power acoustic plasma sphere not very plasma-rific

[scampo77]

i managed to get the audio parts working on this power acoustik TS620-2 but i cant figure out why the plasma sphere bulb wont come on and im not sure how it works or where i should start testing.

there is no ac or dc voltage driving the bulb im not sure if im looking for ac or dc here, neither would surprise me. i do have a good ground going from the small circuit board. there is also a third brown wire. that connects the small PCB to the motherboard via 2 diodes. i have no power here and no power on the other side of the 2 diodes either. i do have full 12v to from the red wire coming from the big diode at D2 which i suspect is the power source.

there is no obvious soot or cracked solid state parts and pieces and the amp itself is working perfectly.

[scampo77]

while i was trying to chase back the brown wire i bypassed one of the diodes and the sphere lights up but it is not in time with the music and you can hear it in the audio. the same thing happens with the other diode. it shuts off as soon as i take away the test meter

so atleast the light itself is still lighting up.

[Perry Babin]

I can't tell you how to repair it but you should be aware that there is at least several hundred volts on the wire that goes to the plasma tube.

[scampo77]

i figured there would be a lot and im being very careful. you dont have any idea of anything i might check? what if i take a lot of pictures?

[Perry Babin]

The older version had problems with blowing the transistors. They also developed bad solder connections but I think those problems were eliminated when they began using two transistors. I haven't had to repair one of the power supplies with two transistors.

See if you can get a schematic diagram from PA. It probably won't show the supply but you won't know until you get the diagram.

[scampo77]

is it normal to get this sort of information from a manufacturer like this? i mean is it worth while tracking them down and calling them? do you think they would be willing to give or sell me this information?

is there really nothing else i can check or chase around? what about this brown wire? should there be voltage to it? should it be pulsating?

[scampo77]

i have another one of these amps that is identical. is it possible to take any useful information/measurements from the working one?

[Perry Babin]

The brown wire is signal from the audio output (rectified by the diodes).

Some of the manufacturers will provide technical documents. Others won't won't provide any technical support.

Power acoustik will provide schematic diagrams for amplifiers that are out of production. Don't mention my name. They're likely to become less helpful.

[scampo77]

hahhahahahahahah!!!!!!! oh man, ok i won't mention you, thats super funny

[Perry Babin]

I don't know enough about the circuit to know if you can compare the two. It may be that it uses the audio signal to drive the transistors which pulse the transformer to produce the high voltage (sort of like the ignition coil in a car). If that's the case, there wouldn't be much to compare.

You could pull the transistors and carefully test them but I don't know what else you could do.