What is this that has blown?

[mikay786]

Re: What is this that has blown?

So the 50v are the correct value?

[budm]

Re: What is this that has blown?

I would have use 100V rating minimum. The caps are exposed to about 78 peak Voltage.

[ReeceyBurger123]

Re: What is this that has blown?

Probably best to use 100v one to limit damage in future cases mate.

[mikay786]

Re: What is this that has blown?

Alright I'll order some 100v

Can I use the ones installed for testing purposes as wont get replacements till Monday

And we're the original ones 50v?

[budm]

Re: What is this that has blown?

You can leave them out for testing purpose. The cap are there for to reduce Diode switching noise.

[mikay786]

Re: What is this that has blown?

Ok Maplins only have 2 100v 0.1uf caps !!

As I need four can I use higher voltage ones? Say 125v or 150v and mix and match?

[budm]

Re: What is this that has blown?

>100V will be fine.

GALE 3080.

[fzabkar]

Re: What is this that has blown?

BTW, what is the P/N of the power amplifier IC?

TDA7294

https://cdn.badcaps-static.com/pdfs/...6e7c926434.pdf

I can't see how +/-39VDC is reduced to +/-11V. ???

[budm]

Re: What is this that has blown?

'I can't see how +/-39VDC is reduced to +/-11V. ???'
The 2SC1815 & 2SA1015 and the Zeners are for the linear regulators.

[fzabkar]

Re: What is this that has blown?

The 2SA1015 and 2SC1815 are rated for 50V, 150mA, 400mW:

(2SC1815)
(2SA1015)

A voltage drop of 28V (= 39 - 11) at 15mA would exceed the power rating. Does this mean that the other board is only drawing around 10mA at +/-11V? The power LED must be drawing at least 5mA.

[mikay786]

Re: What is this that has blown?

Went to maplins again and they only had 3x 150v and 1x 180v capacitors.

Will these be ok?

And just googling the numbers on them I'm not sure they are the correct ones

151j + 181j

He was saying all there parts draws are a mess as workers keep putting stuff back in the wrong place.

Also picked up some new fuse holders as per stj's recommendation

[fzabkar]

Re: What is this that has blown?

Those are not voltage ratings.

151J = 150pF
181J = 180pF

Neither capacitor is suitable.

[mikay786]

Re: What is this that has blown?

wtf maplins are bloody useless, I told him 0.1uf

[mikay786]

Re: What is this that has blown?

Are you sure I need 100v, I cant seem to find any on ebay or farnel in ceramic disk

[stj]

Re: What is this that has blown?

you dont need disc, you can use multilayer - little square ones.
as long as they are ceramic 100nf (0.1uf) at 100v minimum

maplin has been a waste of space for years btw.
farnell has free delivery with no minimum order these days - so use farnell.

[mikay786]

Re: What is this that has blown?

what about film ones?

yea maplins is open late and is down the road, plus weekend was coming up so earliest I would get from farnel would be Monday.

Truly dislike maplins!

[budm]

Re: What is this that has blown?

The 2SA1015 and 2SC1815 are rated for 50V, 150mA, 400mW:

(2SC1815)
(2SA1015)

A voltage drop of 28V (= 39 - 11) at 15mA would exceed the power rating. Does this mean that the other board is only drawing around 10mA at +/-11V? The power LED must be drawing at least 5mA.

If you look at the board, there are two 470 Ohms 1W resistors, each one for feeding the Collectors of the Transistors, the Zeners are probably 12V, so they are not feeding the transistors directly with 39V.

[stj]

Re: What is this that has blown?

here you go:
http://uk.farnell.com/vishay-bc-comp...rad/dp/1141783

[stj]

Re: What is this that has blown?

Truly dislike maplins!

i had to school the counter staff once over how to read the colour-codes on the resistors.
they didnt know the colours actually meant anything!!!!!!!!

[mikay786]

Re: What is this that has blown?

http://uk.farnell.com/multicomp/mcrr...rad/dp/1216434

Are these ok to use?