JRS04 Adjustment Procedure

[goldkenn]

Due to the article of JRS04 not fully finish, and don't know why I can't open the link to the article of JSR01, please kindly advise how to set and tune the two trimmer?

[peranders]

The output voltage is set by two things, the voltage reference (LM329, LM431 etc) and the gain in the circuit. Let me come back is a few hours with more details.

[peranders]

If you use LM431 you have R43 and R45 and possibly also R41 and P3. The voltage reference is adjustable.

The feedback (gain) is formed by R33 and R37//R39. The gain = R33/(R37//R39) + 1

[goldkenn]

I use LM431 (actually TL431 since no LM here in
Hong Kong, but they suppose to be exactly same) and have already soldered all parts refer to the excel list, as you know I use it for QSXM2, the transformer is 2 x 24VAC.

In this case, except I know the output should be at 18VDC, but where is the test point of P1/P2/P3/P4 and what read out should I get?

[peranders]

If you use the TL431 you should tune it up to 9 V and let the gain stay at 2.

R33 1k
R39 1k

R43 8k2
R45 3k3

=> 17.4 V

Not mounted
P3
R41
R37
R35
P1

This is valid for the positive half.

[goldkenn]

So as I have soldered all parts refer to the file "jsr04r0_componentlist", right now what I need is only change R43 from 6.8K to 8.2K, and unmount the P3/R41/R37/R35/P1?

For the negative half, I should change R44 from  6.8K to 8.2K, unmount P4/R42/R38/R36/P2?

So as long as I use a 24VAC transformer and supply for QSXM2 only, there will be no tuning needed refer to your insturction, am I understand everything right?

[peranders]

Correct.