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  1. R

    0-30 Vdc Stabilized Power Supply

    D10 was shorted. Many thanks goes to audioguru, the man, who cares. Respect. Now i wont connect ammeter between emitter of Q4 and output. I will better use voltmeter to measure across R7. I did build one based on 7107 and it works fine (as a panel meter for this project). Now i have one more...
  2. R

    0-30 Vdc Stabilized Power Supply

    pin6 U3  31v pin3 U2  8v pin6 U2 3v base q4 0.5v base q2 0.7v all measurements with the load of 20 ohm without load, pin6 u2 is 25v
  3. R

    0-30 Vdc Stabilized Power Supply

    Measured Q2 - seems to be ok.
  4. R

    0-30 Vdc Stabilized Power Supply

    Tried with 20 ohm. I did set voltage pot to 25v and current pot to half-way. When i connect the load, voltage drops to 0.6v and current is about 0.03-0.04 amps. Current and voltage regulation pots do nothing then.
  5. R

    0-30 Vdc Stabilized Power Supply

    With the load of 1 ohm voltage stays at 0, it can not be regulated. Current pot is in the middle. LED is off.  Voltage pot does not change anything. Current pot also does not change anything. There is no current regulation. Ammeter in the series with the load (1ohm) shows 0.03amps independent...
  6. R

    0-30 Vdc Stabilized Power Supply

    Here are the voltages measured at U3 with the current pot half way, load on (680ohm): pins: 1 - -5.6 2 - 0v 3 - 1.48v (can be regulated with the current pot 0-3v) 4 - -5.6v 5  - -5.6v 6 - 31v 7 - 31,8v
  7. R

    0-30 Vdc Stabilized Power Supply

    With the load of 1 ohm voltage stays at 0, it can not be regulated. Current pot is in the middle. LED is off. With the load of 680 ohm voltage can be increased to 17.6v and then stops, but LED is still off. Current pot is in the middle. LED goes on only when current pot is completely down. Both...
  8. R

    0-30 Vdc Stabilized Power Supply

    Hi audioguru. Thank you very much for your reply. Fuse is inserted straight after secondary winding before rectifier in order to protect the winding. It had a value of 2.5 amps and before everything was working excellent. I do have a 24v transformer and for building this psu i used your 24v mod...
  9. R

    0-30 Vdc Stabilized Power Supply

    And here what i measured: pin4 (both) -5.65v; pin6 u1 +11.32v; pin6 u2 0~27v. LED goes on when there is a load and current pot is to minimum. Both Q4 seem to be ok.
  10. R

    0-30 Vdc Stabilized Power Supply

    Finally i managed to put it all together. Everything was working fine. I connected 1 ohm resistor to the output and measured up to 2.5 amps through it. Voltage and current regulation was excellent. Then i decided to insert ammeter between emitter of Q4 and output, as audioguru suggested. And i...
  11. R

    0-30 Vdc Stabilized Power Supply

    OK, found the problem, now everything seems to be working. Q3 was bad somehow and had to be replaced. Thanx, audioguru! ;)
  12. R

    0-30 Vdc Stabilized Power Supply

    Well, the problem is that the LED is constantly on!
  13. R

    0-30 Vdc Stabilized Power Supply

    Just finished building mine!! But not without a problem.  :'( Voltage regulation works fine, but current LED stays on all the time ???
  14. R

    0-30 Vdc Stabilized Power Supply

    I just sampled some TC7107 from Microchip  ;) I have some spare LED 7-segment displays, so i will try them first. But i still like the idea with PIC  8)
  15. R

    0-30 Vdc Stabilized Power Supply

    Yes, thank you, audioguru, but i already saw it. It is based on a chip from Atmel plus it is a surface mount version of chip, which will be difficult to mount for beginners. I work with PICs and program in PicBasic. There is no sourse code for development and in general schematics and project...
  16. R

    0-30 Vdc Stabilized Power Supply

    Went for a walk and had an idea. Surely i want to have an volt/ammeter built in. Digital one. One way is to buy standard models such as 7021 based. I thought of making one myself. I have spare PIC16F870 which has four 10 bit A/D converters on board. And i just bougt two 2x16 LCD screens on ebay...
  17. R

    0-30 Vdc Stabilized Power Supply

    So far, so good! Many thanx again. Off i go to produce PCB and collect the rest of the parts. BTW, Eagle PCB , posted on previous pages, does not work :( My Eagle Light says it was made with some faulty version of Eagle ;) "Load error 283... blah blah blah.."
  18. R

    0-30 Vdc Stabilized Power Supply

    And here comes Audioguru!
  19. R

    0-30 Vdc Stabilized Power Supply

    Hi everyone! I just finished reading this threads about 0-30v power supply (both original and 5 amp mod). About 100 pages... 2 days time.. Wow So, i desided to build it, namely the
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