K8060 Blows fuse every time

Kits Audio Hi Fi Projects
1

Every time i connect to the mains using the toroidal transformer
(N04BA 2 x 30V 160VA 2 x 2.66A 115 x 42mm)
available from maplins.co.uk. it blows the inline 1A fuse.
Please advise as all connections are good.

2

Make sure that the transformer is correctly connected, especially if the colours of transformer wires do not match with the colours described in the manual. Check the diodes and the power transistors.

3

Thank you

But still no joy.
My transformer is from maplins and is described below
N04BA 2 x 30V 160VA 2 x 2.66A 115 x 42mmv

Is a 1A fuse too small???

Will putting a larger fuse in risk the chance of blowing the amp??
Or is it ok to just put the transformer straight into the amp??

Please help me.

Thank You

4

Did you check the diodes and the power transistors ?
What is the colour code of your transformer.
In order to be able to give hints, you will need to supply more information.
Did you use a 1A slow blow fuse (T) ?

5

[quote=“VEL417”]Did you check the diodes and the power transistors ?
What is the colour code of your transformer.
In order to be able to give hints, you will need to supply more information.
Did you use a 1A slow blow fuse (T) ?[/quote]

By checking the diodes and transistors do you mean the connections and polarities? because all this is ok.

Yes it is a 1A slow blow fuse.

Will it harm anything by just connecting the transformer to the mains without the fuse?

Also can i just put a fuse in line from the transformer to the amp instead of to the mains supply?

Also what does the (T) mean when describing the fuse??

Also the transformer shows it is for 230V ac
and the outputs are 1: 30V Red-Yel 2,66A
2: 30V Blu-Gre 2,66A

Is the fuse simply too small???

Thank You for being patient with me on this.

6

You’ve checked the polarity and connections of the diodes and the power transistors but apparantly you did not check them if they are defective or not. I have the impression that you are a novice. That is fine, but maybe it might be necessary to seek local help if you are unsure. You need a multimeter to check the power transistors and diodes, in order to see if they are internally shorted. If one or more transistors proves defective, I’d recommend to replace all transistors on the board.
Do NOT put a fuse between the transformer and the amp.
Furthermore, I would not test without a fuse. If there is a problem with the amp, it is very likely that you will destroy and burn the board.
The fuse rating is fine. (T) means ‘time-lag’ (=slow blow)

7

Instead of a fuse, use a 60W light bulb like described in the manual.
This is the only way to check if something is wrong with the amplifier or your wiring.

8

[quote=“VEL436”]Instead of a fuse, use a 60W light bulb like described in the manual.
This is the only way to check if something is wrong with the amplifier or your wiring.[/quote]

WOO HOOO

Thank you for your help but i have discovered it was the transformer giving me all the hassle.

Its typical that out of the 4 transformers i bought i picked the faulty one first.

No worries maplins has already ordered me a new one.

Cheers

9

OMG :frowning: i have the same problem my fuse blew im sure the amplifier is fine because i was running it off a pc power supply until yesterday when my N04BA Transformer arived from maplin i dont know whats wrong im not sure if i’ve connected the transformer right

(capasitor)…(1)…(2)…(capasitor)
(bottem of board)…(3)(4)…(bottem of board)

This is how ive connected it (#) are the terminals;
(1)Red
(2)Yellow
(3)Green
(4)Blue

Is this correct?

I have made sure of all my connections and im about to try it again in a little while i have some 1.25A (T) fuses im about to use i’ll see how it goes.

10

loooooooooooooooooool never mind got it to work turned out the fuse was jus dammaged and that little bit of power caused it to blow the 1.25A fuse seems fine im not sue about my heat sinks though i might have to look into it the ones i have are aout 5cm by 2cm by 3cm fins each for the 2 power transistors.

11

These heatsinks will be too small for medium to high listening levels.
Please check the dimensions of the dedicated heatsink on www.velleman.be