studiomaster vision 8

Hi all, I'm new to repairing electronics so I was wondering if some of you knowledgable folk could kindly help me?
I have been given a Studio master vision 8 amp/mixer for PA use.
I have opened it up and found what looks like a transistor called T3 on a board named R1A1-4.
I will attach a photograph of suspect component.
I used to be a telephone engineer so have used a soldering iron quite a lot.(mainly cable jointing)
Before I take the whole board out to renew this component is there any one out there who has dealt with this before?
If there is do I need to renew any other components whilst it is open on my bench?
Also where can I get this part, I'm living in Swansea Wales, UK.
..........Thanks for any help..........dylanthermos.

Why do you suspect this component?

And how have you determined the correct replacement -- the part appears to have no markings?

To replace this transistor, simply undo the bolt (or whatever) that is holding it down, then use some solder wick or a solder sucker to help remove the solder. Insert a new part, bolt it into place, and solder the leads.

There appears to be a hint of some slight discolouration of the board under the transistor, but this is not necessarily an indication that it has failed.

I suspect this component because the circuit board under this component is scorched.
This appears only here.My photograph is not that good but also it says TR3 printed on the board next to the part.I assumed this to be its name?
The black dome shaped button on the top of the transistor disintegrated when I tried to see if it was bolted down. I was a plastic/bakerlight material that just crumbled.
I also assumed that this was because it had endured too much heat.
I know nothing about doing this type of repair but am prepared to have a go, what have I got to lose this mixer desk is standing idle.
Where would I acquire this part? Would you kindly suggest a supplier?
Thanks for taking time to reply I really am grateful.......dylanthermos.
Please see extra pic below.......

Another angle of pic

There's nothing written on the device. It could be almost anything.

You need to find a service manual which may have more information.

OK, have a look here.

There is a schematic for a StudioMaster Powerhouse Vision 908. I don't know how closely these are related. If you are lucky they may hare similar circuitry and you may be able to find something useful here.

Check page 3. This looks like the fan control. That transistor would be a TIP30.

I can't see that a failure here would cause your symptoms. It may cause the unit to overheat though. Does the fan operate?

Hi Steve, I have'nt run the mixer amp for a while. Last time I did the power light came on but I don't remember a noise from a fan. Perhaps it won't start running till it gets up to a certain temperature?
I'll strip it down again and be very careful as to what I touch whilst it is open.
I'll use headphones so that it doesn't have to be connected to a pair of speakers.
I'll come back to you in a few days cos today is "She who must be obeyed's" birthday.
Speak soon........dylan.
So will probably be tomorrow or next day.

Well managed to power up the mixer amp but the led's did not light up.I could hear a power hum when I had the headphones but no fan sound, so next job will be to go to Maplins and get a transistor TIP30.
When that is in my possession I will let you know.
Then I can do the hard bit and replace it.........thanks will keep you informed.....dylan
Not saying that this will completely restore it to full service.......

There seem to be a couple of signals which turn on power to the fan. It is quite possible that neither of these is asserted and this is why the fan is off.

It may be a red (or in this case black) herring.