24V supply voltage not working: IC31 resistors
Several resistors have been changed. It should be changed in the schematics the following ones:
- R229 and R230: they should have a value of 1K5. They have been
changed to 510R and 1K, respectivelly.
- R259: changed to 1K instead 100R.
Then, to improve the stability of the feedback the following improvents have been carried out:
- Parallel capacitance of C190, C191: use only one capacitor of 68pF.
- R234 changed to 10K. In this case a good serial resistance of
R231-R235 is around 75K.
By changing these values, better phase and gain margins are achieved.