Hey Perry I have a power 360a2 that I am having trouble with. Board # PC-2065-D. It had a faulty channel putting 24 vdc to the right speaker terminal. I replaced the output fets, emitter resistors, and the gates. Still same problem. I repaired 2 Power 450S's last night with the same issue. They had SMD resistors in the channel out of tolerance. I dont seem to find any out of tolerance. The fets are puttung 24 vdc out of the drains to the terminal. Any ideas?
It's probably not a good idea to address me directly. It may make others hesitant to help.
With the black probe on the source and the red probe on the gate of the output transistor in the defective channel. What voltage do you read for each of the outputs?
Wit the black probe on the amp's ground terminal, what is the DC voltage on the bridging terminal of the defective channel?
For both of these, polarity is important.
With the black probe on the source and the red probe on the gate of the output transistor in the defective channel. What voltage do you read for each of the outputs?
Wit the black probe on the amp's ground terminal, what is the DC voltage on the bridging terminal of the defective channel?
For both of these, polarity is important.
Sorry about that Perry, kinda got into the habbit.
Q225 IRF540: 2.7 vdc
Q224 IRF9540: -.056 vdc
Q218 IRF540: 2.7 vdc
Q219 IRF9540: -.040 vdc
Bridging terminal of defective channel: -20.65 vdc
Post the DC voltage on all of the terminals of Q211, Q222 and Q213. Place the black probe on the emitter of each and note the polarity if it's negative.
Correct me if I am wrong you want the red probe measuring the terminals while the black probe is on the emitter?
Q222: 22.78 vdc
Q222: 3.427 vdc
Q222: 2.788 vdc
Q211: .518 vdc
Q211: .514 vdc
Q211: .526 vdc
Q213 I am unsure the numbers are all smeared together on the board and very hard to read I am PRETTY sure I am reading the right one.
Q213: .351 vdc
Q213: .003 vdc
Q213: .635 vdc
You will have only 2 voltages per transistor. If you already have the black probe on the emitter of each one, the voltage (if you also place the red probe on the emitter) will be 0.000v.
Q222: 20vdc
Q222: .640 vdc
Q211: 12.61 vdc
Q211: 0.00 vdc
Q213: -.076 vdc
Q213: -.627 vdc
I think I did it right, hopefully.
I was getting inconsistant readings, so I changed with a new 1A and now it reads 12.61vdc on 2 terminals and 0.00vdc on the other.
The amp still has the same issue.
Just doing some random checking and the + terminal of C215 has 36 vdc, and C115 from the other channel has 0 vdc
Are R274 and R275 within tolerance?
If you connect a speaker or dummy load, does the DC drop to 0v on the speaker terminals?
If you connect a speaker or dummy load, does the DC drop to 0v on the speaker terminals?
R274 and R275 read 20.3 ohms in the circuit. Do you want me to remove them to check?
No the dc voltage on the terminal does not go away when a speaker is connected, it sparks and makes the speaker jump. I held my meter on the terminal while hooking up the speaker and the dc voltage stays
I removed R274 and R275 from circuit and tested. R274 read 20.3 ohms, and R275 read 22 ohms, so I just replaced them both with new resistors.
The amp has the same issue.
The amp has the same issue.
I am not sure on R260 it reads 618 and is suppose to be 621. I dont know the tolerance on it. I have 620 and 622 but no 621's.
Lifting the legs on Q213 made no difference in the dc voltage on the terminal. Since I already had 2 legs off I just removed and replaced it with a new one.
How do you determine if a SMD transistor is leaking? Same as a ouput or power supply fet?
Ohms or VDC?
What's the resistance from the source of one of the IRF540s to the base of the Q223?
There's no difference between SMD and other transistors except the case. They check the same way (for whatever type of transistor it is).
There's no difference between SMD and other transistors except the case. They check the same way (for whatever type of transistor it is).
BASE?
I thought they had a gate, source, and drain like a regular fet. I am unsure which is the base?
- Status
- Not open for further replies.