Hi I have a problem with an old Mackie 1202, that I have for over 20 years, I love this piece of equipement, easy to use and sound pretty decent, recently I notice that I have a hum, a noise through the master output and the headphone output that goes away after the mixier gets warm, take about 5 minutes and it does not come back, let it cool and here it is again, so I though that perhaps it was the two caps 2200uf of the power supply that was the cause, I changed those but still the same problem, perhaps it the two voltage regulator(transistor) of the power supply 7815A and 7915A but I'm not certain, I may try that anyway and see, caps were only $9 for 3, 7815A and 7915A are $2 each on ebay.
Anyone with a similar problem!
thanks!
Anyone with a similar problem!
thanks!
Don't throw parts at it, get out a scope and watch the power supplies. Are they up and stable or are they changing with the symptom? Is there excess ripple in them?
And it may not be a part at all. Over the years Mackie has had a problem with ribbon cables. I don't recall the insides of this unit, but the ribbon header female connectors get oxidized. Usually pulling them half way off and pushing them back down refreshes the contact surfaces.
And it may not be a part at all. Over the years Mackie has had a problem with ribbon cables. I don't recall the insides of this unit, but the ribbon header female connectors get oxidized. Usually pulling them half way off and pushing them back down refreshes the contact surfaces.
I agree with Enzo. Check connections. Rule of thumb is that about 80 per cent of problems with electronic circuits are connection related. Check and clean (if needed ) all connector points. Corrosion is electricity’s enemy. If you use isopropynol as a cleaning agent, make sure you rub surfaces well after application. Alcohol tends to spread the grease/dirt/bad corrosive stuff around on the surface so you have to remove it totally.
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