Long story short.
The amplifier powers up normally but the relay doesn't engage, the pin for it at the PS board is tied to q2, q3, q4. These have been swapped before me, all being npn which is odd, doesn't seem right. At least one should be pnp to pull to ground !? It's not the the relay itself, it works, tried it outside of the board. There is a 1n4148 diode between the relay and the PS board, changing this one did not do anything.
Does anyone know what they should be ? Q2, Q3 and Q4 ?
The other issue is the IRS 21844s is in shutdown mode (SD ~ 0.3v). Removing 2SD1302 on the main board, makes the amp play as it should. I've rebuild the DWM3640, was even able to source the MAX transistor...but i still get shutdown mode.
I've checked the voltage +-5v, +12v, +15 everything is fine...
PROT pin on the PS board is sitting at 1v, Not sure if this has to be 15v ?
The amplifier powers up normally but the relay doesn't engage, the pin for it at the PS board is tied to q2, q3, q4. These have been swapped before me, all being npn which is odd, doesn't seem right. At least one should be pnp to pull to ground !? It's not the the relay itself, it works, tried it outside of the board. There is a 1n4148 diode between the relay and the PS board, changing this one did not do anything.
Does anyone know what they should be ? Q2, Q3 and Q4 ?
The other issue is the IRS 21844s is in shutdown mode (SD ~ 0.3v). Removing 2SD1302 on the main board, makes the amp play as it should. I've rebuild the DWM3640, was even able to source the MAX transistor...but i still get shutdown mode.
I've checked the voltage +-5v, +12v, +15 everything is fine...
PROT pin on the PS board is sitting at 1v, Not sure if this has to be 15v ?
Attachments
Are those main board designation or PS board designation ?
There are 2 or 3 different revision for the same amp and there are some slight differences....
Ignoring the designations, is the circuit the same as I posted?
If so, are the types of transistors in the correct locations in the circuit?
If so, are the types of transistors in the correct locations in the circuit?
Ignoring the designations, is the circuit the same as I posted? - YES
If so, are the types of transistors in the correct locations in the circuit? - YES
Some of the resistor values are slightly different but the schematic is pretty much accurate.
At the d51 5v6 zener i only have 2.7v across it.
2SD1302 has 0.6v at it's base....
If so, are the types of transistors in the correct locations in the circuit? - YES
Some of the resistor values are slightly different but the schematic is pretty much accurate.
At the d51 5v6 zener i only have 2.7v across it.
2SD1302 has 0.6v at it's base....
As far as I know, the zener is nothing more than a limiter.
Are the transistors in the right locations in your board?
Are the transistors in the right locations in your board?
Yes, they do...i've rechecked. Seems like almost the AQ20 schematic, except some resistors values are different (not out of tolerance). But the PS driver board is a little bit different, the main board is like the AQ20.
What is the DCV measured across the base and emitter of Q51 and Q52? Black probe on the emitter?
DCV on pin 2 of the PS DB = 2.23v
DCV on pins 1 and 7 of the 8-pin IC on the PS driver board? = both 0.11v
DCV on pins 1 and 7 of the 8-pin IC on the PS driver board? = both 0.11v