Mackie 1202

[gbono]

I have a Mackie 1202 that will only power up momentarily and+22 and CLP LEDs light up and then go off. Anyone have a schematic for the older microseries 1202? Does Mackie support discontinued documentation? THX

[soundguruman]

LOUD Technologies Inc. - Contact

You can beg them for schematics and parts, but it's been poor most of the time.
I have been very disappointed that the older products have very little or no support.
I have seen otherwise perfectly good mixers thrown away, for lack of parts.
And the customers have suffered a great deal, financially and otherwise.

[gbono]

07K[1].pdf

Loud was pretty fast getting this to me - though I had to send a legal disclaimer.

[Enzo]

Look at your power supplies first.

[gbono]

Tested the voltage regulators on the daughter board and the mc7915CT (neg Voltage Reg) is only putting out -9V. Either the regulator is bad or something is loading down the -15V rail. Hope it's the 7915 because I don't want to pull the mother board.

[Enzo]

Is there a resistor in series with the 7915 input? If so, measuer voltage drop to determine the current flowing through the regulator.

ANother test: is that regulator a lot hotter than the other one? If so, then we may be dragged down. If it is about the same, then the regulator itself is probably at fault.

Me, I'd slap in a new regulator at this point, as faster than those other things. And if it doesn't need it, at least the new one hasn;t been stressing.

[gbono]

I can see why these small mixers get the air lock when broken. Of course the -15 voltage regulator is okay. Must be one of the many 9 pin SIP op amps - but wihich one? It looks like U1 and U2 are the first opamps off the -15V supply - what's the best way to hunt down the offending load on the -15V rail?

[soundguruman]

I can see why these small mixers get the air lock when broken. Of course the -15 voltage regulator is okay. Must be one of the many 9 pin SIP op amps - but wihich one? It looks like U1 and U2 are the first opamps off the -15V supply - what's the best way to hunt down the offending load on the -15V rail?

Leave it on for a while and see which op amp(S) are getting hot.
Replace the hot ones. A shorted op amp gets very hot, don't burn your fingie!
Also you can disconnect boards if possible, and see which board loads the power supply too much.
Also if you have a scope, check the output pin of the amp stage, it will have DC on it when the amp is bad, a lot of times.

OR take it to the air lock and space it.
OR take it out to 1000 feet and sink it.
OR it makes a great door stop.

I have a pretty nice Mackie mixer here, and there is no power transformer for it. And so, it's a paperweight. Lack of parts and support, again.

[gbono]

yup U4/5 on the main outputs are getting warm - love that IR thermometer. Where do you get NJM4560S - Loud?

[soundguruman]

yup U4/5 on the main outputs are getting warm - love that IR thermometer. Where do you get NJM4560S - Loud?

4560 is same as 4558
do you like the fingimometer? ouch ouwie.

[Jazz P Bass]

Actually, the 4560 has wider bandwidth & a higher slew rate than the 4558.
The drive capability is also higher.
They are not to be compared as apples to apples.
http://www.pikpower.com/new%20site/n...ae/ae04053.pdf
http://synthdiy.com/files/2006/NJM4558_ae04052.pdf

[soundguruman]

Actually, the 4560 has wider bandwidth & a higher slew rate than the 4558.
The drive capability is also higher.
They are not to be compared as apples to apples.
http://www.pikpower.com/new%20site/n...ae/ae04053.pdf
http://synthdiy.com/files/2006/NJM4558_ae04052.pdf

You can install a 4558 or TLO 72 any time where a 4560 is used.
Oh yea, I forgot, your mixer will no longer pass 15 megahertz, my bad.

[gbono]

Mmmm I'm more conerned about the 9 pin vs 8 pin compatability - V(-) is pin 4 on the 8 pin version and pin 5 on what's in this circuit. I think I might have found some uc4570HA at MCM that might work.

[Jazz P Bass]

Mmmm I'm more conerned about the 9 pin vs 8 pin compatability - V(-) is pin 4 on the 8 pin version and pin 5 on what's in this circuit. I think I might have found some uc4570HA at MCM that might work.

Wow, I never saw a 9 pin SIP opamp.
These are not popular anymore.
At any rate, pin 1 & pin 9 are both V+.
So I would imagine if push came to shove, you could 'start' at pin 2, continuing through pin 9.
That would be the same as a 'standard' SIP.

[soundguruman]

Mmmm I'm more conerned about the 9 pin vs 8 pin compatability - V(-) is pin 4 on the 8 pin version and pin 5 on what's in this circuit. I think I might have found some uc4570HA at MCM that might work.

Oh Cry-Key.