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Non ADA Gear => Rack Gear => Topic started by: rnolan on February 13, 2017, 03:26:00 AM

Title: GMaj2 blown fuse
Post by: rnolan on February 13, 2017, 03:26:00 AM
Hey ADAers, Mikes GMaj2 has blown the fuse in its power supply, we pulled it (the fuse) out on Sunday at rehearsal  :facepalm: (crap TCs' are difficult to open up  :dunno: , you have to take off the jack mounting nuts... and have all the special screwdriver bits (ahh but I have a few of them  :whoohoo!: who said buying tools was stupid.. )), then he used my (MP-2) guitar rig  >:D , so it didn't spoil they afternoon... (I think Mike likes the MP-2 triggered Wah.. LoL).  So he put a new fuse in today, blew straight away  :facepalm: crap.... He's looking into sending it to the TC tech support in Sydney (it's well out of warranty so this could be expensive, IF they even know what they are doing.. I suspect they'll just farm it out  :dunno: , I could be wrong).
Anyway, any ideas guys ??
So it's where the jug (IEC) lead comes into the unit, there's a small transformer and circuit board, the blown fuse is next to the transformer.
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on February 13, 2017, 03:53:34 AM
Does it have a switching PSU?
Title: Re: GMaj2 blown fuse
Post by: Iperfungus on February 13, 2017, 03:55:25 AM
No...these units have internal power supply.

Looks like a short circuit somewhere...transformer maybe?
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on February 13, 2017, 04:00:07 AM
Ok but it still can be a switching PSU,does it work on a wide range of input voltages?
Title: Re: GMaj2 blown fuse
Post by: Iperfungus on February 13, 2017, 04:07:52 AM
Ok but it still can be a switching PSU,does it work on a wide range of input voltages?

Yes, you're right MJMP.
100-240 VAC - 50-60 Hz 15W
Title: Re: GMaj2 blown fuse
Post by: rnolan on February 13, 2017, 06:46:20 AM
Hey MJMP, yes is switching PSU, just plug in a jug (IEC) lead it does the rest no matter what country/power supply (ish). Could it be a diode (gone) in the rectifier circuit ? Apart from the fuse all else looks ok  :dunno: .
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on February 13, 2017, 07:03:13 AM
Could be you can always check them out if your meter has a diode check.
Title: Re: GMaj2 blown fuse
Post by: rnolan on February 13, 2017, 07:17:21 AM
Hey MJMP, I'm pretty sure it does have a diode check, will give that a go, anything else it might be ?  We were running off a generator the last time it worked..
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on February 13, 2017, 02:22:35 PM
Could also be one of the switching transistors or mosfet's that stays on (busted) which also results in a blown fuse.

Is it a separate pcb (the PSU)? Sometimes these are off the shelf PSU they stick in there for easy repair. I repaired an axefx once that way, just bought a new one from mouser and it was fixed. If not sure, take a pic.
Title: Re: GMaj2 blown fuse
Post by: MikeB on February 15, 2017, 02:08:58 AM
Yep, it's a separate pcb.   It would be great if I could do an easy fix because the agent wants $50 plus return postage just to look at it. attaching pics. Please let me know if you need more detail of close ups.
Thanks,
Mike

Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on February 18, 2017, 09:37:25 AM
Sorry Mike, seems I missed your post.I had a look around and can't find it for sale at mouser or farnell. It seems TC sells them for around 85 AU$ so maybe you can order one from them.You need a JKS020Q1.

I did found the schematic of it in case you want to poke around yourself.

http://www.dirk-hendrik.com/temp/TC_electronic_SMPS%20JKS020Q1.pdf

I also found it here  http://www.fullcompass.com/prod/099092-TC-Electronic-7E50000101

Title: Re: GMaj2 blown fuse
Post by: MikeB on February 18, 2017, 02:45:31 PM
No worries. I know you have a pretty full dance card.   Thanks for the links. I'll have to see what the shipped price is on this and then compare it with how much beer it will cost me to get my electronic engineer mate to have a go at the blown one.
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on February 18, 2017, 04:34:38 PM
Ok let me know if I can help out with something.
Title: Re: GMaj2 blown fuse
Post by: MikeB on March 03, 2017, 10:43:35 PM
So,
My mate, Glenn, has come around and had a poke around.  He found that one of the MOSFETs had blown (Q2 on the schematic).
The part number listed on the schematic is 2SK2526 or 2SK1637.  Mouser had an equivalent part (searching for 2SK1637) with a manufacturers part number of STF3N62K3.
They had this part listed at $1.87 Australian but with $24 postage.  Then I had another poke around online and found through RS Online the same part that I can get delivered for $4.88 (for a pack of 5).
I'd be grateful if you could confirm that these two parts are interchangeable (see attached datasheets).  I have ordered it in any case as the gamble of $4.88 is one that I'm prepared to take.
Glenn also found that the D9 diode was blown.  The schematic just lists this part as "small signal silicon with 0.6VTH".  I have bought a packet of 5 diodes (for 80c) that are labelled as "1N914/1N4148/BAW76 D035".  Will one of these do the trick?

I do appreciate any input you can give me on this.  Thanks.

Cheerio,
Mike
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on March 04, 2017, 07:30:27 AM
From what I can tell they look good, they even have a bit more power. (45Wvs 35W)

A 1N4148 is a small signal diode, so should do the trick. Let's hope nothing else is busted that could have caused the Q2 to blow up itself.
Title: Re: GMaj2 blown fuse
Post by: MikeB on March 04, 2017, 11:38:31 AM
That's good news. Hopefully the part will arrive this week and I can get it back together next weekend. I'll let you know how it goes. Glenn is pretty sure that everything will else was ok.  What sort of thing might cause the Q2 to blow? Dirty power from the generator?
Thanks for your help.  :waving-banana-smiley-emoticon
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on March 04, 2017, 02:33:21 PM
Hard to tell.
Title: Re: GMaj2 blown fuse
Post by: MikeB on March 13, 2017, 12:49:26 PM
So,  from $50 plus shipping just to get it looked at to $80 for a new power supply and then in the end spend only $6 on a MOSFET and a diode. Not a bad result. The g-major2 is back in business. Many thanks for your help.  :banana-guitar:
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on March 13, 2017, 01:59:41 PM
great ,let's hope it stays running, sometimes with these PSU's there more too it and sometimes not.If it stays running after a week you'll be fine.
Title: Re: GMaj2 blown fuse
Post by: rnolan on March 18, 2017, 04:36:32 AM
All good, sounded great last night  :whoohoo!: didn't bat an eyelid.
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on March 18, 2017, 02:30:14 PM
Ok then it will keep running I guess.
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on June 30, 2017, 03:35:23 PM
The other guitar player in my band also has a G major with a blown PSU. Also blew up the fet but also a cap.
Title: Re: GMaj2 blown fuse
Post by: MikeB on June 30, 2017, 04:00:28 PM
Well, if it's a design flaw then I'm glad I had to buy six of everything.
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on July 01, 2017, 04:14:38 AM
From what I can tell the blown cap was the reason the MOSFET blew up. I saw a small crack on the outside of the cap, so I checked it with my LCR meter and it was busted.
Title: Re: GMaj2 blown fuse
Post by: Iperfungus on July 01, 2017, 08:16:20 AM
If it's a design flaw, I hope it's related to GMaj2 only....since I've the older GMaj...  :lol: :lol: :lol:
Title: Re: GMaj2 blown fuse
Post by: Iperfungus on July 01, 2017, 08:17:22 AM
The other guitar player in my band also has a G major with a blown PSU. Also blew up the fet but also a cap.

Being your friend, he's a very lucky asshole.  :lol: :lol: :lol:
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on July 01, 2017, 04:48:00 PM
If it's a design flaw, I hope it's related to GMaj2 only....since I've the older GMaj...  :lol: :lol: :lol:

It was the older G major  >:D  Seems to be a common problem. Anyway I'm waiting for the parts to come in but he already bought another G major.So when it's fixed he will use it for his home rig.
Title: Re: GMaj2 blown fuse
Post by: rnolan on July 03, 2017, 02:49:18 AM
Does that mean it becomes a GMinor  :dunno: :lol:
Title: Re: GMaj2 blown fuse
Post by: Iperfungus on July 03, 2017, 02:50:11 AM
Does that mean it becomes a GMinor  :dunno: :lol:

 :lol: :lol: :lol:
Title: Re: GMaj2 blown fuse
Post by: MarshallJMP on July 03, 2017, 10:37:57 AM
Does that mean it becomes a GMinor  :dunno: :lol:

Hahahahahahaha :thumb-up:
Title: Re: GMaj2 blown fuse
Post by: Harley Hexxe on July 03, 2017, 03:49:29 PM
I believe that's when you call it a G Flat.
Title: Re: GMaj2 blown fuse
Post by: Iperfungus on July 03, 2017, 03:57:05 PM
I believe that's when you call it a G Flat.

Or G sharp...  :lol:
Title: Re: GMaj2 blown fuse
Post by: rnolan on July 04, 2017, 12:14:36 AM
Lookout, we'll invent a new programming language... :nono:
Title: Re: GMaj2 blown fuse
Post by: Iperfungus on July 04, 2017, 12:32:15 PM
Lookout, we'll invent a new programming language... :nono:

Naaaaaaaaaaaaaaa.....ADA language has been invented already....  :lol:
Title: Re: GMaj2 blown fuse
Post by: Harley Hexxe on July 04, 2017, 03:37:19 PM
Lookout, we'll invent a new programming language... :nono:

Naaaaaaaaaaaaaaa.....ADA language has been invented already....  :lol:

We're inventing one for TC Electronic ;D
Title: Re: GMaj2 blown fuse
Post by: Iperfungus on July 04, 2017, 04:13:38 PM
Lookout, we'll invent a new programming language... :nono:

Naaaaaaaaaaaaaaa.....ADA language has been invented already....  :lol:

We're inventing one for TC Electronic ;D

Full of dirty words...ehm...statements...  :lol: :lol: :lol: