REQ: Mackie 1202 Original Schematics Please?

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Hi, does anyone have a scanned in original pdf of the Mackie 1202 mixer?

Kind regards, Simon.

 

[cyrano]

Thought I had one, but the pdf is damaged. I'll see if there's a chance of repairing it...

 

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Thought I had one, but the pdf is damaged. I'll see if there's a chance of repairing it...

Ah! cheers, yes that would be fantastic, thank you if you cant repair, please send anyway and i can have a go at the repair too

 

[living sounds]

There you go.

 

[cyrano]

Thanks. Mine was rotten to the core, as are several others in the Mackie folder.

 

[ruffrecords]

What is the part number of the LED VU meter chip they use? I cannot read it on the schematic.

Cheers

Ian

 

[fznuk]

thank you so much for the pdf! cant see the power supply on it though which is what i needed? I think one of the regulators has gone bad?

 

[living sounds]

I do think it's a really simple, standard supply, utilizing the common L7815, L7915 regulators. Most likely culprits are the capacitors. Try replacing the smaller ones (22uf I think) first. Use normal (not low-ESR) ones.

 

[rogs]

What is the part number of the LED VU meter chip they use? I cannot read it on the schematic.

Cheers

Ian

Looks like the Sanyo LB1482M... The only data sheet I've seen is in Chinese (at least I think it's Chinese?) .
Pin references correspond to the Mackie schematic
https://www.datasheet-pdf.com/PDF/LB1482M-Datasheet-SanyoSemiconductor-526829

 

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I do think it's a really simple, standard supply, utilizing the common L7815, L7915 regulators. Most likely culprits are the capacitors. Try replacing the smaller ones (22uf I think) first. Use normal (not low-ESR) ones.

Im getting over -16V out the 7915 reg - you are correct in the cap values 22uf wit two larger 2200uf caps too. i will swap them out as yes, sometimes hard to tell if they are failed unless tested as they dont always leak or bulge cheers

 

[soundwave]

Here two original PDF of Mackie MS1202 mixer service manual and schematics.
Cheers HERB

 

[robovox]

The 7815/7915 regulators are strapped with resistor dividers to raise voltage output to +/- 16V. How high does the -16V rail measure?

Those 22uF caps on the regulator outputs (C37/C38) should be at least 25V, not the 16V shown in the schematic.

In what way is the mixer operating improperly?

 

[Brian Roth]

After glancing at the schemo, I see another "gotcha"....phantom resistors are only 0.25 Watt. Normally not an issue until a shorted mic cable is used. The power dissipation of the associated resistor(s) is over 0.33 Watts.

It's not just Mackie. I've seen it in many mixers/consoles....including Big Names. Not an issue, you say? Maybe not. But, I've seen more than a few "browned" resistors, especially in equipment that's been in service for awhile. For instance, in a studio, a dodgy cable can be left plugged in and sitting on the floor for weeks.

Bri

 

[signup]

The 7815/7915 regulators are strapped with resistor dividers to raise voltage output to +/- 16V. How high does the -16V rail measure?

Those 22uF caps on the regulator outputs (C37/C38) should be at least 25V, not the 16V shown in the schematic.

In what way is the mixer operating improperly?

ah! that explains -16V so thats all ok!


High DB noise on the main outs without anything plugged in, so im guessing caps?

Cheers, Si.

 

[signup]

After glancing at the schemo, I see another "gotcha"....phantom resistors are only 0.25 Watt. Normally not an issue until a shorted mic cable is used. The power dissipation of the associated resistor(s) is over 0.33 Watts.

It's not just Mackie. I've seen it in many mixers/consoles....including Big Names. Not an issue, you say? Maybe not. But, I've seen more than a few "browned" resistors, especially in equipment that's been in service for awhile. For instance, in a studio, a dodgy cable can be left plugged in and sitting on the floor for weeks.

Bri

good to know! thank you And I know the owner of the mixer uses phantom power too so i will have a look

 

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Here two original PDF of Mackie MS1202 mixer service manual and schematics.
Cheers HERB

Thank you

I do think it's a really simple, standard supply, utilizing the common L7815, L7915 regulators. Most likely culprits are the capacitors. Try replacing the smaller ones (22uf I think) first. Use normal (not low-ESR) ones.

thank you

 

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There you go.

thank you