SinusLive SL-A1500 help needed.

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Perry Babin

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Joined 2003
bcae1.com
The voltage on the op-amp looks OK.

I don't quite understand the voltage you have on the speaker terminals. To clarify, answer these.

With speaker connected:
voltage just before pop?
voltage just after pop?

No speaker connected:
voltage before pop (when it would pop if it had a speaker connected)?
voltage after pop?
 
G

Ground Zero

Member
Joined 2007
Hello Perry

Thanks a lot for your help :)

With speaker connected, i have measured
voltage just before pop? 0 VDC (the amp have the protect led blinks) the amp seems do different test and go to the green red in the same time pop appears.
voltage during pop 2.43 VDC or a little more...it varies to 2.71 max
voltage just after pop? it down to -99.5mvdc

No speaker connected, i have measured
voltage before pop: 0VDC
voltage after pop:it down from 2.43vdc to -134.2mv
and gradually increases to -198.2 after one minutes and after 2 minutes
i have -200mv and seems stable

Have you got an idea of the problem please ? :confused:

for the test i use a power supply smps 13.8vdc 12A regulated and i put a 10 A fuse on the b+ battery of the amp but before i use a 5A fuse and the amp blow it ....do you think it's normal ?

Thanks for your help Perry :)
 
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Perry Babin

Member
Joined 2003
bcae1.com
From what I can tell from your description, it appears that the output is being driven to 2+v after the power supply starts but is quickly brought down when the mute delay ends. Can you confirm by measuring the voltage on the mute pin of the driver board to determine if the end of the 2+v is precisely when the mute signal transitions from high to low?
 
G

Ground Zero

Member
Joined 2007
Thanks Perry :)

Ok i understand now, the driver board and "modu 1" are the same things :)

i have search and i have no markings on the driver board (modu1) or on the main board that indicate the pin number or function....but i don't know if it can be useful :confused:but on the driver board "modu1" the version is: XM03-REV.A

i put my black metter on the negative speaker and the positive on the mute pin, is it right ?

i use the service manual and i found the mute pin "number 3 on the manual" but i don't know if it's the same amp version that i have :confused:

but i thing to find the good pind because i found the pin number 5 who have 5VDC and it is on the opposite of the mute pin so i find it :)

I have this result for the mute pin: when the led red do test procedure "before the pop noise" i have 13.09VDC and when the pop noise appears the voltage go down extremely fast " 1 second or less" and i have 0VDC on the mute pin, but i have mesured 3.2mv

I am really lost :confused:

Have you got an idea Perry please ?

Thanks a lot :)
 
G

Ground Zero

Member
Joined 2007
Hello Perry :)

No i haven't scope and yes the voltage drops from 2+v to 0v on the output at the same time the mute goes to ground :confused:

do you think the modu1 is defective ? or i must change all mos-fet ?

I don't know if it's important but there is a strange thing that appear when i power on the amp..i can here a little noise like a switch who do on/off, on/off extremely fast during the start :confused: i have difficult to focus where is this noise on the main board :confused:

but on this photo you can see a coil who comes and smell hot :confused:

An externally hosted image should be here but it was not working when we last tested it.


do you think it's normal ?

Thanks for your help
 
P

Perry Babin

Member
Joined 2003
bcae1.com
The filter inductors for these amps run hot. They have too much loss. I had some made that use molypermalloy cores and they run MUCH cooler. They're also less likely to short (a problem in the Massive amps) because they have fewer windings so no windings overlap on the core.

At this point, I think you need to measure the DC voltage across legs 1 and 3 of each of the output transistors. Do any have more than ~1v. It's important that you measure the voltage when the output has 2v on it. This is irrelevant at any other point in time.
 
G

Ground Zero

Member
Joined 2007
Ok Thanks Perry :)

So that's i have mesured, when i here the pop noise "same time i have 2.vdc"

Mos-fet 1
Pins 1-3: 4.3vdc "pop noise" and go to 5.2vdc

Mos-fet 2
Pins 1-3: 5.2vdc

Mos-fet 3
Pins 1-3: 4.2vdc "pop noise" and go to 5.2vdc

Mos-fet 4
Pins 1-3: 2.4vdc "pop noise" and go to 5.5vdc and finally 5.2vdc

Mos-fet 5
Pins 1-3: 5.8vdc "pop noise" and 6.8vdc and 0vdc and finally 5.2vdc

Mos-fet 6
Pins 1-3: 1.8vdc "pop noise" and 6.8 vdc and 0vdc and finally 5.3 and 5.2vdc

Mos-fet 7
Pins 1-3: 5.8vdc pop noise and 6.8vdc and 5.3vdc and finally 5.2vdc

Mos-fet 8
Pins 1-3: 5.0vdc pop noise and 6.2vdc and 5.3vdc

results are really strange :confused:
 
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