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  1. kellys_eye

    5V LCD brightness has gone down (blank) when 230V AC given to 5V relay ouputs pins

    Show your wiring. I trust you haven't connected the mains neutral to the logic ground.....
  2. kellys_eye

    Loewe TV Chassis Q2500 Startup Failure

    It's either over voltage or over current shut down - either of which requires you to monitor the outputs accordingly - with dummy loads if necessary - to identify the line supply that is causing the issue. Once you know which supply is the problem and for what reason you can move on from there...
  3. kellys_eye

    What is this?

    What's the 'designation' printed on the board beside it? Looks like 'D...' and for the image title presumably D2 in which case it's likely to be a diode. One edge looks to be chamfered which is probably the cathode. Quick test with a meter would reveal all.
  4. kellys_eye

    Circuit boards on a aiwa stereo system

    Look like soldered pin headers to me - no choice other than to desolder them all. Begs the question - why? If there is a fault then you'd trace it whilst it is assembled (but accessible of course).
  5. kellys_eye

    Identifying a chip

    Additionally - the CPU is a 'rare' shrink 64 DIP package limiting the possibilities and with pin 26 being a ground (?) i.e. other end of C6 that appears to be to Vcc of the dud IC, then some investigating into the CPU type might also help...?
  6. kellys_eye

    Identifying a chip

    Looks like Vcc is definitely pin 20 on the damaged chip so doesn't match the datasheet shown.... I'd suspect something simple like a 373 or 244/245. If we can identify the processor it would be simple to discover if the chip is buffering/tri-stating any data lines (which I suspect will be the...
  7. kellys_eye

    Circuit boards on a aiwa stereo system

    .....and? Post pics of your 'problem' and/or links to the manual etc. Too little information.
  8. kellys_eye

    Capacitor selection question

    Less emphasis on all the 'frippery' details is needed. Simply 470μF/16V and 1000μF/25V (in either axial or radial i.e. physically matching the ones you have) will suffice. @davenn suggestion of using 105C versions is good practise and won't make much difference cost-wise. Basically, if it...
  9. kellys_eye

    Switch Identification

    Push button change-over (on/off) I presume? https://www.maplin.co.uk/p/table-light-switch-white-n16eb
  10. kellys_eye

    Martin MX-4 scanner issue

    Change C116 (10μf) - decoupling straight across the μP power lines. Could be transients causing it.
  11. kellys_eye

    Recording and repeating voltages

    DAQ - Digital Acquisition. There are some projects around that offer analog/digital recording onto SD card in multi-channel ways but there are limitations in every system based on sample rate and length of recording although, theoretically, you could do this ad infinitum. In a most basic form...
  12. kellys_eye

    TDS220 repair

  13. kellys_eye

    18650 power supply

    Depends on the quadcopter. Insufficient information.
  14. kellys_eye

    My electromagnetic pulse generator

    What are the 'genuine/realistic' effects of a nuclear-generated EMP? How much more damaging than a decent CME event?
  15. kellys_eye

    Have been given a disassembled Whirlpool grill-microwave oven with missing decals & fuses?

    Without recourse to a test meter...... Grab a few spare fuses! Replace the standard fuse but leave the high voltage fuse out of circuit. Power the unit up and check for all operations. If the main fuse blows again you should disconnect or remove the heating elements and try again (new fuse...
  16. kellys_eye

    Have been given a disassembled Whirlpool grill-microwave oven with missing decals & fuses?

    Show the schematic. Usual problems with such devices are faulty heating elements. An insulation test between mains live-to-earth and neutral-to-earth would be the first check to make (fuses IN, device UNPOWERED).
  17. kellys_eye

    Forum Category Feedback

    I'm not exactly a long time member but I haven't had or seen any particular difficulties with the section design/layout - finding it very user-friendly in its present format. If there are occasional mis-posted questions I'd consider this an inevitability of the subject and, as you state, this...
  18. kellys_eye

    Unknown component

    Brilliant photo.....:rolleyes: the topside location of which is covered by that metal disk..... Still, it is very likely to be a capacitor - you won't measure anything across it using a standard test meter either. It is probably NOT faulty though. The circuit seems to be a simple oscillator...
  19. kellys_eye

    It’s time for consumer Electronics Manufacturers to label their transformers!

    I believe there have been calls for standardisation across the range for such adapters given the plethora of different models, voltages etc. In the scheme of things it is 'nothing' to provide a simple regulation circuit internally of the item to be powered to allow a fair range of input...
  20. kellys_eye

    Desire datasheets for obsolete Signetics FFs, Nor

    Catalog - full details of all devices therein: https://ia801901.us.archive.org/31/items/bitsavers_signeticsdcsUtilLogicIIHandbook_2408731/1968_Signetics_UtilLogicII_Handbook.pdf
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