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lysium

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Everything posted by lysium

  1. i see.... right now the LED is light up after i change the capacitor but without U2 and U1 in place, still looking in local store here.
  2. after browsing old posting. i found that picmaster pcb drawing has a fault on C10 or C3 if using audioguru schematic it is + and - of the capacitor is backward in the pcb. and i found mine was backward and it is now shorted maybe this is the cause of the U1 and u2 blew?
  3. ok... i have to wait the new op-amp from digikey. will inform you later. btw can i use opa445? i have few in the drawer. thanks
  4. what should i do? when P2 set to 3.8V the ZD 10V and op-amp is impossible to touch i think it will blow too if i set to long.
  5. hi all specially Audioguru, i build with mc34071, 24VAC transformer and picmaster PCB layout... yesterday i blew two op-amp U1 and U2. i trace from u3 when i turn P2 until 3.4-4.0V on R18 u3 and ZD 10V become very hot. and i think when those op amp blew i set the P2 more than 3.4V.... what's wrong? regards, ali
  6. just replace R2 with higher watt, 5W and C2 with branded one still -2.1V with full load. output still stuck at 28.5V. R7 because i have difficulties to find one so i use 4 1Ω parallel is it problem? thanks
  7. without load (remove all ICs) it is -5.6V. with load (all component) except Q1, R13, R14 is -2.1V thanks
  8. so i just remove the Q1, R13, R14, R15, D10 correct? is it in D7 i have to measure the -5.6V? thank's
  9. Hi audioguru, just finished soldering all the component using old schematic + old pcb layout with OPA445 and 25Vac 6.25A toroid. but there is a problem the output can not be adjust? and the U1 is slightly hotter than the others. do you have test point what the voltage should be at that point so i can check it. and R2 and R3 is really hot around 40-60 celsius is this normal? thanks
  10. hi audioguru, i have opa445 on hand right now, so which schematic should i use? thanks,
  11. hi all, is it possible to use LT1491 for the op-amp? coz i have few on my drawer thanks,
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