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  1. KJ6EAD

    Setting up an LED moonlight system

    The switch mode regulated supplies are usually quite accurate and more efficient than the heavy electromagnetic types. I'd just made the schematic with 68Ω before I recalculated the correct value so you got that right. E24 refers to a system of standard preferred values...
  2. KJ6EAD

    Setting up an LED moonlight system

    I would use three LM317LZ linear voltage regulators as constant current regulators for 3 strings of 3 LEDs (2 of blue and 1 of red). Add whatever switches you like. A 62Ω (an E24 value) resistor will hold the current at 20mA. You can use any DC power supply from 12.6 to 37V. If your supply...
  3. KJ6EAD

    How to test capacitors without desoldering/Synth repair

    There's not much more I can do from here. If you have -12V coming in on the connector and you don't have -5V coming out of the regulator, there's a problem somewhere in the few circuit components along that path. I did notice that there's a couple of resistors (R142 & R143) on the schematic near...
  4. KJ6EAD

    How to test capacitors without desoldering/Synth repair

    Main PCB schematic (KLM-1589), lower left corner, IC52 and IC53. There's a layout diagram in the manual that should help you find it on the PCB but it's easier probably to simply follow the cabling from CN4B.
  5. KJ6EAD

    can anyone suggest a low voltage plug solution for our sculpture project?

    You've created an impossible specification. You can have it good, fast or cheap but not all three.
  6. KJ6EAD

    How to test capacitors without desoldering/Synth repair

    There are two other voltage regulators on the main PCB that develop +5 and -5 from +12 and -12. Can you find and check those outputs?
  7. KJ6EAD

    How to test capacitors without desoldering/Synth repair

    With the power off, disconnect the loads (CN4B, CN7A and CN16A) from the power supply board then power on and test for the DC voltages shown below. Although the grounds are shown assigned to their respective supply voltage, all are common to each other. CN4B (Main PCB power) 1 +5V 2 +5V 3 5V...
  8. KJ6EAD

    DPDT push buttton switch

    He just needs an ORCAD spice model for his switch, but he hasn't specified what switch (brand and model) and will probably have to create it himself. http://lmgtfy.com/?q=orcad+spice+models
  9. KJ6EAD

    How to test capacitors without desoldering/Synth repair

    That's nice, but I can't see it. Get a clue. It's a good idea to take the photo straight on and with the legending on the board readable right side up. I want to help you but you're not doing your part yet.
  10. KJ6EAD

    How to test capacitors without desoldering/Synth repair

    That sounds (pun) like a thermal intermittent in the power supply section which could be caused by an electrolytic capacitor or something else. You should rule out flaky connections and solder joints by poking around with an insulated probe (stick) with the power on before you go after the...
  11. KJ6EAD

    28 gauge?

    Jameco Electronics has six colors for $7/100'...
  12. KJ6EAD

    Very Basic FM radio help

    You have to use a switch to select or bypass the attenuator so it doesn't affect the weaker stations. On many small portable radios, this switch has two positions labeled DX (distant) and local.
  13. KJ6EAD

    Very Basic FM radio help

    You can add a simple resistive T or pi attenuator for local stations.
  14. KJ6EAD

    gps and audio

    GPS is a receive only technology. There are some systems and protocols that link a GPS receiver to a transmitter to send location data, notably the Motorola Rhino FRS/GMRS radios and the automatic position reporting system (APRS) packet system used by amateur radio enthusiasts (hams). Of course...
  15. KJ6EAD

    Very Basic FM radio help

    A folded dipole antenna made from 300Ω twin lead similar to the dipole that Duke described how to make can also be purchased cheaply or found with old stereo systems as they're often included with them. They look like this rolled up. There's another method using just the coaxial cable with no...
  16. KJ6EAD

    Radio comms

    Goats on the air. Ham radio fun. http://www.youtube.com/user/goathiker
  17. KJ6EAD

    Solder Help!!!! PLEASE!!!

    Two of my favorite soldering technique videos below. The YouTube channels CuriousInventor, SolderingGeek and jkgamm041 contain many more. How and why to solder correctly. http://www.youtube.com/user/CuriousInventor#p/u/41/I_NU2ruzyc4 Surface mount soldering 101...
  18. KJ6EAD

    Where to buy PICkit2 in India?

    The listing above is for a clone, not the official PICkit2. You might also take a look at the Microchip distributors in India. http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1975&country=India
  19. KJ6EAD

    headphone repair

    The impedance rating and wattage of the speakers, the physical dimensions, shape and frequency response would be the main criteria in selecting a replacement. It's far more likely that you just need a new cordset but these often have molded strain reliefs that are specific to the product. The...
  20. KJ6EAD

    Solder Help!!!! PLEASE!!!

    It sounds like they drag soldered it without flux. Using a clean tip with lots of reservoir area, flux and reflow in a vertical drag technique to clear the bridges. If there's too much solder for this technique alone, use solder wick to remove the excess. The videos linked show some of the...
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