No Power, please help

[Leemo]

Hi guys, I need some advice please.

I have two Ashdown ABM amps. I mistakenly connected the speaker output socket of one to the other. When I connected my guitar both amps died. The kettle leads are fine & the internal fuses look ok, I have counted seven, but there is no power to the amps.
Have I cooked something, or is there a quick fix?

Any guidance would be greatly appreciated.

Regards, Leemo[attachment=209210:Ashdown.jpg]

[mikeydee]

I take it that you mean that you connected the output of amp A in to output of Amp B, correct?

Bad luck, but I am surprised that a fuse hasn't blown - most likely on the power-amp board.

There are several fuses on the main amp board
also a mains fuse built into the mains input connector on the amp. There is a little drawer containing a fuse that you need to prise out with a screwdriver.
some transformers also have fuses built into them nowadays and these are not servicable.

Always check fuses [b]removed from the circuit board [/b]with a continuity meter. Inspection is not good enough and moreover measuring when fitted to fuse holder can give false success readings because of other parts that are in circuit like transformers and heater filaments ( valve amps only).

[b][color=#ff0000]Never open an amp while it is connected to the mains.[/color][/b]

Good luck with fix. . .

[Leemo]

Hi Mike, thanks for your response.

Yes I did connect speaker output from amp A to speaker output of amp B.

I will try & find the little draw you mentioned & put a meter across the fuses, ( I will have to get one first), as i have only inspected them visually.

Many thanks for your advice.

Regards, Matt

[Leemo]

BINGO,

Mike you are a genius !

I found the little draw you mentioned & low & behold the fuse has blown in each amp. i will get new ones tomorrow & replace them. Hopefully this will rectify the problem.

Thanks again, Matt

[mikeydee]

Good stuff.

They are 20mm fuses. Mailing sell them for about £2 for a pack of ten. Check the rating carefully and match the A or ma current ating and also the speed T=slow blow and F=fast blow.

[Leemo]

Bingo has turned to bugger,

Changed the fuses in the draws, powered it up, & they have blown again, and had smoke from the first circuit board.

Aaaaaaaaaaaahhhhhhhhhhhhhhhhh !!!

[mikeydee]

Ah Shame. Do you know which bit of the amp smoked?

Quite likely that the power transistors on the power amp are toast. If the board is damaged (charred) then reliable repair isn't achievable. If not then maybe. . . Ashdown do supply parts to techs but I am not sure if they do to general public you need to call them tho as their website is just t shirts and speakers.

I guess it is time to look up your local amp tech.

[Leemo]

I have been in touch with Ashdown, they say they could repair them, but I will have to get them to Chelmsford, 180 miles from me.

I have a local amp tech, so I will get them to him.

Many thanks, Mike, for you input.

[mikeydee]

Hope doesn't cost an arm and leg.