I'm trying to repair Nova IN 15 SUB: hi freq amplifier not working.
I found that pins 12 and 13 of IRS2092 are shortcutted, I changed IRS2092 and IRFBs, checked out all components around (diodes, resistors, capacitors) - everything looks good, but amplifier not working (
Schematics of amp is almost the same as in IRAUDAMP5
Voltages (from GND) on pins are:
1: +5
2: 0
3: 0
4: 0
5: changing from 0 to 3
6: -5
7: -63.5
8: -66
9: -62.9
10: -63.5
11: -69
12: -54.6
13: +2
14: +2
15: +13.8
16: +5.3
Voltage from power supply is +/- 69
Could you point me to documents about debugging amps like that or give any suggestions about?
I found that pins 12 and 13 of IRS2092 are shortcutted, I changed IRS2092 and IRFBs, checked out all components around (diodes, resistors, capacitors) - everything looks good, but amplifier not working (
Schematics of amp is almost the same as in IRAUDAMP5
Voltages (from GND) on pins are:
1: +5
2: 0
3: 0
4: 0
5: changing from 0 to 3
6: -5
7: -63.5
8: -66
9: -62.9
10: -63.5
11: -69
12: -54.6
13: +2
14: +2
15: +13.8
16: +5.3
Voltage from power supply is +/- 69
Could you point me to documents about debugging amps like that or give any suggestions about?
Using your oscilloscope, have you oscillation?
Your voltages show no or little + supply. Ground is centre voltage?
Your voltages show no or little + supply. Ground is centre voltage?
https://www.google.co.uk/search?q=i...vWvMYCQhM:&usg=__O668hhtKsvHqv3GgyI-3b8rGytk=
Will give you a few ideas.
Will give you a few ideas.
You mean to check oscillation on output (pin 13)?
I'm also worrying about + supply, but on top IRFB and power capacitors there are +69V.
On mainboard there are two amplifiers and power supply have two DC circuits providing power for both of amplifiers. Second amplifier (low freq) works correctly.
Yes, ground is centre voltage.
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