Matrix GT1000FX 1u Powering Off

Morbid

Morbid

Inspired
I've had this GT1000FX for over a year now and haven't had a problem. I haven't changed the way it's connected or setup since I got it and it's operated flawlessly up until today.

Today I was playing, and suddenly had no sound at all. No clicks, no pops, no thin sounds, no drop in volume, just gone. Lights were off (inside and out), and when I turned it off and turned it back on, nothing changed...it was like the poweramp was unplugged.
Unplugged it, turned everything off, relocated the plug, tried again, nothing. Turned everything off (including the Furman), and one of the lights on the inside came back on on the inside, and the poweramp "clicked", even though the Furman was powered off. Tried to turn the amp back on, and it was fine...sounded normal. Played for about 5 minutes and it died again.
The Protect light wasn't on, the only thing odd is that one of the orange LEDs on the inside on the right side is flickering, but I assume those are just for pretty.

I hit the manual and couldn't find anything helpful. Took the top off, everything looks fine, the fans are clean (and working), nothing smells burned, nothing is visibly wrong, none of the caps are popped or protruding. I wanted to check the fuse, but it's stark white...can't see the filament inside it.

Since it's the weekend, I can't call the company, so I was hoping maybe someone here had an idea.
 
I would replace the fuse even if it does not look blown. I believe mine came with an extra one but I've never used it.
 
I don't have an extra on hand I'm afraid, so I'll have to figure out exactly what it takes.
I'd love it if it's the fuse, but like I said, it's not a see through fuse for some reason, it's just straight white. Never even seen a fuse like that.
So blown or not I'll have no way of knowing until I do replace it I guess.
 
I am no tech but I think the white fuse you see is made to withstand a little surge or heat before it blows some call them slow blow. I would not think though if the fuse had blown that the amp would have powered back up, but it cant hurt to try one just for good measure.
 
I did some looking up and discovered it's a ceramic fuse, thus the white.
Paranoid; I'm inclined to agree with you, so just in case I did a quick check with a multimeter. Fuse seems to be just fine.
Not saying I won't replace it when I can (I'll have to order online), but in the meantime, anyone else have any suggestions/experience with a similar issue?
 
Morbid said:
I don't have an extra on hand I'm afraid, so I'll have to figure out exactly what it takes.
I'd love it if it's the fuse, but like I said, it's not a see through fuse for some reason, it's just straight white. Never even seen a fuse like that.
So blown or not I'll have no way of knowing until I do replace it I guess.
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Look on the back panel. doesn't is say; (230v-6A) or (110v-12A)
 

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Well, just got off the phone with the company.
They had no suggestions or thoughts, just want me to send it in for repair.
Anyone else have any suggestions other than the fuse before I go this route?
 
It could be one of a number of things which is probably why Andy (if you spoke to him) didn't give a definitive answer. If the fuse had gone the amp would not have powered up at all.It could possibly be one of the supply rails dropping voltage (less than the recommended voltage) so the amp doesn't have enough power to work. Repair is the best option and the guys will get it turned around quick enough and get you back up and making some noise.
 
Hey Lightning,

Don't believe I spoke with Andy...I'm generally pretty good at remembering the name of who I spoke to, but I don't recall one ever being stated. Later in the evening I sent an email, but received a very similar reply, which left me a little disheartened. This is honestly the first time I've had an issue with a piece of guitar equipment, and didn't at least receive a suggestion or opinion about what the problem could be, before shipping it out.

However, I did receive a second email today from someone else (Robin), with a suggestion. "The problem will most likely be a small, 7-pin chip located at the rear left hand corner. I cannot guarantee that is the fault, but from your description it is highly likely."
I found the chip, and it's a relatively cheap purchase. Fortunately, I have a friend who is gifted when it comes to electronics, and I'm going to have him take a look and possibly replace the chip and hope that's the problem. If it turns out to be the chip, it'll save me roughly $60 in shipping, which is considerable right now. While I'd love nothing more than to be able to shell out the cash for shipping, right now the timing is just poor.
 
For anyone interested. I had the chip replaced, and the amp seems to be just fine now.
A simple $5 chip and some soldering skill saved the day.

Should anyone else find themselves with a similar problem, the chip can be purchased here: TOP242PN Power Integrations | 596-1066-5-ND | DigiKey
Shipping is fast and the price seems fair.

As per the email suggestion I received from Robin at the company;
"Do not remove the board from the chassis, simply cut the legs off the chip as close to the chip as possible, remove the chip body and then heat the joints as close to the board as possible, use pliers or tweezers to pull the legs free of the board from the top side.


When fitting the new chip, do not try to push the legs back down the holes, it is difficult and time consuming. Simply cut the legs on the chip short and place it on top of the board, solder the chip to the pads on top side of the board. Inspect for solder bridges between the pins, note that several of the pins are on a common earth plane, so solder bridges here are not a problem as the pins are joined together anyway.


Using this technique it is possible to replace the chip in under 10 minutes and you don't need to remove the PCB from the case."
 
Hey Morbid,
Thank you very much for your May 2015 info. My 6 year old Matrix GT1000FX behaved exactly the way you described some days ago. After replacing the TOP242PN everythings works well again, so I thought it would be no bad idea pointing to the info you shared.
 
Hey Earnie! I'm glad this thread was of aid to you! Mine is still going strong since the replacement. It's a fantastic amp :)
 
My gt800fx blew a couple of months ago, it went into protection mode then somehow blew the speakers in the cabs. I got the same response, send it to the UK or US, I bought it used and it will cost me the same amount to ship it round trip as I paid for it. So for now it sits as a paper weight.

Cheers
Anthony
 
Morbid said:
Hey Earnie! I'm glad this thread was of aid to you! Mine is still going strong since the replacement. It's a fantastic amp :)
Click to expand...
Morbid said:
Hey Earnie! I'm glad this thread was of aid to you! Mine is still going strong since the replacement. It's a fantastic amp :)
Click to expand...
Yes, it's the best sounding amp for the Axe-Fx IMO because they use fast mosfet power transistors and not a bipolar or digital power section. I put in a high quality chip socket after removing the faulty chip first so the soldering job is done already, should this happen again.
Cheers
 
Anthony76 said:
My gt800fx blew a couple of months ago, it went into protection mode then somehow blew the speakers in the cabs. I got the same response, send it to the UK or US, I bought it used and it will cost me the same amount to ship it round trip as I paid for it. So for now it sits as a paper weight.

Cheers
Anthony
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I regret your situation. Blown speakers and a constantly lasting protection mode usually indicate a much more serious fault.
Cheers
 
Anthony76 said:
My gt800fx blew a couple of months ago, it went into protection mode then somehow blew the speakers in the cabs. I got the same response, send it to the UK or US, I bought it used and it will cost me the same amount to ship it round trip as I paid for it. So for now it sits as a paper weight.

Cheers
Anthony
Click to expand...

Yes it definitely isn't related to the Topswitch issues mentioned in this thread. No quick fix if it is in protect mode I'm afraid and generally we like to repair the amp ourselves. Most guitar amp techs don't have a good knowledge of SMPS amps so usually the ones we've seen "attempted" to be repaired require a lot more work. Usually works out cheaper and quicker in the long run to send to us and have repaired.
 
My Matrix turned itself off (protection mode) last night at rehearsal. After a minute or so, it would switch back on OK, but again, after another minute it went off again. This kept happening. Then I tried powering it on with the speaker leads unplugged, and then it stayed on OK.
So I'm wondering, could a bad speaker lead be the thing that causes the Matrix to shut down?
Curiously, I set everything up again at home today, using the same speaker leads, and there is no issue at all. Possible intermittent cable fault??
 
I had this exact issue happen to me over the weekend. In fact, I logged into the forum just now to search for this very issue! I've just placed an order for that chip and will have my tech replace it. Thank you for the information. I too love the Matrix amp. It has worked flawlessly for me for many years.

I will say it was a bit of a treat to run through practice just going straight into my old Marshall amp! haha!! No effects to get in the way, no nothing. Just pure guitar into amp into 4x12. Sometimes it is good to go "simple" and just rock!!
 
Earnie_R really like the socket idea. My 1000 did this some months back at a gig. I shelved it and used another amp for a couple months before even trying the matrix again. the matrix turned out to be fine and have been using it since, I think there was a low voltage issue at the club. I have since started using a battery backup power conditioner. I plan to order a few of these and a socket or two for when the time comes.
 
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