SSR03 5V problem

[Andreas Sellenthin]

finished 2 pieces 15V boards with no problems but my first 5V board doesn't work.
ALL LED's don't shine. Double checked, see no mounting error.

LM317/337 input 13,4V, out 11,7V, Adjust 11,2V

On Opamp:

PIN2 4,15V
PIN 3  3,5V
PIN6  1,02V

Any idea?

Best regards.
Andreas

[peranders]

J1-J4, tin blob?

Voltage across anode and cathode VR1? Should be 2.50 V.

[Andreas Sellenthin]

yes.

Both opamps AD825 have 11,7V supply voltage

[peranders]

Are the LED's mounted right? You can diode measure to check this if it's hard to see the polarity mark.

Do you have the same problem with the negative half?

[Andreas Sellenthin]

H1/H2 mounted right, both in same direction,see picture
DZ1/2 also (opposite direction as H1/2)

same problem on negative half

[peranders]

Q7, voltage on emitter-collector (ground)?

Q1, collector - ground voltage?

The LED's looks suspicious?

Flat side on H1 should be visible in the photo.

[peranders]

Good, H1 is OK.

LM431? Voltage?

R25 voltage to ground?

I deleted your poll. This was a mistake from your side?

[Andreas Sellenthin]

Q7, voltage on emitter-collector =0,009V

Q1, collector - ground voltage= 11,1V

[peranders]

Q7 seems broken. Can you do diode measurement. Check also soldering so you don't have any connection to ground on the emitter. Double check the orientation of the LED in the DZ1 position. The flat side should point at the opamp.

[Andreas Sellenthin]

LM431 2,51V
R25 to gnd 10,4V

[peranders]

2.51 V good.

R29 voltage, on both sides measured to ground? 10.4/2 should be 5.2V

Check that the LED's are OK. Should emit weak light with an universal instrument. LED's are not too hard to break with heat.

Do you have 11 V across the LED at DZ1? If so, it is mounted in the wrong position.

[Andreas Sellenthin]

LED's are ok (1,8/3&they emit light :lol:), soldered out&in, direction is ok.

DZ1 9,5V accross the LED

R29 4,2V / 4,11V

Q7 is ok, no emitter connection to ground

[Andreas Sellenthin]

Now it is working :lol:

MY stupid mistake:
After hours of searching i looked closer to the schematic and realized that the LED in the DZ1/DZ2 Position have to be in the opposite direction as the zener Diode! :-D

All the time i checked cathode & anode of the LED but in the wrong way, grrrr :evil:.
Seems i need new glasses....

Thank you for the support.

[peranders]

Good! The weekend is saved.

[Andreas Sellenthin]

Hi,

just measured, perfect symmetry with 330mA output (5,04V both sides) :-D

I use a AC 9V transformer from RS and no resistors for wire bridge/smoothing section. 7,58V Output at LM317.

@peranders: Do you think there is any room for resistors in wire bridge or smoothing section?