Highly doubt you’ll see anything obvious but you never know.

I feel for ya…You think of all the hours that gets put on hardware in a commercial studio, and then how few hours we home users put on stuff. 4 years and how many true “home” hours? Not saying much for their component quality.

Well what ever you decide to do dont throw it away. You can always gut the “tronics” drop in a crossover and run an external power amp.




Duff, the problem is, when I hear words like "drop in a crossover," I realize that I have spent my time learning a lot of things, but that's not one of them. I know what one is, and what it does, but I don't know enough to know how to drop one it. Sad, but true.
:laugh: He looks so pissed too

aaahhh I remember my first crossover…it was an Ashley worked real well but alas it was not stereo.
I eventually graduated to the Rane gear and it has been smooth sailing ever since.

I’m not sure about the drop in, mine are in racks, but I’m assuming you can get small ones to insert into the circuitry of a speaker/tweeter situation.
But if “drop in” is lingo in for putting one in the signal chain that I could rap my brain around. :agree:


TomS googles crossover plugins

One other thing to consider with this failure is a fault in the overload protection circuit itself. I once had an amp that went into protection mode due to a fault in the protection circuit and not the amp.

I’ve not looked at the schematic for this amp yet. Will check it out shortly but I need my first cup of tea of the day before : -)

That’s interesting Mark

Quote: (Levi @ Jun. 06 2011, 11:15 AM)

That's interesting Mark

Yes, I need tea before reading a schematic :)

Anyway, Tom, I've had a bit of a look, and here's what I would do if I were you,

1. Pull the thing apart. Carefully! (power disconnected of course).

2. Make a note of any connectors that you undo. Mark with tape if necessary to show what goes where.

3. Do a good visual check of the components. Look for any signs of damage, burning, leaking, warping of a component's housing. I know that's possibly a bit tricky if you don't know what things should look like. (I'll post a few pics below).

4. Look for mechanical problems. The majority of electrical problems are actually rooted in mechanical problems - dodgy connections, things touching that shouldn't be. Remember that a speaker vibrates so over time things can move.

5. Check all the solder joints. Make sure they are all good.

6. Try the speaker check I suggested earlier. You will need to disconnect the speaker from the circuit board (one wire will do). I can't see how easy that will be from the schematic. May just be a connector or you may need a soldering iron.

7. Use your multimeter to check the DC power rails. Looks like it should have +38v and -38v going into the regulator and +15v and -15v coming out. Obviously you will have to power the thing up to do these checks. Be careful, but no need to be scared of it. Just be sensible.

A note on the voltages. The psu has + and - rails. That's (eg) 38v "above" ground and 38v "below" ground. Pin 3 on connector J1 is ground. If it's a digital multimeter then the meter should show plus/minus accordingly. If it's an analogue meter then the pointer will deflect the wrong way if you have the probes round the wrong way.

Ok, that'll do for now.

It’s a digital meter. Why does “crossover” make me think of this bar that was next door to one we used to play?

oh… pics.

Blown capacitors.
Sometimes they just have a bulging top without the leakage:

There are different types of caps.
They are measured in Farads (well usually micro farads and pico farads) so will usually have the cans marked with uF or pF.
Oh and they have two legs.

Again different types but have two legs and have coloured stripes (that denote the value and tolerance).

The opamps and chips are the black flat things with lots of legs.

This is pic of the power amp (LM3886) module.
Yours will most likely be bolted to a heatsink (chunk of metal)…

And here’s the op amp for the preamps…

Quote: (TomS @ Jun. 06 2011, 11:57 AM)

Why does "crossover" make me think of this bar that was next door to one we used to play?

I thought it was something to do with angry cricket bowling.... but my US friends may not get that one.. :D

There ya go Thomas another task as if the wifEpoo sent it her self. She must have known you where plAnning some musical ruckus
Great nTrack notes MarkA

Levi, you already know that my wife fully supports my hobby! :) Mark, those are not at all unobvious, are they?

BTW, the bar next door was called Rods.

Remember … electrolytic caps are polarized. If one is blown and needs replaced, make sure you drop the replacement in with correct polarity.


PS The cans with the cracked tops in Mark’s pic are eletrolytics…