Isaac C.
Cat Hoarder
Hello everyone, I acquired a Lafayette LR-3500 back in February in working condition. Upon acquiring it, I performed some basic servicing. I created this thread in order to figure out how to adjust the bias and did so with success. This receiver does not have a dc offset adjustment but only potentiometers for bias. The problem is that when I initially measured the left channel at roughly 15mv and the right channel at 2mv. The problem is that upon checking it today, the left channel has drifted to roughly 23mv and the right to 6mv. I know most people would consider this to be acceptable. However, I have also have noticed the speaker protection relay has been taking longer to engage, usually between 4 and 5 seconds. I am not sure if this has anything to do with dc offset, but I am wondering if a component is going bad.
Any help or suggestions are appreciated. Please refer to my first post for more pictures and background. Pictures four and five are the power amp board. Thanks in advance!
Last note, unlike some receivers where idle current is measured through a removed fuse, I had to measure indirectly across the white resistors. These bias adjustments too have drifted.
https://audiokarma.org/forums/index.php?threads/help-wanted-biasing-a-lafayette-lr-3500.857508/
Any help or suggestions are appreciated. Please refer to my first post for more pictures and background. Pictures four and five are the power amp board. Thanks in advance!
Last note, unlike some receivers where idle current is measured through a removed fuse, I had to measure indirectly across the white resistors. These bias adjustments too have drifted.
https://audiokarma.org/forums/index.php?threads/help-wanted-biasing-a-lafayette-lr-3500.857508/