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Sapphire XS4600 Amplifier no power

Posted: Mon Nov 02, 2020 12:18 pm
by mbc230
I am new to this forum, but I was wondering if anyone can help me on an XS4600 4 Channel Amp that has no power. The light does not turn on at all. I have checked the voltage on the amp and there is 12 volts from the terminals inside the amp and the IC's have there voltage checked and all show 12V or less on all pins. I have checked the fuses, which are in good shape and no other obvious signs of why there is no power. All the caps look fine and show no bulging on them. I do not see any huge issues so I am wondering if anyone can help me troubleshoot this to get it working. I am lost for words as it is not showing any signs of life. Thank you in advance.

Re: Sapphire XS4600 Amplifier no power

Posted: Tue Nov 03, 2020 9:07 am
by Silverhorse
do you have pics of the inside of the amp?

Re: Sapphire XS4600 Amplifier no power

Posted: Tue Nov 03, 2020 12:48 pm
by mbc230
Silverhorse wrote:do you have pics of the inside of the amp?
What are you looking for in particular? I can take any pictures that you need if there is a specific thing you want to see. Thank you for your reply.

Re: Sapphire XS4600 Amplifier no power

Posted: Tue Nov 03, 2020 1:13 pm
by Silverhorse
an overview of the board would be a good start.

Re: Sapphire XS4600 Amplifier no power

Posted: Tue Nov 03, 2020 1:57 pm
by mbc230
Silverhorse wrote:an overview of the board would be a good start.
Here you go. I hope these are a good start. Thank you.

Re: Sapphire XS4600 Amplifier no power

Posted: Wed Nov 04, 2020 9:47 am
by Silverhorse
Main Board 2.jpg
can you take a more detailed photo of this resistor? It think it's burnt.

Re: Sapphire XS4600 Amplifier no power

Posted: Wed Nov 04, 2020 1:55 pm
by mbc230
Silverhorse wrote:
The attachment Main Board 2.jpg is no longer available
can you take a more detailed photo of this resistor? It think it's burnt.
I noticed that too and tested it and tested fine with 12V running through it. It looks like it was an issue with something else that I am trying to track down from the no power issue. I feel it is something else, but it is not obvious. I know it looks burnt, but it is isn't.

Re: Sapphire XS4600 Amplifier no power

Posted: Sun Nov 08, 2020 8:40 am
by Silverhorse
Can you measure the resistor with your multi meter?

Re: Sapphire XS4600 Amplifier no power

Posted: Tue Nov 10, 2020 2:50 pm
by mbc230
Silverhorse wrote:Can you measure the resistor with your multi meter?
I measured it and the reading I got was "0.04". Is that within spec?

Re: Sapphire XS4600 Amplifier no power

Posted: Mon Nov 16, 2020 8:59 am
by Silverhorse
I think that the minimum damage is a blown power supply.
Do you have good soldering skills to repair this?

Re: Sapphire XS4600 Amplifier no power

Posted: Mon Nov 16, 2020 2:00 pm
by mbc230
Silverhorse wrote:I think that the minimum damage is a blown power supply.
Do you have good soldering skills to repair this?
I am not too bad, but what would it take to fix the blown power supply? Which one is it? Is it one of the ones that are coils? There are two of them. Thank you for your help. Why would you think it is a power supply? Thanks again.

Re: Sapphire XS4600 Amplifier no power

Posted: Thu Nov 19, 2020 9:15 am
by Silverhorse
you can start with changing the 4 transistors with the 4 resistors that are connected to it. Each channel has 4 of these. You can start with only the 4 of the side who has burning marks and see what happens then.

There is a (good) possibility that after this repair attempt its not working and you have to take it further. If you want this fixed at the lowest cost than its better to take it to a pro repair shop. If you want to experiment and have fun than go for it!

Re: Sapphire XS4600 Amplifier no power

Posted: Thu Nov 19, 2020 6:04 pm
by mbc230
Silverhorse wrote:you can start with changing the 4 transistors with the 4 resistors that are connected to it. Each channel has 4 of these. You can start with only the 4 of the side who has burning marks and see what happens then.

There is a (good) possibility that after this repair attempt its not working and you have to take it further. If you want this fixed at the lowest cost than its better to take it to a pro repair shop. If you want to experiment and have fun than go for it!
Well I am curious as to why I would buy those fets and replace all them when they test just fine with 12 Volts going through them. They all read the same. I am looking for common things what would cause a no power condition. I do not want to take it to a shop, but fix it myself. I am able to be taught just need a little guidance. Thank you.

Re: Sapphire XS4600 Amplifier no power

Posted: Fri Nov 20, 2020 8:04 am
by Silverhorse
you have 4 big black rail caps, what voltage do you measure there between the + and - of every single cap when the amp is powered up?

Re: Sapphire XS4600 Amplifier no power

Posted: Fri Nov 20, 2020 8:15 pm
by mbc230
Silverhorse wrote:you have 4 big black rail caps, what voltage do you measure there between the + and - of every single cap when the amp is powered up?
I measured 12 volts between all caps.

Re: Sapphire XS4600 Amplifier no power

Posted: Sun Nov 22, 2020 10:33 am
by Silverhorse
12v is not ok.
On youtube you can find some excellent tutorials on how to test a transistor with a simple multi meter. After that you can start with the 6 power supply transistors.

Re: Sapphire XS4600 Amplifier no power

Posted: Sun Nov 29, 2020 10:48 am
by mbc230
Is there someone out there that can give me some direction based on the information I provided in this post on where to start? I have been chasing my tail on this. My background is limited with the electronics testing part of this. This amp has a no power condition. I have checked all components, but not sure about the basic electronic aspect of things, which is what I am struggling with. I am pretty decent with soldering and basic things with using the voltmeter, but tracing the issue is where I fall short on. Thank you very much and much appreciate anyone who can help.

Re: Sapphire XS4600 Amplifier no power

Posted: Mon Dec 21, 2020 4:55 pm
by mbc230
mbc230 wrote:Is there someone out there that can give me some direction based on the information I provided in this post on where to start? I have been chasing my tail on this. My background is limited with the electronics testing part of this. This amp has a no power condition. I have checked all components, but not sure about the basic electronic aspect of things, which is what I am struggling with. I am pretty decent with soldering and basic things with using the voltmeter, but tracing the issue is where I fall short on. Thank you very much and much appreciate anyone who can help.
So I did some testing on the Transistors and educated myself on how to test them and what each of them are. I was on the power side and I have six P55N06 and two SF163 Fet's. I started with the P55N06 and tested those with the Gate being the left pin, the middle pin is the Drain and the pin to the right is the Source. When I put my voltmeter to testing a Diode it reads a "1", but when I apply the Negative lead to the Source pin and the Positive to the Drain I get a reading. I was under the impression it would be a 1 as there is not suppose to be a connection between those pins. My meter is not the best, but it does work so I hope I am doing this right so in my opinion I think I need to replace them. What do you think? I have not tested the SF163 fets yet since I can not find the specs for them. If anyone can help I would be greatly appreciated. I am not too savy, but can be taught. Thank you in advance.

Re: Sapphire XS4600 Amplifier no power

Posted: Tue Dec 29, 2020 11:29 am
by Silverhorse
these are good videos I think that give more insight.
https://www.youtube.com/watch?v=z-9wCw7J6QQ
https://www.youtube.com/watch?v=R0Uy4EL4xWs

If there are burnt marks you can be 100% sure that the component is broken. The best and most logical way is to start there.
Start wit replacing all the P55n06 transistors and the corresponding gate resistors. Always replace them together with fet's from the same production run.
The SF163 is not a transistor but a diode.

Re: Sapphire XS4600 Amplifier no power

Posted: Sun Jan 03, 2021 12:12 pm
by mbc230
Silverhorse wrote:these are good videos I think that give more insight.
https://www.youtube.com/watch?v=z-9wCw7J6QQ
https://www.youtube.com/watch?v=R0Uy4EL4xWs

If there are burnt marks you can be 100% sure that the component is broken. The best and most logical way is to start there.
Start wit replacing all the P55n06 transistors and the corresponding gate resistors. Always replace them together with fet's from the same production run.
The SF163 is not a transistor but a diode.
Thank you for all your help and it is now becoming more clearer with all the effort I have put into this. The only thing I know I need to purchase is a good DMM. The one I have is not the most intuitive so I think it is time to invest in a new one. What do you think is a good one for the money? I am looking at a Fluke 83 DMM and want to spend about $100.00 as I see them used all over the net. The 87 and 89 are just our of my price range. What do you think? I am also going to purchase all the parts I need to swap out the fets and gate resistors. I am trying to buy the gate resistors and I am using the digikey color code calculator and came up with 10.7 ohms .10%, but I am not able to find a replacement and lost on how to purchase the resistors. Can you provide me some direction on how to select the right ones through digikey? Can I just buy a resistor kit? You have pushed me to do a lot more learning and I appreciate that even though I am still a little fuzzy and unsure as I am a novice, but I am treating this as a learning experience. Thanks again.

Re: Sapphire XS4600 Amplifier no power

Posted: Tue Jan 05, 2021 1:39 pm
by Silverhorse
Basic multi meter is ok, Fluke is good quality.
P55N06 works normally with 33 Ohm resistors.
Don't know if you will find new P55N06's. If not you can replace them with IRFZ48 resistors, but then you have to use 330 Ohm resitors. 5% is OK.

part numbers:

- IRFZ48VPBF
- PPC330BCT-ND

but before you order, take a good detailed picture of a good (not burnt) resistor than we can see the original value.

Re: Sapphire XS4600 Amplifier no power

Posted: Thu Jan 07, 2021 3:03 pm
by mbc230
Silverhorse wrote:Basic multi meter is ok, Fluke is good quality.
P55N06 works normally with 33 Ohm resistors.
Don't know if you will find new P55N06's. If not you can replace them with IRFZ48 resistors, but then you have to use 330 Ohm resitors. 5% is OK.

part numbers:

- IRFZ48VPBF
- PPC330BCT-ND

but before you order, take a good detailed picture of a good (not burnt) resistor than we can see the original value.
I picked up a Fluke 83v for $100 bucks so I am happy about that. I found these below:

FDP55N06 @ digikey - Are they the same?

I took a very good picture. Thank you.

Re: Sapphire XS4600 Amplifier no power

Posted: Fri Jan 08, 2021 12:58 am
by Silverhorse
FDP55NO6 is a good replacement I think.
The color code of the resistors is difficult to see (I'm not so good with colors) I think it's orange / black / brown / gold than it is a 30 Ω 5% resistor.
Cut one leg of one resistor and than you can measure the resistor value with your multi meter. It should read 30 Ω.

Re: Sapphire XS4600 Amplifier no power

Posted: Sat Jan 09, 2021 6:36 pm
by mbc230
Silverhorse wrote:FDP55NO6 is a good replacement I think.
The color code of the resistors is difficult to see (I'm not so good with colors) I think it's orange / black / brown / gold than it is a 300 Ω 5% resistor.
Cut one leg of one resistor and than you can measure the resistor value with your multi meter. It should read 300 Ω.
It is actually a Brown Black Violet Gold Violet and it is a 5 band resistor. The multimeter I have purchased has blown fuses so I will check it when I get the new fuses. Thank you.

Re: Sapphire XS4600 Amplifier no power

Posted: Tue Jan 19, 2021 8:05 pm
by lilviper
mbc230 wrote:
Silverhorse wrote:FDP55NO6 is a good replacement I think.
The color code of the resistors is difficult to see (I'm not so good with colors) I think it's orange / black / brown / gold than it is a 300 Ω 5% resistor.
Cut one leg of one resistor and than you can measure the resistor value with your multi meter. It should read 300 Ω.
It is actually a Brown Black Violet Gold Violet and it is a 5 band resistor. The multimeter I have purchased has blown fuses so I will check it when I get the new fuses. Thank you.
Fuses are typically for the current measurement, shouldn't affect the resistance measurement.

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