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  1. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Will be ordering some new 2N3055's But my old 3055's confuse me: Using an analogue MM black probe on common, red on base I get no connectivity. Swing the probes around and I get connectivity. Using DMM I get OL on meter both ways:confused: Is the high voltage of the analogue meter causing a...
  2. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Thank you Audioguru thank you. The 19.3 V was measured on pin 6. The 41V measured on the power supplies outputs. Thanks for the additional components to check on the -1.3V. That has been irritating me. Have checked 2xD7 already for polarity switching. How easy is it to blow the BD139 and the...
  3. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Pin 4 of U3 goes to 0.3V when U3 removed Voltage of pin 6 of U2 unchanged as Voltage pot turned. Output voltage constant at 41.6 V Oh, and led on again.
  4. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Voltages: (V) BD139 E 27 C 40 B 17 Q5 (2N3055) B 27 E 39 C 40 Q4 (2N3055) B 26 E 39 C 40
  5. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Have done a lot of checking and fixing. Led still coming on. OPamps getting warm but U3 not gettting as wickedly hot as previous bur still hot U1 readings still the same so not reproduced U2: 1. 0V 2. 0V 3. 3.6V 4. 0V 5. 0.1V 6. 19.3V 7. 41V 8. 0V U3(overheating?) 1. 4.7V 2. 3.3V 3. 3V 4...
  6. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Yeah, irritating, have to keep referring to paulv's numbered layout printout. But making progress: Have now sorted pin 4 on U3 and U2 and think I have found an easy way to move D11 endpoint from R7 line to the line above. Then we might start getting somewhere
  7. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Thanks for the help Audioguru. Your insight into this just staggering. It took me a day to figure this out. Making that change has sorted the overheating U3, also switched off the led coming on when powering up. I am still working my way through your list of problems. What i now want to sort...
  8. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Audioguru: Thank you for your valuable comments. Busy working my way through them and checking stuff. Opamps are TLE2141IPE4
  9. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Readings on the opamps: These readings taken with the disconnects/connects still in place U1: 1. 1.2V 2. 5.6V 3. 5.6V 4. 0V 5. 0.6V 6. 11.2V 7. 41V 8. 0V U2: 1. 0.4V 2. 3.7V 3. 37.4V 4. 4.4V 5. 4.5V 6. 4.8V 7. 41V 8. 0V U3(overheating) 1. 3.6V 2. 16V 3. 11.3V 4. 4.3V 5. 3.6V 6. 41V 7. 41V 8...
  10. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    This is the only thread I have about this power supply. What other threads are there? The only numbered one I have found kindly done by paulv: Ok, so now I know you are talking about the front panel voltage pot . With the disconnect/connects done output voltage sits at around 40V and...
  11. bushtech

    Can anyone ID this transformer?

    Those 2 green jobs look suspiciously like 18650's stuck in a time warp
  12. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Audioguru, I feel so bad about wasting your time with this. My apologies. Pin 7 of U3 involves Di3 where I used paulv's connection and track breaks: Not sure how all that connects with pin 7 Pin 7 of U3 is sitting at approx 40V! Apologies I now understand how to connect R12/C6 and pin 6 of...
  13. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Lifted the anode leg of D9 and a leg each on R12 and C6. Measuring the voltage on cathode leg of D9 = 5.2V Voltage between R6/C12 and pin 6 of U2 = 35V. Voltage does not change when adjusting voltage on panel pot or RV2 Sigh!
  14. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Pretty sure D13 connected correctly: But I'm seeing 30 V between it and Q3 Thanks for that Audioguru. Will get on it
  15. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Sorry Audioguru, yes pcb from banggood so all original unchanged parts are those that came with the kit. Yep something gone pear shaped. BD139: e: 39.2V c: 41.6V b: 39.3V Tried to get these as accurate as possible. Have to be quick. Tried to wait until readings stabilised The 10V 1W zener...
  16. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    The 2N3055's could be suspect. I found them in a lot of electronics spares I was given, they look unused but they are at least 20 years old
  17. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    I have now turned all pots down. Dummy load still connected. Pinouts on BD 139 checked and correct. R20 is 10k. Can't see any shorts at U3 and D9. 99% of components come from Mantech here in SA including the TLE2141P's which I can see they imported from Mexico. The Voltage I was measuring on...
  18. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Still have a 7.5kΩ dummy load attached. Pots not set yet. Will check the rest, thanks Audioguru
  19. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Got my little digital led meter VA meter connected and Voltage not working but the ammeter shows 5.6A. If it's correct............
  20. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    I suspect these are problematic: U3: pin 2 = 3.8V pin 3 = 3.8V
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