Jsr03 9v Problem

[Branko]

Hi,

i build a jsr03 9V as stated on BOM with two red LED. I double checked the parts. if I connect to power (without load) the two LED light up for about 2 secondes then stop light. the V in is about 18,5 V and the V out is 16,1 V (with tin bolbs on the sense pads) i use an lm317, ad825, bd 139 and tl431. R10 is jumper, r13 10K. what to check where to measure?

thx

Branko

[peranders]

R12 not mounted? Only R11?

Start to measure around the opamp, pin 2, 3 , 6 and 7

The values should be

Pin 3 Approx. 9.50 V
Pin 2 the same as pin 3 +- 2 mV
Pin 6 7-9 V
Pin 7 19 V

[peranders]

You have:
Vin 18,3 V (no load) IC3 (AD825) pin 2: 0; 3: 8,72V; 6: 14,98V; 6: 15,6 V

8.72 V is good
Pin 2, R8, R9 are both 1k? R10 jumper or resistor?

Have you connected the sense inputs? Put a tin blob on the J1 and J2 on the solderside.

[Branko]

Hi,

R10 jumper. Tin blobs are in place. R8/R9 1K.
Moved R11 (47R) to R12. R11 open

Branko

[peranders]

Can you measure across R8 and R9?

[Branko]

R9 0V; R8 0V

Branko

[peranders]

Check R8 and it's connection to the output. R3 is connected to R8 and the LM431 seems to be working.

[Branko]

Hi,

I will check after noon when I am back home. I use a TL431 not a LM431. Is that a problem?

thx

Branko

[peranders]

Should work and you have also nearly 8.5 volts which is correct for 19 V out. Check carefully that all parts are their right positions.

[Branko]

Hi,

double check sometimes is not enough :oops:! As I tried to move R11 to R12 I moved R8 to R11.

After correcting these things here are the Values:
Vin 18,5V (LEDs shows light for a moment, then goes dark) Vout 16,5 V

IC4: Pin 2 -- 8,06 V Pin 3 -- 8,52 V Pin 6 -- 15,6V  Pin 7 -- 16,53V

R3 -- 7,33 V  R7 -- 0,0 V  R8 -- 8,05 V R9 -- 8,05 V R10 -- Jumper(would 470R be better option?); R11 47R in Place; R12 open.
IC2 TL431 not LM431

Branko

[peranders]

9 volts out, you should have 4.5 volts and the reference. Could you repeat the resistor values around the TL431?

I was into 19 volts out which somebody wanted.

[Branko]

Hi,

the values around TL431 are:

R4-   10K-    6,27 V
R5-   3K9-    2,44V
R16- 220R-  0V
R3-  3K3-     7,02V
R7-  470R-   0 V
R8-  1K-      7,92V
R9-  1K-      7,92V.      The Ohm values are from the color Code not measured in place.

I tried to measure the Ohm-Value of R4 with Vin connected. When i put the probe to the legs of R4 the LED begin to light?

Branko

[Branko]

Hi,

I have build a second board with the equal parts (as listed in the .xls File from download for 9V. Only difference TL431. R10 Jumper. Two red LED). I get the same behavior: LED light up for ca. 1 second and go dark. If I measure resistance over R4 with Ohmmeter LED start light again. Minimal different measurement of values. A version for 5 V i build too works well: Vout 4,92 V(not tested with load yet). Basically the same parts only other resistor values (as per .xls file for 5V)

Branko

[peranders]

It seems that I have mixed up with the 19 V version. I'm on a bus right so give me two hours and I can calculate the right values.

[peranders]

Have you selected the 9 V sheet in the excel file? I have different voltages in the same file.