Hi all!

I am trying to repair a Vibe 1200D amplifier. It just blows the fuse
when turned on, even with no load.
Any ideas where I should search the fault? The FETs look OK.

BR, Tuffe

"Tuffe" wrote in message
...
Hi all!

I am trying to repair a Vibe 1200D amplifier. It just blows the fuse when
turned on, even with no load.
Any ideas where I should search the fault? The FETs look OK.

BR, Tuffe


If power supply FET's are OK then look at the rectifier, if it's shorted it
will blow fuses, but also known to blow supply FET's. Also look into the
driver circuitry for the PS FET's are they colliding electrically?

Checked the Finals? Usually the protect circuitry will keep the fuses from
blowing but....

Is there a big diode strapped across the power input? Check it, back EM
Pulses from AC comps, starters and big relays can get these, it's rare but
it happens.

When you say turned on what do you mean? Power applied and all is good, hit
the remote and bang? Or as soon as you apply B+/Gnd.

Chad

Thanks for the tips Chad!

Yes, when power power and ground is applied nothing happens, but when
remote gets 12V the supply current is way beyond what it should be and
blows a 30A fuse.
With a 5V voltage the current stays around 0.5A, but when raised to
about 5.8V the current keeps rising (I get 2A from the lab power
supply).
I will go through your tips and be back with my findings.

Tuffe

Chad Wahls wrote:
"Tuffe" wrote in message
...

Hi all!

I am trying to repair a Vibe 1200D amplifier. It just blows the fuse when
turned on, even with no load.
Any ideas where I should search the fault? The FETs look OK.

BR, Tuffe



If power supply FET's are OK then look at the rectifier, if it's shorted it
will blow fuses, but also known to blow supply FET's. Also look into the
driver circuitry for the PS FET's are they colliding electrically?

Checked the Finals? Usually the protect circuitry will keep the fuses from
blowing but....

Is there a big diode strapped across the power input? Check it, back EM
Pulses from AC comps, starters and big relays can get these, it's rare but
it happens.

When you say turned on what do you mean? Power applied and all is good, hit
the remote and bang? Or as soon as you apply B+/Gnd.

Chad