R2001C RF output has a DC voltage?
Posted: Sun Jun 26, 2022 2:03 am
I have been working on an R2001C with minor problems, and I have noticed that the output RF rides on a positive DC voltage of about 3 volts, and I suspect it is NOT normal, IF, I read the schematic right.
On the A5A2 card, there is a circuit that has a bias network tied to the +5 volt bus. Sheet 3 of 3, there is a relay, K201-228-4-1a that connects the output to the inductor, L247, that is connected to the +5 volt bus. However, I do not know what the reason for that connection would be.
I have had a few failures where the unit goes into a reset mode and the screen has a warning of the failure of the non volatile ram and needing to be reset.
It has worked well after, except for the DC on the output. Do I need to see if the relay is stuck closed?
On the A5A2 card, there is a circuit that has a bias network tied to the +5 volt bus. Sheet 3 of 3, there is a relay, K201-228-4-1a that connects the output to the inductor, L247, that is connected to the +5 volt bus. However, I do not know what the reason for that connection would be.
I have had a few failures where the unit goes into a reset mode and the screen has a warning of the failure of the non volatile ram and needing to be reset.
It has worked well after, except for the DC on the output. Do I need to see if the relay is stuck closed?