spl dynamics 1200D no power help

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richardvaio1

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Joined 2014
#1
hi,

I have a spl dynamics amp that when connected to power the protect light blinks then power light blinks this is with in milliseconds. then nothing.

I checked all transistors which seem to be fine.

anyone got a schematic please

any ideas?










thanks in advanced
Richard
 
#2
well... after hours off testing I have my dinner come back to it and turn it on..


it bloody turns on and stays on.

so I put it back in the case with thermal compound and the try it again??


the light flickers from protect- on - protect - on - protect and stays on protect.


im thinking dry solder joint. but I cant find where




kind regards
 
#3
Those S -series SPL dynamics amps have often capasitor problems..(they´re old amps) so check those large caps.

Does it draw excessive current? Also S-series is very sensitive to vibration, so re-check all transistor legs and also try to twist those power transformers if they go shorten.
 
#4
I had many problems with this amplifier..

anyway to cut a long story short.


The amp powers up fine now with the sound driver board taken out.
if i put it back in.. the power light dims and blinks really fast.

iv got on order some transistors for that board which il solder in when i get them.

hope it solves this amp ( night mare )



kind regards
Richard
 
#5
You need to test all your output transistors. if the amp "crowbars" with the driver board in, its because its trying to bring it up to full oscillation and its pulling excessive current.

All it takes is just 1 output transistor that has a slight leakage between drain and source, and its game over...

BTW, this is a maxxsonics design. (or clone)
 
#6
I'm a little sceptic about that maxxsonics, I know personally a guy who has been designing this.........there was supposed to be a led indication for that low voltage shutdown, but the Koreans 'forgot' it --- but anyhow, this is my favourite SPL amp, best korean amp in my opinion. Only thing is that resonation kills it....and caps are on the end of theyre days
 
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#7
mbates14 said:
You need to test all your output transistors. if the amp "crowbars" with the driver board in, its because its trying to bring it up to full oscillation and its pulling excessive current.

All it takes is just 1 output transistor that has a slight leakage between drain and source, and its game over...

BTW, this is a maxxsonics design. (or clone)
Click to expand...



Im on about the bigger board in this amp. Not the power suppy driver board.
Does that change anything ?

Transistors seem fine


Kind regards
 
#8
mika111 said:
I'm a little sceptic about that maxxsonics, I know personally a guy who has been designing this.........there was supposed to be a led indication for that low voltage shutdown, but the Koreans 'forgot' it --- but anyhow, this is my favourite SPL amp, best korean amp in my opinion. Only thing is that resonation kills it....and caps are on the end of theyre days
Click to expand...

Well I am just saying, because that design and PCB layout looks identical to what I see used in maxxsonics amplifiers, hifonics, mb quart, etc..

So, unless all the korean engineers sleep under the same roof and steal from each other, I am inclined to believe its a maxxsonics amp. Unless its the other way around, and maxxsonics gets their designs from someone else.
 
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#9
richardvaio1 said:
Im on about the bigger board in this amp. Not the power suppy driver board.
Does that change anything ?

Transistors seem fine


Kind regards
Click to expand...

I'm talking about the output stage. Not the power supply stage at all. Did you physically remove each and every output transistor and test them one by one? should be open between drain and source in one direction, and a .5v drop the other way. If you tap the gate with your red probe and keep the black probe on the source, it will charge the gate and close the connection between drain and source and you will get as close to .000 as possible.

Trust me, I had to do this 1 by 1 on an MB Quart once just to find out I had 1 leaky output.
 
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