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  1. kellys_eye

    What do I need?

    Can't say I've ever seen one of decent enough spec to justify it's purchase over a 'real' 'scope. If all you want to scope are audio signals you could do that with a $15 Chinese scope kit!
  2. kellys_eye

    Can a Chopper Realistically Be Built

    nor does it when talking about a sedan or coupe..... but you get my drift?
  3. kellys_eye

    Denon DRA-335R receiver - Left speaker channel not working on speakers A/B.

    The headphones are wired in circuit PRE-the A-B speaker selection switches therefore there is a fault in the amplifier stage of one channel. Page 14 of the technical manual shows how and where to measure the amplifier bias current and by following those instructions you may be able to isolate...
  4. kellys_eye

    Microcontroller replaceable?

    whilst I agree, the current in the 'top' transistor is an order of magnitude (or two) less than that of the 'bottom' one and, imho, less potential for failure.
  5. kellys_eye

    Wiring LEDs to Corresponding Switches?

    It's the same process as wiring one LED to a switch. Power supply, switch, resistor, LED. Repeat ad-nauseum. Power supply is whatever voltage you require and (xLED multiplied by its operating current - usually 20mA) rated. i.e. for 100 LEDs running at 20mA you will need (100 x 0.02A) = 2 amp...
  6. kellys_eye

    Can a Chopper Realistically Be Built

    The cost and effort involved in building one would exceed the cost of purchasing a used (good) one. This is often a problem faced when trying to circumvent the facts of 'mass production'.
  7. kellys_eye

    What do I need?

    My in-laws wanted to fit those LED filament lamps all over their property and purchased all the lamps from a local supplier at some extortionate cost. I explained that I could get them direct from China for 1/5th the cost but they insisted that the local suppler, despite their high price, had a...
  8. kellys_eye

    Microcontroller replaceable?

    What tests did you make to come to that conclusion? Processors are usually 'good-or-dead' though this isn't always true! The 2803's generally offer protection between input and output (any fault has to feed back through a darlington pair) so any fault is unlikely to feed back to the processor...
  9. kellys_eye

    What do I need?

    The consumer electronics industry is plagued by two problems - one is IPR (intellectual property rights) where no one is prepared to tell anyone anything, or reveal any technical data they don't have (want) to. Secondly (and it ties in with the first really) is their 'need' for built-in...
  10. kellys_eye

    Denon DRA-335R receiver - Left speaker channel not working on speakers A/B.

    Do both channels work in any other mode? We need to isolate whether the fault is in one channel of the (stereo) FM receiver or in the amplifier itself. Do you have headphones (and a socket to use them in)? Try them if you have. It is quite likely that one channel is defective - a common...
  11. kellys_eye

    Where to find scrap electronics?

    I've been fortunate recently with 'finds' like transistor radios (pre 1970's) that are ripe for restoration which I find are far too nice to scrap for parts. The restoration process is very satisfying too and it's possible to make a healthy profit if you know what to look for and what to do...
  12. kellys_eye

    Replace power MOSFET in subwoofer plate amp, Sledge STA-1000D

    Many MOSFET switching devices have HUGE ratings for little price - a 600V device with 30A rating in a TO247 package shouldn't be difficult to find.... or something like it. Sites like this: http://category.alldatasheet.com/index.jsp?sSearchword=MOSFET%2030A%20TO247 have search facilities to...
  13. kellys_eye

    Where to find scrap electronics?

    Many of the charity shops in the UK will refuse electrical/electronic items due to the necessity for PAT testing..... AFAIAA you aren't allow to sell items without such these days.
  14. kellys_eye

    E liquid stirring plate

    Check the label on the fan - it should show the power consumption (i.e. 12V @800mA or whatever). Sum the two CURRENTS as shown and then purchase as power pack that has at LEAST the sum total current - more is ok, less is not recommended. Wire the fans in parallel. Their free-running speed...
  15. kellys_eye

    Denon DRA-335R receiver - Left speaker channel not working on speakers A/B.

    ...as per @shrtrnd (above) the fault may be very easily rectified however there is always the possibility that a 'finger fault' may be the cause. Whilst my first instinct is that the fault is 'genuine' there are protocols to follow in any fault finding process and the basics, that may sound...
  16. kellys_eye

    E liquid stirring plate

    A 12V wall wart (power pack) should easily deliver the required current. Simple toggle switches for on/off or, if you are feeling ambitious, a PWM speed controller could be added.
  17. kellys_eye

    Denon DRA-335R receiver - Left speaker channel not working on speakers A/B.

    Operating manual http://www2.aerne.com/Public/dok-sw.nsf/0c6187bc750a16fcc1256e3c005a9740/ec59a493e30f927bc1256dff007842ca/$FILE/DRA435_335.pdf Servicing manual https://www.manualslib.com/download/720679/Denon-Dra-435r.html Check you're operating the set correctly as per the user manual and...
  18. kellys_eye

    Converting UPS plug from NEMA 5-15/20R to 5-15P

    According to Wiki the two just differ by design, not function, so you can change them as required: https://en.wikipedia.org/wiki/NEMA_connector#NEMA_5
  19. kellys_eye

    Help finding a display

    Try again - you're lacking in information........ How big? There are the generic 7-segment LEDs that come in all sizes up to around 5- or 6-inches in height and dot-matrix versions of similar size (perhaps a little smaller maximum size). Or there are LCD's in dot-matrix and alphanumeric...
  20. kellys_eye

    I need help determinig correct voltage.

    Seems as if the LEDs have some form of current limiting and/or control on the lower circuit board. Do you have any idea what the original supply voltage to the equipment was? I suspect there will be a voltage regulator in there somewhere as the LEDs 'look' to be lit appropriately - just...
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