Alpine mrvm500.

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
R

rrae

Member
Joined 2011
Alpine mrvm500.
Amp with new output transistors, new ic3601 (from PP) and output fet drivers.
Here is output signal, from what i get such spikes? ic3601 could be bad? No load connected. Idle current 700mA
 

Attachments

  • output.jpg
    output.jpg
    534.3 KB · Views: 142
Last edited:
R

rrae

Member
Joined 2011
Its 100Hz tone, just zoomed out, to see better what i mean.
I edited post, its without any load.
Turned again amplifier on and had clean signal for 10 seconds, after that again same thing. With load i dont have any output, than sometimes spike.
 
Last edited:
R

rrae

Member
Joined 2011
All measurements without load, without input signal. Ground terminal as reference.

1. 10,2
2. 5,1-5,2 (swinging very fast)
3. 0.01
4. -0.00
5. -54,16
6. -50,76
7. -54.8
8. -55.93
9 .-55.94
10. -55.95
11. -46,29
12. -55,8
13. 0.003
14. 0.003
15. 15.25
16. 2.27

Pin 2;15;16.
 

Attachments

  • ic3601#.png
    ic3601#.png
    31 KB · Views: 111
R

rrae

Member
Joined 2011
Amplifier is acting weird. I just powered up for the first time today, measured and had 10.2V on pin number 2. of IC3601. But the pin 15. and 16. measurements left the same for those pins:
15. 15.25
16. 2.27
After half minute its again pulsing.
Q3204:
C: 0.00
B: 4.97 (stable)
E: 5.039
Q3210:
C: 5.1-5.2 (this one is pulsing same as pin number 2. of ic)
B: 0.00
E: 0.00

Maybe output transistors are bad as 15. and 16. is high and processor is shutting down IC3601? Why i had solid 10.2V when i first time powered amplifier, i tried restart it several times, but after never had 10.2V, just pulsing 5V.

EDIT: I started to probing around IC3601. I have R3608 which measures in circuit 2K7, it should be 3R9. I will try to desolder from pcb and check it.
 
Last edited:
R

rrae

Member
Joined 2011
R3608 was bad. Replaced. First when i received amplifier, it had blown outputs, shorded ZD4901 and Q4901.
Now i have solid 10.2V on pin 2. of ic.
But 15. and 16 is still high.
15. pulsing from 12.0-12.1V
16. 0.7V

Seems like D3601 is open. What to replace for testing?
 
Last edited:
R

rrae

Member
Joined 2011
For testing replaced with 4148. Amp is producing clean sine wave output without load @ output terminals. I will clamp on case and test with load. Seems like i managed to get it working.
But voltages on 15. and 16. are confusing me. With multi meter i have 170V on 16. and 220V (!) on 15. Just cant be right. I will recheck with oscilloscope.
 
Last edited:
M

mikep28

Member
Joined 2015
I can confirm that the IRS20956 I Got from UTSOURCE works in place of this IC. I tried it in a working amp.

Now onto your problem. I have same thing on another amp. Except I don't get the pulsing. All voltages looked good except same as you pin 15 and 16. You get 15vdc (+) and like 2.9 VDC (+) on pin 16?
 
R

rrae

Member
Joined 2011
1. 10.25
2. 10,24
3. 0,0
4. 0,0
5. -52,88
6. -49,68
7. -53.8
8. -54.82
9. -54.84
10. -44.63
11. -43,5
12. -54,73
13. 188.98
14 149,19
15. 196,86
16 153.4

This is with my multi meter. i checked pins from 13-16 with oscilloscope.
There is square signal on those pins, they are not oscillating (with no input signal).
Amplifier is producing output when loaded - just quick test before clamped on heat sink.
I assume that its just multi meter glitch and its goes crazy because of PWM signal?
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom