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 Post subject: need some technical help with m100.
PostPosted: Tue May 21, 2019 10:25 am 

Joined: Sat May 11, 2019 10:53 am
Posts: 2
i'm doing some servicework on an m100 , but i'm not sure if i'm correct or not. the emitterresistors measure zero mV , shouldn't there be a few mV for bias ? and the outputs measure 88mV and 180mV to earth/ground , isn't this to much ? any suggestions about whats eventually wrong


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 Post subject: Re: need some technical help with m100.
PostPosted: Wed May 22, 2019 2:13 am 
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Joined: Mon Mar 21, 2011 4:47 am
Posts: 255
Location: Finland
You're right, the bias current should show up as some mV across the resistors. Maybe 5mV, I can't recall exactly. The pots on the PCB are for adjusting bias.

DC offset at speaker connectors should be 30mV or less. Large values indicate the amp has had a hard life and the output transistors are "leaking current".



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