Jump to content
Welcome Guest!

Join us now to get access to all our features. Once registered and logged in, you will be able to create topics, post replies to existing threads, give reputation to your fellow members, get your own private messenger, and so, so much more. It's also quick and totally free, so what are you waiting for?

Sign in to follow this  
freezy

Blew up my Creative Gigaworks T3 Amp - or not?

Recommended Posts

Hi folks,

before completely hijacking the other thread, I thought I'd post the follow-up in a separate one. Many thanks already to maxx and zebulon who helped me out a lot!

For the history, my main power switch seemed to have produced an over current which blew out the fuse of my amp:

IMG_20130205_113427.jpg

Since I didn't have such small fuses and I certainly didn't feel like soldering a new fuse every time it blows, I've soldered two wires to an external fuse holder and screwed it into the amp:

attachment.php?attachmentid=23821&d=1360068552

The fuse that was blown says T1AL250V which I suppose stands for 1A slow blowing at 250V. So I've ordered some of those, but when I plug the amp, it blows instantly.

Now zebulon mentioned that the resistors may be damaged as well. I tried to take a better photo:

IMG_3357_zpsd6e66a08.jpg

Could that be the reason the fuse blows? And if so, can anyone decrypt which kind of resistor those are so I can replace them?

Thanks in advance, guys.

Share this post


Link to post
Share on other sites

As you can probably tell freezy, that resistor has been cooked! Looks like a 100 ohm resistor if I am right with the colors of brown, black, brown. Might be something further upstream that caused the resistor to blow.

Cheap fix if it is just the resistor and fuse....

What do you reckon Zeb?? Do you think that might be the resistor for the transistor shown in the first shot?? The gate might be cooked? (thinking outloud here)

Share this post


Link to post
Share on other sites

Thanks for the feedback, guys. Firstly I was confused by the silver ring, but when looking closely that's the resistor behind the plastic layer, which was originally indeed brown / black / brown / gold, which stands indeed for 100ohm.

The gold ring means +-5% tolerance, right?

I found this, however it says only 1% tolerance. Is that a problem?

Share this post


Link to post
Share on other sites

Yup, swap out that resistor and the other one (R30, probably a similar value). As well, replace Q1 (the transistor). It's going to be something along the lines of a 2n3906 or 2n3904 (depending on how they ran the circuit, tough to see). I'd also look for a diode somewhere that has blown. If all that fails, I'd bet the transformer is cooked.

Gold bands are 5%, silver are 10% (I believe, would have to double check). I wouldn't worry about the tolerances for now. Get it working first and then fine tune if necessary.

Share this post


Link to post
Share on other sites

Thanks, Zeb!

The other resistor also looks like 100 Ohms:

IMG_3314_zps2f07bb20.jpg

So the tolerance doesn't affect the functionality?

Do you need an image from a different angle in order to determine which transistor is used? Also I have no idea how to solder the transistor, this one looks quite different than the one on the board.

Share this post


Link to post
Share on other sites

tolerance does effect functionality! but getting a smaller tolerance resistor then your current one is ok :)

high tolerance ones like 0.5% and 1% r normally used in adc's and other high accuracy systems low tolerance are normally used for pull up/down resistors or for leds or somin, basically where you really dont care if its exactly the value its ment to be.

Share this post


Link to post
Share on other sites

By the way, are you guys sure the C7 in the middle is a transistor? Don't those come with three terminals? I have only two there:

IMG_3360_zps4934b3ee.jpg

On the back, it looks like this:

IMG_3362_zps076813b6.jpg

Edited by freezy

Share this post


Link to post
Share on other sites

Oh right, I overread zebulon's remark about Q1. Are transistors usually labeled? Should I scratch off the yellow stuff that is glued on top and see if I can get more info about which transistor it is exactly?

Share this post


Link to post
Share on other sites

LMAO...you know, I just realized what we're going through all of this for.

Freezy, do you know what the voltage output of this power supply was? You could most likely just replace it with a wall wart and be back up and running. It's most likely that it was in the 12v-18v range.

Share this post


Link to post
Share on other sites

Yeah that's what I thought too at the beginning, but the PCB where the PSU seems to be is the same where all the inputs and outputs are soldered onto. Then a bus goes up to the other board where the amp and whatever is. Not sure how I would just replace the power unit...

Share this post


Link to post
Share on other sites

Offhand I'd say that the red and black wires coming off the board are your power feeds for the amp. If you ran a ground to the black and left it connected to the circuit board and disconnected the red from the board and connected it to a power supply you would be bypassing the onboard power supply. If you could get the amp powered up that way, I'd just remove the transformer and burnt components from the board to eliminate any possible interference/feedback of voltage and connect the power supply to those wires and plug the red back into the board.

Basically, you strip the old supply hardware out of the board and connect at the output terminals of the old amp. As long as everything else is removed, there's nothing left to short to.

Share this post


Link to post
Share on other sites

To be honest I don't feel too confident about this solution. Normally if pros like you guys start guessing I'm already completely lost. ;) Additionally I don't have any of those components lying around, so every time something burns I need to order it somewhere with shipping costs and delays involved.

So my current plan is to find the right transistor, replace the two resistors and the transistor, and if that doesn't work throw the whole crap out of the window and buy a new one. Therefore, suggestions about which transistor to find would be very appreciated :)

Share this post


Link to post
Share on other sites

Resistors finally arrived. However they look completely symmetrical. Is the orientation important at all when soldering into the PCB?

Edited by freezy

Share this post


Link to post
Share on other sites

Seems not. ;)

However, the fuse still blows as soon as I plug the amp. Any idea why? Could it be my amateur soldering of the fuse? Or could a broken transistor be the cause of that?

EDIT: This is how it looks now:

IMG_3380_zpsf0192cf3.jpg

IMG_3382_zpse221e601.jpg

Edited by freezy

Share this post


Link to post
Share on other sites

Hmm I've just noticed that my replacement fuse (left) says T1L250V while the original (right) reads T1AL250V. Maybe that's the problem? Doesn't the "A" just stand for ampere?

IMG_3383_zps0ff60c8f.jpg

Share this post


Link to post
Share on other sites

Well, the original fuse was a slow blow fuse, as long as the replacement is a 1A fuse there really is no difference based on the surge that the burning shows is happening.

That transistor is definitely gone but I'd be willing to bet the problem goes much deeper than that.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×