Swr combo blowing fuses

[jezzaboy]

I`ve got a SWR Workingmans 15 combo. I, foolishy, gave someone a loan of it and from what I can gather he heard some buzzing through the combo and decided to disconnect the internal speaker and run an extension speaker into it to see if it was a problem with the sinternal speaker. Result, the same buzz.

Then, you`ll like this, he pluged another amp head into the swr ext speaker socket and turned em both on. The SWR made a phww noise and chucked it. Having had a look at it, the fuse has blown (the one on the back of the amp head), so, I changed the fuse making sure that it is the same kind as in the manual but it keeps blowing.

Any ideas? Is it goosed? Has it mabye blown something inside?

Next question. Anyone know of any amp repairers in Glasgow area?

Any help would be appreciated.

Jez

[icastle]

[quote name='jezzaboy' post='1125334' date='Feb 12 2011, 07:35 PM']I`ve got a SWR Workingmans 15 combo. I, foolishy, gave someone a loan of it and from what I can gather he heard some buzzing through the combo and decided to disconnect the internal speaker and run an extension speaker into it to see if it was a problem with the sinternal speaker. Result, the same buzz.

Then, you`ll like this, he pluged another amp head into the swr ext speaker socket and turned em both on. The SWR made a phww noise and chucked it. Having had a look at it, the fuse has blown (the one on the back of the amp head), so, I changed the fuse making sure that it is the same kind as in the manual but it keeps blowing.

Any ideas? Is it goosed? Has it mabye blown something inside?

Next question. Anyone know of any amp repairers in Glasgow area?

Any help would be appreciated.

Jez[/quote]

Oh lordy.
The output stage will have been fried - so any semiconductors in the path of the signal from the speaker socket will have blown for certain, passive components might have survived, but no cast iron guarantee of that.

Without seeing a circuit diagram it's hard to know just how many components would be in that path and at what point blown components would have prevented the signal from progressing further.

This could potentially be a large repair bill.

[JTUK]

What on earth did he think he was doing..??

Jeez...some people..and you happen to have been unlucky enough to lend this guy the amp.

I doubt he will want to cough up for the bill...but I agree with the above, best of luck finding someone.
Anyone decent will be able to sort this out but what damage and how much it'll cost, I have no idea

[jezzaboy]

Thanks for the replies guys. I still haven`t got a sensible answer from him as to why he plugged in the other amp head. I have loaned him gear before and he always looks after it. Needless to say, I won`t be doing that again....

If it`s potentialy an expensive one, ah well, I always needed a better 15" bass cab.

Jez

[JTUK]

Reading that reply, I am now confused.

I thought he plugged an amp into the SWR extn socket output on the amp ?? which would mash the internals of that amps output stage, IMO...
or he plugged both amp outputs into the speaker cab..which I would have thought would be a closed connection to eliminate this type of dumb thing.
If the latter...you ( he ) would have probably blown that speaker.

The best thing he could have done..is do the gig carefully with the existing SWR combo and report the fault to you...adding he would help out with a payment as it may have happened on his watch.

Interested in hearing what an amp tech makes of all this... I think if the first instance is on the right lines, you'll need the output stage of the amp repaired..and it may be as little as a blown output capacitor or..???

No expert here, and just guessing from past expereince of blown output stages. Not from a dumb thing like this guy did though..hasten to add
That was the beauty of being brought up on flakey valve amps and wimpy speakers..you had a few failures and you learned quick.
Transistor amps are so more resilant to abuse..but there is a limit.

hope you find decent guy...if it is just a few odds and sods if you are lucky..I would expect an independant..ie, not a shop with overheads and mark-up for subbing this out, to be from £35 or so for a few hrs work. Guesstimate ..

[Roland Rock]

[quote name='JTUK' date='Feb 13 2011, 09:15 AM' post='1125682'

I thought he plugged an amp into the SWR extn socket output on the amp ?? which would mash the internals of that amps output stage, IMO...

[/quote]


That's the way it reads to me, too. If you're confident/knowledgeable enough to start disconnecting speakers etc. to do 'controlled experiments', then how could you do such a stupid thing?
Anyway, hindsight etc.

Hope it's cheap and painless

[jezzaboy]

Sorry if I am confusing youz guys.

What he did was disconect the internal speaker from the back of the SWR and plugged in another amp head into the external speaker socket on the back of the SWR and turned on both amps. He says that he did this to by pass the SWR amp and see if the buzzing noise was coming from the SWR head.

I know, it`s bloomin crazy and I can`t really get my head round it but at least he was decent enough to put his hands up and admit what he had done. He could just have said it chucked it. I have had an e mail from him and he is willing to splash the cash for the repair/replacement.

Jez