didn't you ask about Q318 and Q323 if they're not in your amp?
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