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Does anyone have a troubleshooting guide for the Mackie SRS1500? I am experiencing issues....currently see a -64 Vdc on the speaker output. Any ideas on how to troubleshoot this issue? Thanks in advance!
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Guide? Pardon me while I chuckle. No, they issue schematics, that is about it. Mackie will send it to you if you ask nice. They will likely ask you to agree not to post it on the internet.
DC on the output? Same as any amp, start looking for shorted output transistors, their drivers, and so on. Also check for any open resistors associated with any bad transistor.Education is what you're left with after you have forgotten what you have learned. -
It is a 5mb RAR type file that has all the schematics compacted together, download winRAR if you need a good program to open the file.
Diagramas Mackie SRS1500 Service Manual rar Mackie SRS1500 Service Manual rar - AUDIO, mackie
Note: Just scroll down to the bottom of this page and click the blue hyper-link.When the going gets weird... The weird turn pro!Comment
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Cool find.
Thanks.Comment
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Thank you all for your input. I will start testing all transistors. For now, the board does not appear to have any burned components.Comment
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SRS1501 if that is similarComment
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Dusting off this thread, because.....well, you know. "Service manuals" without so much as a voltage chart, oh well.
Presumably, this beast is a Class G amplifier. The optocouplers are driven linearly but they have Schmitt-trigger circuitry, hence "G" and not "H".
Trouble is, the optocouplers are never turning on, therefore no MOSFET gate drive, and consequently the collectors of the output transistors remains steadfastly +/- 13.8 volts, measured with input signal (to the board, at J4) ranging from 0 to approximately 250 mV RMS. Looks to me like Q11 and Q12 are always conducting.....and I can't see a situation whereby these WON'T be conducting. Thus, no voltage drop across the optos' LEDs, and thus no opto output.Comment
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