JBL CS200.1 blows fuses on power up

[tylerlough]

Well I really don't think that I'll be able to fix it my self but I can try.
It's a 337 watt mono sub amp that is 2 ohm stable. I think I only paid $90 new.
The problem is it doesn't work right.

1. It turns on but no power light
2. A fake siren like noise comes out of sub
3. 3 sec later Fuses blows and noise stops
4. replace fuses
5. back to one

I think it might be the output fets but I'm not sure how to test them.
The likely cause of failure is overheating, don't know what all this would have damaged.

Look at that nice factory solder job, but it is made in china

[japlytic]

Re: JBL CS200.1 blows fuses on power up

It seems a little bit difficult for me to judge this situation here, but I will try my best.

The amplifier with no power light and making a sound from a speaker shows the amplifier section (and power supply section) is apparently OK (even though I can see a differently branded TIP36 transistor).

There appears to be residue of something which has dried up; some of it is near the large-value electrolytic capacitors (be sure to clean it up with alcohol before performing repairs!). The large transformer is the DC-DC converter, and the sound you described is most likely to be caused by bad electrolytic capacitors loading down the output from the DC-DC converter.

The first thing to do is unsolder all 7 large electrolytic capacitors (taking notes first!) and measure them with an ESR meter and a multimeter. If you get a low-resistance reading with a multimeter (<10 ohms), the large electrolytic capacitors need to be replaced (What are the series of the Su'scon electrolytic capacitors? Also, what other brands of electrolytic capcitors are used in this unit?)

If the fuse still blows, despite carefully replacing the electrolytic capacitors, unsolder each high-power transistor, MOSFET and high-power rectifier (taking notes first!) and test them with a multimeter. If there are no shorted devices, put them back into the circuit.

Also check the high-wattage resistors as well.

I don't understand why such a premium brand has used cheap components!

[Per Hansson]

Re: JBL CS200.1 blows fuses on power up

Looks like water has entered the unit, I got a broken LA Sound amp just like that, it had blown all it's mosfets on one side, replaced them and then it ran just fine... Using it in my car now... (blown them as they fell apart when I removed the matal parts holding them to the heatsinks LOL)

So check the Q9, Q12 and Q15 Mosfets after you check the capacitors, looks like they have become warm to me...

[kc8adu]

Re: JBL CS200.1 blows fuses on power up

i would clean up any water damage.
the sound you hear is the boost converter trying to pump raw dc into the sub via shorted outputs.
many such converters will run at low freq under severe overload or a short.
replace the bad ones or all of them if you have them.start it without the speaker and disable bridging.
now measure for dc at each speaker.anything over milivolts is bad.often drivers go with the outputs.
i test everything from diff pair forward and then always run the dc test without speakers.
and dump those suscons.had a rockford-fosgate here with some in it and they were bad.
got one of those big chrome flames audiobahn amps here with all the caps in the converter blown.suscon.big mess inside it.

[Chris1992]

Re: JBL CS200.1 blows fuses on power up

@kc8 regarding the audiobahns: Thus proving Mike Chin's rule: any product with much bling, is just bling.

[tylerlough]

Re: JBL CS200.1 blows fuses on power up

Thanks a whole bunch for your replys
It never got wet so all that crap is from the factory.
The big caps are SD 105C, small dark blue are SL 85C, light blue SN 85C
It has less then 30 hours by me, but it is a refurbished unit.
Is it really nessarsary to replace the caps

[tylerlough]

Re: JBL CS200.1 blows fuses on power up

Thanks much for all your replys
K8: so what you're saying is the output stuff is shorted cause too much draw on the power supply then that blows the fuse.
Also could you or someone point out were the boost converter is. I think the boost is the two coils. I'm not shure the path the power takes and what is part of the power side or the output besides some or all of the tranistors
Where would I get all the transistors from.
for testing I will use this as a guide http://www.bcae1.com/ampfail.htm
could it also have failed resistors by the FETs

[kc8adu]

Re: JBL CS200.1 blows fuses on power up

power section is around the big toroid.
outputs have the white resistors next to each one.

[kc8adu]

Re: JBL CS200.1 blows fuses on power up

@kc8 regarding the audiobahns: Thus proving Mike Chin's rule: any product with much bling, is just bling.

the only thing these are missing as far as bling is those goofy $ wheel spinners.
strike that!might want to patent it and start making amps with them...motor driven of course!

[tylerlough]

Re: JBL CS200.1 blows fuses on power up

bling bling, and that's why I keep it under my seat.
I took a fet out and am checking it now
Damn thats what the white things are

[tylerlough]

Re: JBL CS200.1 blows fuses on power up

Ok I put two 15amp fuses, I measured .5volt dc when it is just plugged in and not on
Turned it on 2-3 volts DC came out speaker terminals.
I really don't think its the ricer type of amp

[japlytic]

Re: JBL CS200.1 blows fuses on power up

What are the values of the 7 large capacitors (SD series)? I want to cross-reference their paramaters with a good brand.

[tylerlough]

Re: JBL CS200.1 blows fuses on power up

big 4: 2200uf 63volt 22mm wide by 26mm tall
2: 2200uf 35volt 16mm wide by 21mm tall
1: 1000uf 35volt 14mm wide by 26mm tall
That one output side fet I tested seemed fine but I gota check more of them

[japlytic]

Re: JBL CS200.1 blows fuses on power up

A good replacement for the Su'scon SD series are Nichicon PW Series

The Su'scon SL series are general purpose units; use a good brand of high-temperature (105C or higher) units. Also, the Su'scon SN series are bipolar units; again, use a good brand of high-temperature (105C or higher) audio grade units.

[tylerlough]

Re: JBL CS200.1 blows fuses on power up

The caps jbl put in are a custom size because su-scon doesn't have that size on their web and it's a sub amp so sound quality is kind of a non issue for me.

[tylerlough]

Re: JBL CS200.1 blows fuses on power up

I didn't give up on it yet, I found that the middle TIP36C is shorted, it is the only one I could find.
I think I should replace all six output transistors because they only cost $1.74 a piece.
$10.50 to fix an amp, not too bad.
What would happen if turn it on with that TIP36C removed and no sub hooked up, could it damage something. It would be for only 3 sec or less.
I just want to test it without that tip36c in, to see if that is the only problem.
Also, what cleaner should I use to clean that dried white crap off the bottom of the board.

[kc8adu]

Re: JBL CS200.1 blows fuses on power up

pull and replace them all.i often pull outputs and run to determine if other problems exist that would kill new ones.most cases drivers,bias diodes,emitter reistors,ect die along with the outputs.

[tylerlough]

Re: JBL CS200.1 blows fuses on power up

how would I Know if something else is wrong
What would happen if I just removed that shorted output.
I think you're going to say it's bad, don't do it.

[tylerlough]

Re: JBL CS200.1 blows fuses on power up

Sweet It works with out that one tip36c
I hooked it up to a small speaker and a 12v battery with a light bulb as a resistor to limit possible damage. It sounded fine other than it was all below 320Hz. One thing I did notice was the heat/case was made in 2001 so that's at least 4.5yrs. old
to the repair man
to TC and KC8 helping me also to japlytic.
I'll tell you how it turns out in about a week

[tylerlough]

Re: JBL CS200.1 blows fuses on power up

Well I really don't think that I'll be able to fix it my self but I can try.

I finally got the parts and fixed it my self with your help.
Thanks guys