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Hello Forum . I have a Mackie 808S that belongs to a venue I play at . It developed an issue where the sound would get real low then real loud . The LED peak meter for the left channel (Ch1) Has no output (no Lights) when this happens . I set it up with two speakers on the main channel and it seems to break up immeddiatly . If I change the config to main / monitor and only use the monitor output it seems ok . So For now Ill assume the issue is with channel 1
I Am not great with this stuff , better with tube amps so I decided to get the schematic and do a simple power supply test . With the amp on and two speakers connected the dc rail voltage are as follows 100+ =92.4 , -100 = -92.3 +90 =82.8 , -90 = -83 +45=41.2 -45 = -41
The test point on the bottom of the board are 15+ and -15 and there is a +5 supply .. the 15 read exactly 15.1 and the 5 volt is at 4.91
The first question is do I have a power supply issue or are these values in range .
Second question how do I test to see where the break or problem might be . Im good with a scope and I have a signal generator . Any help would be appreciated
One more thing it seems that when it warms up the problem goes away , but I have not completely proved this yet .
Scott.
I Am not great with this stuff , better with tube amps so I decided to get the schematic and do a simple power supply test . With the amp on and two speakers connected the dc rail voltage are as follows 100+ =92.4 , -100 = -92.3 +90 =82.8 , -90 = -83 +45=41.2 -45 = -41
The test point on the bottom of the board are 15+ and -15 and there is a +5 supply .. the 15 read exactly 15.1 and the 5 volt is at 4.91
The first question is do I have a power supply issue or are these values in range .
Second question how do I test to see where the break or problem might be . Im good with a scope and I have a signal generator . Any help would be appreciated
One more thing it seems that when it warms up the problem goes away , but I have not completely proved this yet .
Scott.
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