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Crown XTI 2000/4000

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#1 CCARMINATI

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Posted 01 March 2013 - 08:45 PM

Hi, I have issues with 5 diferent XTI amps. Before someone asks, amps have been tested outside the rack without any contact with the other amps. The issues I will describe are intermitent and present on some of the amps from time to time or sometimes at all amps at the same time:
1)Amps starts up just fine, but a second before the green light should turn green it turns off (relay clicks before going off).

2)After pressing the power button, the amps screens and input signal leds blink a couple of times like the amp was 'trying to start'; sometimes they do start, other times they shutdown.

As mentioned, it has happened with all, some or none of the amps at any given day.

#2 joust

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Posted 04 March 2013 - 11:08 AM

For part 1): My thinking is that there may be an output failure, possibly with the Cequel Tracker fets. It 'feels' like the VCC rails are not equal. The Tracker module permits the amplifier to switch between two rail levels, like on the MA5K series.

For part 2), it may be the bootstrap (KSTART) cap, it may be out of tolerance. You'll have to troubleshoot a little more when the amp is down.

Hope this helps!

Alain

#3 CCARMINATI

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Posted 11 March 2013 - 08:54 PM

Thanks Alain, but you really think that it is possible that I have the same issue with 5 diferent amplifiers?

#4 joust

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Posted 12 March 2013 - 07:46 AM

It is troublesome! I can't really say for sure, but it is possible. Though, what may all seem as same issue may not at all be related. The sample mode power supply (SMPS) behaves in much the same fashion when an outside fault is detected; Many different detected faults just stops the SMPS from driving on.
You may have to wait until the amp(s) break down before delving further in. Also, get in contact with your local Crown authorized dealer or service center.

(Did you implement the latest firmware updates?)

Alain

#5 CCARMINATI

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Posted 12 March 2013 - 08:30 PM

I believe that I am running the latest firmware (1.1.5.6). One thing that I noticed is that the issues wont appear as much on good power scenarios (Like on large and well prepared clubs or when running on a generator). I was able to cause a failed startup (3 out of 5 tries) by connecting one of the amps to an ungrounded power cord (5 out 5 good startups at the same amp on grounded cord). Could a grounding issue be the problem? I also noticed that when the rack is not connected to a grounded AC, I can get a really nice shock by touching the amps. IS that ok?

#6 joust

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Posted 13 March 2013 - 11:11 AM

Latest version with SA3.40 mentions both the 1156 and 2032;

As for ungrounded equipment: PLEASE PLEASE make sure your [rack] system is properly grounded! If you can get shocks, there is now potential of lethal dosage! I have heard of musicians (guitar players) getting shocked through a faulty PA (mics were grounded to the wrong side of the AC supply) and dying on stage! Just beware!

And yes, it is now possible that the electric circuit may be involved in your faults! The grounding may not be an issue: the electrical wiring may be the issue! Of course, the grounding too. Why is the electrical system not grounded?

A possible problem is current starvation from the AC power supply: the SMPS needs at a minimum perhaps 90 to 100VAC of AC power supply voltage; If the outlet doesn't permit the power requirement for the amps then they will get starved out.

Hope this helps! :)

Alain

#7 CCARMINATI

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Posted 13 March 2013 - 09:40 PM

System is grounded. Removed ground just for testing/troubleshooting. Firmware 2032 for XTI amps?

#8 joust

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Posted 15 March 2013 - 09:37 AM

If you have a multimeter, you could verify the voltage when the amps fails; Before powering up the amp setup the multimeter as close as possible to the amp's power outlet. Make measurements before and after powering up. I still think it's a power distribution issue.

Version 2.0.3.2 is availble with SA3.4; It may have been made available for the '02 models, my bad.

A.

#9 danmars

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Posted 12 April 2013 - 05:35 PM

i have an xti 2000 made in 2006 that wont cummunicate with my pc .it turns on and off on its own when connected to pc. but system architech and band manager both will not detect the device.any thoughts

#10 joust

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Posted 15 April 2013 - 07:30 AM

Hello Danmars,

Take a look at the first entry, 'Firmware updates for older XTi amps', located as the first FAQ in the Forum lists. It has an executable to load older XTI firmware. Hope this works!

Hey Carminati, Did you get your grounding and electrical issues resolved?

Alain

#11 CCARMINATI

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Posted 03 June 2013 - 09:46 AM

Well, this issue continues to be a problem. 3 XTI 4000 and 1 XTI 2000 on the same rack and all connected to same AC. When power is 100% all amps work fine. If power is not great, lets assume an 9 out of 10 (voltage about at 112 instead of 120+), one of the 4000´s fails to start. It turns on but never completes start up , shutting off right before it should open the channels(turn green). The reason I am posting again is that I had two amps fixed and are no longer having power up issues. The problem was that the service center replaced main boards on both amps, which is very expensive compared to the current price of these amps, specially used ones. Does anyone out there know where in the amp I should look to get this fixed? I would imagine that the power supply is detecting voltage that is lower than the actual one... I really dont care If I do something that completely breaks the amp, as I will apparently have to replace the mother board again....

#12 joust

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Posted 03 June 2013 - 12:45 PM

Perhaps an odd question, but are all amps powered up at the same time? Like, with a master switch?
If so, what happens when you power up the amps one at a time?

#13 CCARMINATI

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Posted 03 June 2013 - 07:17 PM

Same issue no matter how many amps are powered.

#14 CCARMINATI

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Posted 03 June 2013 - 10:14 PM

I guess I will try to follow the "Kick start" routine and try to replace a couple of things...

Kick start
Once voltage is present on U14, switching begins. The clock frequency is determined by C69 and R367 and oscillates at approximately 250-260kHz. 180-degree phased clock signals are provided to U18 for generation of the low and high side gate drive waveforms on pin 7 and 5, respectively. The transistors Q26-Q30 serve to increase the current drive to the IGBTs Q28 and Q31.
Switching commences for the time allotted by the discharge of C196, or approximately 100mS. During this time period the IGBTs transfer energy from the primary bulk storage (C57-C60) and the AC line through the resonant tank (C68 & L3) to the transformer, T1. The energy is magnetically coupled to the secondary of the transformer and hence C43-C48.

Energy is also transferred back to C196 through D26. If the voltage at C196 is
maintained at a point greater then the lower bound for the Vkstart sense comparator, U16B, then the controller circuitry becomes sustained by the converter itself and the kick start cycle is terminated. If for any reason the converter does not sustain the voltage on C196, the kick start cycle will repeat indefinitely approximately every 500-800mS.


             I will try the easy to find first (C196, D26). It looks like C196 is the one 'deciding' if the amp finishes the startup sequence... I will measure voltage at C196, if its ok I will replace it.


#15 joust

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Posted 05 June 2013 - 09:09 AM

If an XTi doesn't start: First, determine if the BULK voltage (170VDC before relay enables) is present (TP30 in regards to TP21, BULKRET);
Then measure the voltage at R375 (coming from IC16 pin 1): Normal should be around 16V, because of the 16V Zener diode;
I sometimes remove R375 to confirm 16V Zener presence. Replace R375 for the next tests.
If 16VDC is not present, different signals should be present:
a) around 2VDC, and a short impulse every few seconds: Bootstrap cap (C196) charging and discharging: Cap is good;
B) around 1.6VDC and no impulse, straight, then Bootstrap cap is faulty, to be replaced;
c) around 0V, then the Fault circuit may be at fault, verify Q15 and Q7 in the Crowbar circuit.
Beware! High voltages present, and reference is on the BULKRTN (TP21)!
DO NOT GROUND BULKRTN,TP21! ALL EQUIPMENT GROUNDS SHOULD BE ISOLATED VS BULKRTN!

Hope this helps!

Alain





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