This one is strange, everything seems to be working, even proper current draw. It came out of protection and had full clean audio.
The amplifier starts up like all these do, draws currents then starts, draws 1amp at idle, yet the red protection light is on.
Regulated, rail present. No excessive current.
This is the same voltage latter as the previous amplifier I believe.
Some help.with this is issue would be welcome.
The amplifier starts up like all these do, draws currents then starts, draws 1amp at idle, yet the red protection light is on.
Regulated, rail present. No excessive current.
This is the same voltage latter as the previous amplifier I believe.
Some help.with this is issue would be welcome.
Attachments
Last edited:
Check to see if Q29 and Q30-BC817 are leaky or shorted.
Check the DC voltages around same and post.
Check the DC voltages around same and post.
No shorts, or leaking. From main ground.
Q30
B.) .006
C.) 12.38
E.) 0.00
Q29
B.) .650
C.) .105
E.) 0.00
Q30
B.) .006
C.) 12.38
E.) 0.00
Q29
B.) .650
C.) .105
E.) 0.00
So after that. Since the amp has rail and regulated voltage present. I started to look at the ladder circuit and drive. Replaced c61-62-63 100nf caps and the 12-24-12 diodes same result just stuck in protection?
If you have all operating voltages and audio the amp is not in protection.
Either the Green LED has failed or the mute1 signal from the microcontroller has not been asserted.
Determine if LED1 is good. Monitor the DC voltage from power ground to R72-100kΩ(opposite side of Q30's base) through power up. Do the same with R53-100kΩ.
Either the Green LED has failed or the mute1 signal from the microcontroller has not been asserted.
Determine if LED1 is good. Monitor the DC voltage from power ground to R72-100kΩ(opposite side of Q30's base) through power up. Do the same with R53-100kΩ.
Amp is in protection. Red led lit only. No audio when it's in this state.
It came out and the green power led lit up, the amp then had audio, it went right back to the protection state. Drawing 1amp of current.
It came out and the green power led lit up, the amp then had audio, it went right back to the protection state. Drawing 1amp of current.
Last edited:
If you lift D33 and D34-1N4148, one at a time, does the amp come out of protection?
Measure the DC voltages around IC14,IC15-IRS20957 with respect to power ground.
Measure the DC voltages around IC14,IC15-IRS20957 with respect to power ground.
IC14
1) 10.38
2). 1.136
3) .444
4) .010
5) .006
6) 5.158
7) .920
8) 12.98
9) .012
10) .011
11) 13.29
12) .025
13) 36.79
14) 36.80
15) 51.99
16) 36.81
1) 10.38
2). 1.136
3) .444
4) .010
5) .006
6) 5.158
7) .920
8) 12.98
9) .012
10) .011
11) 13.29
12) .025
13) 36.79
14) 36.80
15) 51.99
16) 36.81
Last edited:
IC15
1) 10.39
2) 1.095
3) .458
4) .006
5) .001
6) 5.147
7) .911
8) 12.97
9) 0.00
10) 0.00
11) 13.45
12) .023
13) 36.75
14) 36.75
15) 51.89
16) 36.73
12) .023
13) 48.00
14) 47.98
15) 62.49
16) 47.97
I noticed the last 4 changed from 36. To 48 after I restarted the unit on both ic's
1) 10.39
2) 1.095
3) .458
4) .006
5) .001
6) 5.147
7) .911
8) 12.97
9) 0.00
10) 0.00
11) 13.45
12) .023
13) 36.75
14) 36.75
15) 51.89
16) 36.73
12) .023
13) 48.00
14) 47.98
15) 62.49
16) 47.97
I noticed the last 4 changed from 36. To 48 after I restarted the unit on both ic's
Last edited:
Lift, in pairs D16,D24 and D17,D25 . You may need to have all four diodes to allow the 10.3 Vdc on Pins 2 of IC14 and IC15 to reassert allowing the IC's to come out of CSD (Current Shutdown).
Check the voltages around Q28-2N7002 and Q19-BC817. Also, look at the Vdc on the anode of D14 and either side of R49-1KΩ. There may be a failed transistor or diode in circuit,
Check the voltages around Q28-2N7002 and Q19-BC817. Also, look at the Vdc on the anode of D14 and either side of R49-1KΩ. There may be a failed transistor or diode in circuit,
When lifted d16,d24 ic15 pin 2 had it's 10.2vdc on it but when I lifted d17,d25 IC14 pin 2 only had 5.3vdc on it.
R49 has 13.3v and .043vdc.
D14 has 3.332 and 2.785vdc.
Amplifier stayed in a protection.
I also noticed that r24 stated to smoke? They both measure 10.1ohms and have +-17.86vdc on them.
R49 has 13.3v and .043vdc.
D14 has 3.332 and 2.785vdc.
Amplifier stayed in a protection.
I also noticed that r24 stated to smoke? They both measure 10.1ohms and have +-17.86vdc on them.
Last edited:
It appears the issue is in the IC14 circuit or the IC itself. Check Q103,104-AOT410, Q101,102-2045ES, C135,C137-22uF/16v.
Not sure what is causing R24 to smoke. Are you seeing the +/-17 volts?
Not sure what is causing R24 to smoke. Are you seeing the +/-17 volts?
After checking the components. I didn't see anything wrong with any of them so I changed the chip now the amp just draws current.
I t gets to it's last cycle before it generally drops current and turns on, and just stays drawing current.
I t gets to it's last cycle before it generally drops current and turns on, and just stays drawing current.
Ok, so I left it go for awhile and the current did drop. But the r24 is burning up. So did r85, and q18 is getting hot as well.
Ok, so I left it powered up for awhile longer and the current did drop. R23, and r24 is burning up. I changed them. So did r84, r85, and q17, q18 is getting hot as well. There is only +-10.5vdc. After I shut it down and powered it back up the +-18.3vdc was back? And the resistors and transistors didn't seem to get hot. I have 90.vdc of rail on the side I did not change the ic on, the other side I changed is jumping around fr 50-63-71-43-ect .....the heating of those components seems to have stopped for now that the regulated is back to the +-18.59vdc.
Last edited:
One of the following IC's maybe loading down the -17 volt rail. Check them one by one.
IC1-NJM2060
IC3,4,5,6-NJM4580
IC18-TL072
I would replace Q18-BCP53
IC1-NJM2060
IC3,4,5,6-NJM4580
IC18-TL072
I would replace Q18-BCP53
I also changed the ic for the 90v of rail and now have 47.65 per side? Zd3 should only be 12vdc from main ground on one side correct? I have 36v on both sides?
The amplifier is back to +-17.4vdc. ill go through all the opamps.
The amplifier is back to +-17.4vdc. ill go through all the opamps.