Hi All sorry for basic questions but I really need some help.
I bought a secondhand ALWSR several years ago. I had too many projects on so it went in the spares box. I have now finally got it out and am trying to set it up for +5V.
So the changes I made were:
Change ZD1 to a TL431.
R8 and R9 were changed to 1K each.
R5 and R7 were strange values so I changed them to 249R and 499R.
When I tested the board the output is 7.8V not 5V!
I checked the voltage across ZD1 and it 2.49V which sounds right.
Voltage across R8 is 4.37V
Voltage across R9 3.51V
Can anybody advice me on what to try changing next or is the board previously damaged?
Cheers
Ian
I bought a secondhand ALWSR several years ago. I had too many projects on so it went in the spares box. I have now finally got it out and am trying to set it up for +5V.
So the changes I made were:
Change ZD1 to a TL431.
R8 and R9 were changed to 1K each.
R5 and R7 were strange values so I changed them to 249R and 499R.
When I tested the board the output is 7.8V not 5V!
I checked the voltage across ZD1 and it 2.49V which sounds right.
Voltage across R8 is 4.37V
Voltage across R9 3.51V
Can anybody advice me on what to try changing next or is the board previously damaged?
Cheers
Ian