What is this that has blown?

**mikay786** · 10-30-2015, 06:19 AM

Re: What is this that has blown?

Tested both transistors and they seem to check out ok c1815 & a1015

**mikay786** · 10-30-2015, 06:23 AM

Re: What is this that has blown?

Is it safe to just put in new fuses and test without the 0.1 uF caps (as have removed them (3 in a row))

**ReeceyBurger123** · 10-30-2015, 06:25 AM

Re: What is this that has blown?

Yeah you can remove them, and run with out them I have in the past. Let us know what happens.

**mikay786** · 10-30-2015, 08:49 AM

Re: What is this that has blown?

Had to go to maplins to get some fuses and they had a couple of them .1uf caps so bought too (Why is it they only have a couple of what ever you need ever)

So soldered everything back in, fuse holder legs on either side had corroded off so not holding fuses tightly so soldered the fuses in as best as I could on one end.

Powered up and seems to power up fine, green led. Switch off and switches off. Not got the speaker connected so will reassemble and get speaker hucked up.

I don't have a amp with a line out (well a working one anyway) can I just connect a normal music source via rca to it just for testing?

**ReeceyBurger123** · 10-30-2015, 08:55 AM

Re: What is this that has blown?

Nice one, also what Voltage were the caps you got ?

**budm** · 10-30-2015, 09:02 AM

Re: What is this that has blown?

Unless the unit has protection relay, I would check the DC Voltage at the speaker terminal first to make sure it does not have high offset Voltage just in case there is problem in the power amplifier sections that will damage the speakers.

**mikay786** · 10-30-2015, 09:10 AM

Re: What is this that has blown?

Originally posted by ReeceyBurger123

Nice one, also what Voltage were the caps you got ?

0.1uf

**mikay786** · 10-30-2015, 09:12 AM

Re: What is this that has blown?

Originally posted by budm

Unless the unit has protection relay, I would check the DC Voltage at the speaker terminal first to make sure it does not have high offset Voltage just in case there is problem in the power amplifier sections that will damage the speakers.

so just measure the voltage of the wire that connects to the speaker?

If so can I just measure it on the board connector pin out for speaker?

**ReeceyBurger123** · 10-30-2015, 09:19 AM

Re: What is this that has blown?

Originally posted by mikay786

0.1uf

No I meant voltage not capacitance ? Uf is capacitance btw.

**budm** · 10-30-2015, 09:21 AM

Re: What is this that has blown?

'so just measure the voltage of the wire that connects to the speaker?, If so can I just measure it on the board connector pin out for speaker?' Yes.
Can we see the pictures of the whole unit and the boards?

**SteveNielsen** · 10-30-2015, 09:21 AM

Re: What is this that has blown?

It's better to check at the output on the amp itself in case the speaker wire is damaged.

**stj** · 10-30-2015, 09:21 AM

Re: What is this that has blown?

should get 1kv or 2kv caps
and some fuse clips / holders.

**mikay786** · 10-30-2015, 09:28 AM

Re: What is this that has blown?

Barely measuring anything at the pins, like 0.001v

Is that good or bad?

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**mikay786** · 10-30-2015, 09:29 AM

Re: What is this that has blown?

Originally posted by ReeceyBurger123

No I meant voltage not capacitance ? Uf is capacitance btw.

50v according to the receipt

Crap totally forgot about that, not sure what the original ones were

**eccerr0r** · 10-30-2015, 09:46 AM

Re: What is this that has blown?

You know, I was pretexted by the initial photos that this was a switching supply. Now I am thinking this is probably a low voltage (or at least relatively low) supply made from a transformer, and 50V capacitors may be fine...

As I thought most audio equipment runs around 40V or so, a 50V capacitor may be on the borderline, but only half of the voltage should be across the bridge diodes...

**budm** · 10-30-2015, 09:59 AM

Re: What is this that has blown?

It looks like just a small power amp using TDA IC and just plain linear power supply.

**stj** · 10-30-2015, 09:59 AM

Re: What is this that has blown?

borderline my ass, your suppressing spikes - that's why the original smoked.

**mikay786** · 10-30-2015, 10:01 AM

Re: What is this that has blown?

Originally posted by budm

'so just measure the voltage of the wire that connects to the speaker?, If so can I just measure it on the board connector pin out for speaker?' Yes.
Can we see the pictures of the whole unit and the boards?

heres the full section

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**budm** · 10-30-2015, 10:04 AM

Re: What is this that has blown?

They are snubber caps (4) connected in parallel with each diode of the bridge rectifier.

**stj** · 10-30-2015, 10:07 AM

Re: What is this that has blown?

the caps are probably seeing about 35v
not including spikes.

What is this that has blown?

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