Hi everyone.
Some years of not being active on this forum.
Thanks again to Perry Babin for the knowledge gained from his repair tutorial
This time I have a problem with an ALPINE MRV-M500 in protection mode.
The amplifier had the source mosfets shorted and also the output mosfets. I already put them all new and verified that they are in good condition.
But when connected, it starts in protection mode without any current consumption
voltage in PWM with only the power source mosffets soldered (as you see in the pics) :
1 0.0v
2 4.85v
3 0.06v
4 3.61v
5 1.56v
6 3.5v
7 0.0v
8 12.57v
9 0.0v
10 0.0v
11 12.57v
12 12.57v
13 5v
14 5v
15 5v
16 0.0v
Something that I notice wrong is that the terminals of two capacitors are shorted, I already unsoldered the capacitors and the short is not in them, it is in the card.
I even unsoldered the transformer from the power supply and it's not shorted.
I already desoldered all the mosfetts (power source and output) and rectifier diodes. and all those parts are fine.
I would appreciate your suggestions to find the problem
Some years of not being active on this forum.
Thanks again to Perry Babin for the knowledge gained from his repair tutorial
This time I have a problem with an ALPINE MRV-M500 in protection mode.
The amplifier had the source mosfets shorted and also the output mosfets. I already put them all new and verified that they are in good condition.
But when connected, it starts in protection mode without any current consumption
voltage in PWM with only the power source mosffets soldered (as you see in the pics) :
1 0.0v
2 4.85v
3 0.06v
4 3.61v
5 1.56v
6 3.5v
7 0.0v
8 12.57v
9 0.0v
10 0.0v
11 12.57v
12 12.57v
13 5v
14 5v
15 5v
16 0.0v
Something that I notice wrong is that the terminals of two capacitors are shorted, I already unsoldered the capacitors and the short is not in them, it is in the card.
I even unsoldered the transformer from the power supply and it's not shorted.
I already desoldered all the mosfetts (power source and output) and rectifier diodes. and all those parts are fine.
I would appreciate your suggestions to find the problem
Attachments
![IMG_20220425_141726[1].jpg](/community/data/attachments/956/956122-ef80f192758c7d57105eff68830486b6.jpg?hash=74DxknWMfV)
![IMG_20220425_141701[1].jpg](/community/data/attachments/956/956123-aa90027672a5f8d39716aa68cca2170f.jpg?hash=qpACdnKl-N)
![IMG_20220425_141906[1].jpg](/community/data/attachments/956/956124-eca7c1c6126e85a74e7d1bb319f42efd.jpg?hash=7KfBxhJuha)
![IMG_20220425_142131[1].jpg](/community/data/attachments/956/956125-5d034e788025c69740edb5f2a3db3274.jpg?hash=XQNOeIAlxp)
Last edited:
caps rail voltage. those two capacitors are connected to one of the two rectifier diodes (also the 3 terminals of that rectifier diode are shorted) measurement made with the diode unsoldered
The circuit board designations are the markings silk-screened on the board for the various components.
Did you replace the rectifier?
Pin 4 being high is preventing the supply from producing output.
The output driver ICs make these amps uneconomical to repair, for the most part.
If you want to try disabling the protection circuit, removing R9903 may allow the amp to power up. Be careful. The amp may draw excessive current and may cause further damage.
Pin 4 being high is preventing the supply from producing output.
The output driver ICs make these amps uneconomical to repair, for the most part.
If you want to try disabling the protection circuit, removing R9903 may allow the amp to power up. Be careful. The amp may draw excessive current and may cause further damage.
