help troubleshooting XTANT 603x problem!

[pape]

My Xtant 603x recently stopped working. One second it was playing find at low volume and with no pops or anything, no more sound. Checking the amp it was still on (power led). It turns on and shuts off properly, just no sound.

So I opened her up, nothing is burnt. Here is the strange part. On the board there is test points for voltage: +-18v (reads about 20), +-25v (reads about 30), +-42v (reads 42), and the kicker the +-52v reads .5 volts .

I tried testing all the tranistors (8 STP60NE06-16) and rectifiers (4 and I don't remember the part #'s) on the power supply. They seemed ok, I also desoldered the rectifiers and tested them off board, they check out. I guess I can take the transistors off and test them, but 8 is a lot of them and the solder used on the board doesn't like to stick to my desoldering braid.
Any other ideas on possible problems or what I should look for?

Note: Some idiot had mounted it to MDF at one point in time and being as the mounting screws are under the cover and the screws he used didn't like MDF, a screw fell out and shorted out one channel. So he replaced all the transistors on that channel and everything worked fine for 4 months until this problem.

Thanks,
Lee

Sorry for the length.

 

[pape]

hmmm was wondering if this would be better off posted in the Amplifier : Solid State forums? or is this the right place.

 

[djQUAN]

if you have an oscilloscope, check out all the waveforms on the primary and secondary of the transformer.

 

[pape]

I do and will try that tonight.
It is a pain in the neck lugging it to my car all the time, hmm time to buy a 12v powersupply.

I was studying this: http://sound.westhost.com/project89.htm, to get a better understanding of an car amp power supply. It is a similar setup I think, except it seems to have 2 seperate supplies off of the one transformer. Each going to a bank of 4 STP60NE06-16. Learning little by little.

Thanks!

 

[djQUAN]

one more thing, you could do some retracing of the foil paths and see the components related to the output which dos not have any power going out and seeing which components are bad.

 

[Paradise_Ice]

Could you not just ask Xtant? email them and detail your problem, am sure they could help, but maybe they would just blow you off, I think you have checked alot but may have missed something, God know i have done that in the past, take your sweet time and just check everything, i suspect that the transformer may be goosed, oh you dont need a 12 volt power supply, just use a battery.

 

[pape]

yeah I played around more yesterday. One of the FETs (P60NE0) and one of the Rectifires (FEP16CT) were making a chirping sound, all others were silent. Not sure what that means.
Also I think the point labeled +-52v on the board must be +- 0.52 since that is what the meter reads exactly.

Anyways I ordered new rectifiers and transistors and will replace them next week.

Thanks for the help.

 

[pape]

Hmm just thought of somethings. Since there is absolutely 0 voltage at the speaker outputs, I am wondering if it is something with the turn on delay. What would a delay circuit look like? It would kind of make sense.

 

[pape]

I figured out where it is, it is using a TIP30C for switching I think. More looking when I get home from work. I will figure it out someday.

 

[Paradise_Ice]

How did your amp stop working? I dont know much about Xtant but they work on certain voltage ranges right? no less than 11.5 and no more than 16 v, I am trying to buy a X1001 so i can make a copy. i live in Scotland and its only for my own personal use,so dont worry about me ripping anyboy off. How do you rate your Xtant? am having second thoughts now, yours seems troublsome.

 

[pape]

well mine I bought refurbed and it was DOA. They repaired it for free (put a whole new board in).
The reason it is broken now is completely my fault. I mounted it to and MDF rack using screws and guess I stripped the wood. One fell out and landed on across the terminals on a FET.

I repaired that by replacing the them and now 3 months later, I started the car and it starte up just fine and about 10 seconds later no output. So I am assuming it is something from before that was about to go.

I know quite a few people that are happy with XTANT and their tech support is second to none. I would by another one, I am thinking about it now. Really nice people.

 

[pape]

Found it. Sure enough in the muting circuit there was a cap with a small rusty hole in it. It was open. I didn't have a chance to swap it out yesterdy but will do it in the next few days.

Thanks for the help!

 

[Stooo]

Where can you find output transistors and mosfets for this amp? Also are the SMT resistors 220 ohm or 22 ohm ... 1206 or 1205 in size? Mine powers on still but havent tried to play anything till I get the parts in.