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  1. kellys_eye

    Whirlpool oven timer problem

    The two red arrows should read open circuit unless the element is ON in which case it will read as a short circuit.
  2. kellys_eye

    Samsung HT-E8200 Power Supply

    Are you measuring correctly? The '32V' you measure should be more like 320V.
  3. kellys_eye

    Modern Day Use for Old Electronics vs New Electronics. Is it Realistic & Practical?

    I don't know everything - just the stuff I need to know.
  4. kellys_eye

    Boardgame wiring question......

    You can do this with a miniature mains transformer wired backwards and use the back emf to give someone a (safe) zap.
  5. kellys_eye

    Can't Identify Components in Old Guitar Amplifier

    Cathode resistors commonly fail due to capacitor failure - change the capacitors first. Then change the obviously overheated resistors. Unless the remaining resistors read well outside their tolerance I'd leave them alone.
  6. kellys_eye

    Circuit for switching speaker and LED

    What kind of audio levels are we talking? Anything 'domestic' would easily be handled by standard toggle/rocker switches rated at 125V/3A. The wiring arrangement you show is fine - no fuse required for the LED as the USB-delivered 5V is 'protected'.
  7. kellys_eye

    Q954 unable to find data sheet

    That device will be a DIAC.
  8. kellys_eye

    Modern Day Use for Old Electronics vs New Electronics. Is it Realistic & Practical?

    For prototyping purposes there's nothing simpler than standard thru-hole components. Same might apply for an application that is a one-off construction that isn't constricted by space requirements. It's only when you get to production that sub-miniaturisation comes into its own both for space...
  9. kellys_eye

    V510 inspection station

    You say it lacks a 'comprehensive component library'. Do we therefore take it as read that there is some sort of library there now? If this is the case it will reside in its own file/folder and an inspection of the contents may give some insight as to how such a component is designated and...
  10. kellys_eye

    Can't Identify Components in Old Guitar Amplifier

    They both look like resistors to me. The red one certainly is. The value is read from the colours - body, tip, spot. So body red (=2), tip (orange?) =3 and spot (brown?) = x10 multiplier. Value is therefore 230 ohms. The colours may have changed over the years so the above is just a guess...
  11. kellys_eye

    How to disable DT9205A auto power off?

    The LM358 is a dual comparator so will provide (potentially) the functionality for ONE of the services shown in the schematic. If the meter can actually measure capacitance (does it?) then that function alone requires four comparators. Also, given that the unit requires the AC-to-DC converter...
  12. kellys_eye

    V510 inspection station

    I take it you've approached the OEM for assistance? Do you have all the user manuals etc? Does the system allow for 'learning'? In which case you'd have no choice but to show it parts and let it do its thing.
  13. kellys_eye

    How to disable DT9205A auto power off?

    The schematic shown shows IC2 and IC3 both to be quad comparators that are only usually available in 14- or 16-pin packages. Given there are TWO such devices on the schematic and the board only has ONE 14-pin device (marked as a 14-pin logic gate 74HC04) the schematic clearly is not what you...
  14. kellys_eye

    How to disable DT9205A auto power off?

    My advice is based on the assumption that the schematic and board overlay are correct. Given the timing circuit notes that the timing components are R63/C16 and the highest numerical resistor designation I can see on the actual board is only R53 I don't know where to go from here..... Are...
  15. kellys_eye

    Q954 unable to find data sheet

    Good spot - suggest something like a C106 to replace it.
  16. kellys_eye

    Hitachi 57F710E Power Issue

    Bad move. If there was a fault prior to the IC then that fault remains and could have destroyed the IC again. Given that the DC voltage is (was) incorrect coming from the BR you should have sorted that issue first. Proving my point..... If the switching IC was working you'd measure ~170V DC...
  17. kellys_eye

    Q954 unable to find data sheet

    That looks like an old 'lockfit' type of transistor - inevitably an NPN but of standard enough parameters that practically any NPN (like the ubiquitous BC548) would work in its place. However if that's a 'mini heatsink' type thingy poking out the back of it then use a suppliers parametric...
  18. kellys_eye

    How to disable DT9205A auto power off?

    Disabling the auto-off function is entirely your choice but it would be far better to simply lengthen it to the point at which you are happy - changing the capacitor C16 from 47uF to 470uF would extend the on time by a factor of 10x
  19. kellys_eye

    UT61E multimeter AC measurement issue

    If there are no obviously blown parts then try adjusting (note the position of first and ensure you can replace them to their original settings if you have to) VR2 or VR4. Maybe just give them a 'wiggle' in case it's down to dirty carbon tracks.
  20. kellys_eye

    How to disable DT9205A auto power off?

    Why did you label it as C19 then? According to the 'actual' schematic it's C16. To bypass it entirely you need to short the collector-emitter of Q2.
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