Hey everyone!
I need help debugging a N61 Power Supply, maybe somebody can help me out...
In my last thread I asked about modding a Chinese PSU for use with Gefell Mics and what do you know, I found a N61V for cheap that looked pretty good, but of course not all that glitters is gold. Well.
First I removed the amplifier board, which was pretty easy and straightforward. So far so good, but then the problems started.
Although it looked like new, I was getting a weird 80V DC polarization Voltage and around 17 V?? for the tube heater. So I changed all Caps since I figured it's either going to be the old caps or the old tube that failed (which I dont know how to test anyway).
So, I changed the caps and evoila, I now have 124V polarization Voltage on pin 3 - nice!
However, I am still getting 16.8V for the Tube Heater?? I am thinking that it must have something to do with the Transformer (Choke) not pulling the Voltage down but how can I have ANY voltage at Pin 4 if the Transformer is not letting voltage pass through it?? Conversely, if it's passing voltage, how is it possible that it's the same voltage before and after the transformer??
Last question/Option - I have a very simple DMM, could this be some kind of measurement error on my part...?
I am thankful for any tips - The schematic I am using is attached,
David
I need help debugging a N61 Power Supply, maybe somebody can help me out...
In my last thread I asked about modding a Chinese PSU for use with Gefell Mics and what do you know, I found a N61V for cheap that looked pretty good, but of course not all that glitters is gold. Well.
First I removed the amplifier board, which was pretty easy and straightforward. So far so good, but then the problems started.
Although it looked like new, I was getting a weird 80V DC polarization Voltage and around 17 V?? for the tube heater. So I changed all Caps since I figured it's either going to be the old caps or the old tube that failed (which I dont know how to test anyway).
So, I changed the caps and evoila, I now have 124V polarization Voltage on pin 3 - nice!
However, I am still getting 16.8V for the Tube Heater?? I am thinking that it must have something to do with the Transformer (Choke) not pulling the Voltage down but how can I have ANY voltage at Pin 4 if the Transformer is not letting voltage pass through it?? Conversely, if it's passing voltage, how is it possible that it's the same voltage before and after the transformer??
Last question/Option - I have a very simple DMM, could this be some kind of measurement error on my part...?
I am thankful for any tips - The schematic I am using is attached,
David