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  1. kellys_eye

    Phillips TV just died 42PUS7809/12

    If you test D501 it will likely show a short circuit but that will probably have been as a result of U501 going faulty too. Possibly other issues as well but those would be the two starting places. It might be easier and more cost-effective to seek a replacement board.
  2. kellys_eye

    DC step-up booster/converter

    You don't. The circuitry will take whatever current it needs and work just perfectly. Mind you, that's a bit of a waste of resources given the fans are running at 1/300th the capacity of the boost converter!
  3. kellys_eye

    What is the value of resistor?

    3.2 ohms
  4. kellys_eye

    Yamaha TSR-5810 No Power, No Standby Light, No Relay Click

    Chips fail - the FET inside those switching IC's is under quite a lot of stress so is the first thing to go dud and commonly so. They are NOT readily available devices but easily changed - standard soldering techniques - if you can find one. Here's one possible place...
  5. kellys_eye

    Yamaha TSR-5810 No Power, No Standby Light, No Relay Click

    Nope - the pink voltages have country-specific values, J-Japan, U-USA, G-United Kingdom etc. If you're in the USA it should read around 165V. 500V is Waaaaayyy too high! Sure you're using the meter correctly and/or that it's working correctly? The beep you get when testing that diode is...
  6. kellys_eye

    DC Motor spinning with battery, but not after DAC

    The key issue is WHY you're trying to control motor speed this way. It's almost 'impossible' without some form of feedback and the motor will not maintain a steady speed using this method. Getting it going from standstill will be a 'hit and miss' affair. As mentioned above, you really should...
  7. kellys_eye

    Yamaha TSR-5810 No Power, No Standby Light, No Relay Click

    What makes you think it has a short? It will conduct from one pin to two others but that depends on how you're measuring it too. Have you done the 'basic' tests first i.e. is the fuse ok? If so, measure the DC across C5419 - it will be 'lethal' (if you touch it) so take care. The DC voltage...
  8. kellys_eye

    Trace and connection repair help (Atari centepede PCB)

    (my added bold) LOL! Oh so true!
  9. kellys_eye

    CNC PCB Plotter

    You can use 'anything' to drive a CNC but why you'd want to use something that isn't already common place (in that particular form) is beyond understanding. You're talking about 're-inventing the wheel' when there are multiple working examples using other devices already in existence.
  10. kellys_eye

    Help With automotive gauge cluster

    Linear voltage regulators are as their description - usually converting one DC voltage level to another i.e. 12V down to 5V as an example. They are very common and readily available although a quick test of their input and output voltages will show if they are working as intended. As to the...
  11. kellys_eye

    treble control centre frequency

    C1, C2, R2 and R3 form the active part of the filter and set the filter frequency. The values need to be changed to cater for the frequency you want according to a formula that you will find amongst these tutorials on filters (very useful site for learning)...
  12. kellys_eye

    Help with 5v led dimmer Battery/mains

    Monitor the battery voltage as you adjust the brightness and see if it falls off as the brightness increases. There may be a minimum voltage level it works at.
  13. kellys_eye

    Help with 5v led dimmer Battery/mains

    What's the spec of the dimmer? It may be cutting off due to too high a current draw.
  14. kellys_eye

    Help With automotive gauge cluster

    The chips will have codes on them that are usually discoverable at various datasheet sites like www.alldatasheet.com using their search engine. I'd hazard a guess (since I can't read the numbers) that they are stepper drivers intended to drive the pointers on the dials which themselves are...
  15. kellys_eye

    Trace and connection repair help (Atari centepede PCB)

    As tempting as it is to repair the actual track it's pretty much a forlorn exercise as no one is (probably) ever going to see any hard work you put into making it look as original as it ever was. Tracing the broken track back/forward to the next nearest component 'land' and hard wiring a link...
  16. kellys_eye

    2 appliances 1 switch

    Not the voltage - the wattage ( or the amperage). A typical washing machine may, when heating water, consume 2kW (or more). A dryer can run to 3kW. Add in a dish washer may be around 1.5kW. Total for BOTH operating would be 4.5kW and, with allowance for 'extras' round up to 5kW. 5kW at 120V...
  17. kellys_eye

    2 appliances 1 switch

    What are the equipment power consumption ratings? The total consumption (amperage) should be LESS than the switch rating PLUS the circuit wiring (to the outlet) should be capable of taking the load.
  18. kellys_eye

    Dual output PS 12/24v missing 12v output

    What are the current rating of the outputs? i.e. 12V and 24V? Does the main switching transformer deliver the 'base' 24V and is the 12V derived by a simple regulator on the 24V line? or are they both separately derived sources i.e. from individual secondary windings on the switching transformer?
  19. kellys_eye

    Uniden Atlantis 250 Handheld 2-way VHF radio --- Does not receive / no audio for incoming

    The PLL is only one possible cause of a fault - you'd have to dismantle the set and take the appropriate measurements to see if any of them actually are 'unlocked'. If you've looked up how a PLL works then you should appreciate the various 'boxes' that form the loop and a failure in any one...
  20. kellys_eye

    Uniden Atlantis 250 Handheld 2-way VHF radio --- Does not receive / no audio for incoming

    If you have another known, working, signal source you can of course prove an issue with the receive section. It does appear to be the case however this could also be due to an unlocked PLL in the receiver since you haven't got the 'tone' that signifies a correct channel change. If you don't...
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