toa 900 series 2 help

[sdnnet3]

i'm trying to figure out what's up with my amp system... i'm so so with electronics...

it's distorting/clipping the sound somehow. i'm trying to figure out where it could be doing that. the audio is still there, but it's got a cracking static sound... kind of like the speakers are blown, only they aren't.

any ideas where this could be happening in it... pre amp, power amp... the signal coming in is clean, but the amp is distorting it somewhere.

any help would be greatly, greatly, appriciated.

peace,
clayton

[gni]

Check those electrolytic caps. . .especially in the power supply.

They do tend to go dry. . . .If the amp is more that 6 years old. . .
and it has been used or on much of that time. . . .just flat out
replace them. . .

Let us know how this works.

Chris Browne

[sdnnet3]

ok... i'll give it a shot. can't remember off the top of my head what they were, but whatever they were, they are very large (to me).
i know the diodes are out... looks like somewhere in the preamp stage.
replaced the diodes, and it was better for about 2 or 3 weeks, and then they went out again, so i'll give the cells a shot.
let ya know how it turns out for sure.

[Original Burnedfingers]

Toa 900 Series II what?

Straight 900 is a unpowered mixer.

903 is a 30 watt mixer amp. 906 is a 60 watt mixer amp. 912 is a 120 watt mixer amp.

I doubt if its the power supply caps. I have never had to replace any caps in the power supply yet and the stuff I fix runs 24/7.

[gni]

I think I use the 'replace caps' as often as computer tech support
uses 'reload the software.' I don't like to use it but on many systems
that are built to 'just work', those caps take it by being run a near
voltage. Some caps are better than others, some batches of caps
are total junk. But the old electrolytics do dry out with near voltage
and high heat conditions. In the end, I have not seen the piece of
equipment; but heat kills electronics.. . .wouldn't it be nice to drop
all your electronics into liquid nitrogen. . .run at perfect light speed!

Equipment that is run 24/7 tends to last longer than equipment
that is shut off and on. . .the duty cycle of on/off really can take
a toll on caps and other sensitive electronic due to high currents
and spikes.

It is strange that the diodes are crapping out. . . transformer coils
beginning to send too high of voltage? Caps burned out. . .so
basically a short, thus too much current. . .then dead diodes. . .bad
electricity at the AC mains?

Just more food for thought!

Chris

[Original Burnedfingers]

Good points

[Original Burnedfingers]

i'm trying to figure out what's up with my amp system... i'm so so with electronics...

So what do you have for a system anyway?