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  1. Martaine2005

    Radio

    Thanks Dave. I didn’t know that. I also thought the OP was talking about a ‘canned’ variable capacitor. Us MUCH younger guys have no chance with our elders experience:) Martin
  2. Martaine2005

    Hello, can I use adapter with 12v 2A output on a psr433 keyboard

    Yes, as long as the polarity and DC barrel jack fit. The original is 1.5A. Yours is 2A. The keyboard will use/draw only what it requires. IN other words, you can use a 20A providing the voltage is the same (12V) in your case. Also the centre pin is positive on your keyboard. Martin
  3. Martaine2005

    How do I motivate myself to study with 100% focus and concentration during covid lockdown?

    Re-read your post. Then follow it. You know what you should be doing. You also know what you shouldn’t be doing. Martin
  4. Martaine2005

    Automotive Warning light help

    I think you should upload some photos of the PCB. You’ll be surprised at the eagle eyes of some members here. You won’t lose anything by doing so. Martin
  5. Martaine2005

    Small IR gooseneck spot heater?

    You’ll probably find that that heat dissipated in the rest of the ground plane. Which is why the heat plate warms it all over. Besides that, surface tension might actually damage other solder joints due to expansion in one small area. I could be wrong though. I’d be more inclined to whack up the...
  6. Martaine2005

    Tektronix 2214 Storage Oscilloscope can't slide back case to repair it

    I don’t know whether yours has a top and back only but my scope has a back and complete case surrounding it. The chassis slides forward out of the casing. Mine had loose handle/stand ratchets which upon sliding forward, were catching inside. It was very difficult to actually see this so...
  7. Martaine2005

    Seeking virtual tours through various circuits.

    I actually quite like a YouTube channel called “the engineering mindset”. It demonstrates various circuits through animation. The channel link is Martin
  8. Martaine2005

    For Sale: Various Test Equipment

    Me too. (UK). I’m at the beginning of the M4. Literally.. Hammersmith & Fulham. Martin
  9. Martaine2005

    Never seen this before... have you ?

    Yeah, transcription disc typical for radio broadcasts in the 30s, 40s. I think some played from the inside out and were 33 and 78rpm. I had one years ago that wouldn’t fit my turntable, so I threw it like a frisbee . It was amazing and I never found it. Just simply vanished. Martin
  10. Martaine2005

    Repairing PCB damage when surrounding components have been burned

    Use some IPA (isopropyl alcohol) to thoroughly clean the area first. You may then be able to identify the components. Also look for reference designators on the PCB. I doubt you’ll find a schematic as companies don’t hand them out, but it’s worth an internet search. Martin
  11. Martaine2005

    powering a dc motor from ac?

    Typical back of the envelope calculation is 1000μF for each Amp. I have lots of blender motors and Hoover motors, none have smoothing caps just X2 caps. martin
  12. Martaine2005

    Hello everybody......again

    Welcome back Miguel, good to see you on here again. Martin
  13. Martaine2005

    Boosting the Amper and altering the frequency

    The capacitor in link #1 needs a haircut. Martin
  14. Martaine2005

    old kitchen fan doesn't work

    Very difficult without another to compare it with. No pictures on google images either. 5, 6 and 7 look promising, but does the spring fit snugly in 5?. Where are the blades or fan?. Does it have three holes or does the motor housing have three holes for screws?. 3 is either a bushing (bearing)...
  15. Martaine2005

    How do you get homework help when you reach master's level of very higher level of education?

    Perhaps your questions weren’t asked properly. Starting a thread topic with “high level education” and “not many people study this” makes others think you’re a know it all. Start by saying “I don’t understand this” or “can somebody please explain this”. Better still “I’m studying this and get no...
  16. Martaine2005

    IR sensing human presence

    How are you expecting this to detect? Specs say “max 300mm detection”. I would think that’s a little optimistic, maybe 150mm. Also, where is the module located? In a very bright room, it may not work at all. Try covering the LED a little to block day light. Then, if still not working as desired...
  17. Martaine2005

    IR sensing human presence

    The link states “for human sensing, use a PIR sensor”. Martin
  18. Martaine2005

    Strange battery behaviour in portable radio?

    Massive difference. 6mA vs 111mA 30mA vs 200mA. Perhaps that’s why the Roberts only has two AAs and the other needs four!. Quite a hungry little radio! Martin
  19. Martaine2005

    Transformer voltage output higher than expected

    Measure the voltage with a load. Martin
  20. Martaine2005

    Is this MOSFET right for this voltage?

    I don’t know where you get your info. They are limited to 15.5 mph and lower in certain places. You have to have a valid driving licence to hire the trial scheme scooters of which, the operator pays insurance. I will gladly eat my words if I’m wrong. Martin
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