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
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
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.
Hi,
R10 jumper. Tin blobs are in place. R8/R9 1K.
Moved R11 (47R) to R12. R11 open
Branko
Can you measure across R8 and R9?
R9 0V; R8 0V
Branko
Check R8 and it's connection to the output. R3 is connected to R8 and the LM431 seems to be working.
Hi,
I will check after noon when I am back home. I use a TL431 not a LM431. Is that a problem?
thx
Branko
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.
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
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.
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
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
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.
Have you selected the 9 V sheet in the excel file? I have different voltages in the same file.
Hi,
yes I used the right sheets for 9V and for 5V (latest files newly downloade)
Branko
R4 10k
R5 12k
= 8.947 V
Add R6 820k
= 9.006 V
Try this.
Hi,
after adding R5 12K and R6 820K i get exactly 9,06 V :-D :-D :-D
Thnk you.
For my 5V board I get 4,91 V out. How would I ge closer to 5V?
Branko
It has no importance of having exactly 5 volts but it may feel better. Can you tell me what you have as R4, R5 and R6? Measure also the voltage across R5. I'll calculate this for you.
Hi,
as per your .xls file there a no R5 or R6 only jumper for R4.
Branko
5 volts
You have 2.455 V reference
Alt 1:
R4 47R
R5 2k7
Alt 2:
27k in parallel over R9, mount at solderside.