JBL Synthesis S7150 Capacitors - WILL I KILL MYSELF? HELP!!!!!!!!!!!!

[porschecab]

I've been around audio for close to 20 years now, but I haven't, nor really want to, work on gear myself.
However, I recently picked up a S7150 and of course that person shipping it didn't pack it correctly (shocker...) and it has some damage.
Two of the bindings posts are broken/loose, really just the black plastic boxes around them, but those hold the posts, so they are necessary.

I removed the top to see what I could see - a reviewer stopped by my shop and asked 'do you love your family?' but I hadn't a clue to what he was talking about. Apparently touching certain parts of the amp can kill or knock me on my arse. So, I stopped. The amp has not been plugged in for at least two weeks now - but as you see in the photo, what is it that I can not or should not touch - the toroidal transformers or the black caps on each amp board, or both, or something else?

I have read ways to drain the power, but that really isn't for me. Any suggest that will keep me alive?

Thanks in advance,
Dan


6906769068

[hjames]

There's probably nothing at that kind of potential in an amp, but if in doubt,
use a voltmeter and check for voltages before sticking your fingers in there -
its science, not magic.

If you are going to work on it, you need some kind of continuity checker/Ohm meter anyway ...

Coils don't hold voltage - caps can - but its probably not the risk you presume ...

Big sparks were often found in the caps and transformers used in old CRT style televisions -
high voltage was used to move the dots around the screen. But not silicon based audio gear.

[just4kinks]

Tube amps are the killer, because they run at a few hundred volts. Typically the highest voltage in solid state amps is the 120V (for the US) mains voltage.

Also most amps have bleeder resistors on the supply caps to drain them after the amp has been switched off for a minute or so.

[Fitero]

I keep a 100w incandescent bulb in the drawer which I have soldered some leads to. I use it to drain the large value caps on equipment before working on it.

[NickH]

You might ha e 150 vdc from rail to rail. But as other mentioned there more then likely browser resistors o. The rails. If the unit hasn't been powered up in a few day your going to be fine. Electrolytics naturally drain from internal resistance over time.


I use a 1p to 20 ohm resistor to drain most all caps I come across when working on amps.


Nick

[TabbMulroy]

As per my experience,there is probably nothing at that kind of potential in an amp. You must use a voltmeter and check for voltages.
its science, not magic.
If you are going to work on it, you need some kind of continuity checker/Ohm meter.
Coils don't hold voltage caps can but its probably not the risk you presume.
Big sparks were often found in the caps and transformers used in old CRT style televisions high voltage was used to move the dots around the screen.

[audiomagnate]

I keep a 100w incandescent bulb in the drawer which I have soldered some leads to. I use it to drain the large value caps on equipment before working on it.

Great idea!

[Flodstroem]

Iĺl newer forget the good old days, in the 60th when working on my bass amp. Last session I discover there was som kind of open circuit or bad solder or some loose cable some where in the tube amp. I took the amp with me to my home for a check and for a repair. When at home I turn the amp upside down an unscrewed the bottom plate. And with the screwdriver still in my hand I tried to find some loose circuits. I tapped on several components hopefully for to find a bad solder or loose cable. Now, for to find the fault I had set the power switch to on and a also had a speaker connected to the amps output.. Finally I came to the HV caps that filters the 500V+ anode voltage. Having a secure grip on the chassis with my left hand I began tapping on the positive terminal on the anode capacitor NOT remembering that the screwdrivers handle also was made of metal!!?? I had a total muscle contraction in both arms an my right hand throw the screwdriver right at the rooms window. This was the worst electrical chock I had ever experienced I can assure you, :eek:
I had pain in my arms for several days after that issue........ :crying:

Folks, be carefully when working on powered amps.......