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  1. (*steve*)

    A Welcome to EP For AudioGuru

    Perfectly reasonable. But we prefer if you back up criticism with helpful advice.
  2. (*steve*)

    Component equivalent

    Is the original surface mount? It is very unlikely that the transistor was the primary fault. If the fault remains, a replacement will likely suffer the same fate. In this case, having some spares is not a bad thing :)
  3. (*steve*)

    RT8059 step-down DC/DC converter - can't get it to be stable, annyone with experience?

    Perhaps you can post the schematic, links to the datasheet, and give us some idea of the way the output voltage varies (and especially the timescale). It would be useful to know how you are measuring the output voltage -- a multimeter, or an oscilloscope?
  4. (*steve*)

    Where can I buy a high voltage transformer

    In general you can get very high voltages out of a fly back transformer. Fly back describes mostly the method of operation, but there are many transformers designed specifically for this mode of operation. These were once common in TVs where they were used to create the several to tens of...
  5. (*steve*)

    Design filtering capacitor

    A simple rule of thumb is that 1000uF per amp of current from a full wave rectified ac source will give you about 5V of ripple. In this case there is 3300uF and if the max load current is 1A, then the ripple will be about 1.5V. If you have a 12V transformer, and your reg requires 2.5V...
  6. (*steve*)

    NPN transistor as switch for LED problem

    Oh, and a base resistor of 100 ohms! If taken to 12V then that's over 100mA of base current. I hope your transistor can handle that. Its also more than that used by the LED!
  7. (*steve*)

    Having trouble identifying a diode needed for a repair.

    Those diodes are all in parallel across two of the spade terminals. They could be reverse voltage protection. Did anything get connected incorrectly, even for just an instant?
  8. (*steve*)

    Help With Basic Seven Segment Display Counter Circuit

    Best to test it with a multimeter. TTL has quite a weak pull-up, so checking with a LED is not reliable.
  9. (*steve*)

    impose current ceiling

    You could also place a relay across a solar panel. when the current exceeds a certain amount, short out a panel (or another panel). When it drops below some value un-short the panel. Hop's idea, combined with an inductor, capacitor, and diode becomes a buck SMPS.
  10. (*steve*)

    NPN transistor as switch for LED problem

    It depends on the leakage current. If it is 0.1 mA and you don't want more than 1V across the LED, then 10k would be the value I'd start with. If you are pulling the base low with a similar value resistor then a leakage of 0.1mA is pretty huge.
  11. (*steve*)

    LEDs in parallel don't consume sum of individual currents??

    But to be fair, my guess was a lucky one because if I had done the calculations before I made it, I may not have risked the embarrassment :) I think this has been an important lesson in how even a small resistance can have a dramatic and largely unexpected impact on the current through a LED...
  12. (*steve*)

    Part required or is another suitable

    Ok, then in the post where you said there was continuity between the red arrows and pin 6, did you measure this on the board with the chip removed, or the other one?
  13. (*steve*)

    Cheapest way to get data from multiple(100s) of sensors?

    An additional bit of weirdness with internal reflections from a glass surface means that in some cases you might sense LESS reflected light when something is placed on top of the glass sheet. And on the question about speed. Given I suggested you could easily read the array 500 times per...
  14. (*steve*)

    CRT tv help please?

    Wow, I cant even begin to think what would cause that. Do you have access to other controllers and/or other consoles to check to see if they suffer from the same problem?
  15. (*steve*)

    LEDs in parallel don't consume sum of individual currents??

    And while you're answering Chris' request for a schematic and a photo (which I'm sure the rest of us would like for confirmation), can you also tell us the make /model of multimeter and tell us what range it was switched to when making the measurements. A photo of it would be good too.
  16. (*steve*)

    Part required or is another suitable

    Is there still a pad there? The photos make it look like there are none except for pins 7, and 10 to 16.
  17. (*steve*)

    Part required or is another suitable

    On the other unit, can you confirm there is continuity between pin 6 and the via at the end of the trace coming from under the end of the chip between pins 8 and 9?
  18. (*steve*)

    Part required or is another suitable

    You have ripped a number of pads from the board when you removed the old chip. Whilst it might be arguable that some of those pads were not there in the first place, it is undeniable that the gnd pin (8) would have had a pad. Also the trace running under the chip would have lead to a pad. To...
  19. (*steve*)

    how to discharge battery

    For capacity testing, a constant current load will allow you to measure in mAh, and a constant power load will allow you to measure in in Wh. A constant power load is rather more complex and it wouldn't be my first recommendation. In either case you need to specify an end point. For...
  20. (*steve*)

    CRT tv help please?

    You're saying that the button functions on the game controller change when you connect the video console to a different type of TV?
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