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  1. elebish

    Testing capacitors in amp circuit

    There should be a small non polarized (NP) electrolytic capacitor in the crossover network that blocks the low frequency from getting into the tweeter. I would just replace it since that would be simple and inexpensive. The 22ufd may be the culprit!
  2. elebish

    Help selecting the correct Diode

    I would use the schottky diode instead of the regular silicon but both will work fine. No rocket science here!
  3. elebish

    Technics SA-5760

    You will probably have to troubleshoot the power supply as this is the most common problem that will affect both channels with the same noises. Clean the volume control if you have a dusty environment. Next, the main filter electrolytic capacitors should be disconnected and temporarily...
  4. elebish

    Need help with pendulum clock

    Those transistors may be FETS? Not sure.
  5. elebish

    Can't identify if transistor is PNP or NPN?

    Very true but my method is much simpler, inexpensive and better for a novice. I have one and love it. I use it instead of my curve tracer unless I want to match one device to another.
  6. elebish

    Amplifier blows power fuse

    I can only tell you what I would do to test all those high powered output devices since it would take a lot of time to check all of them since the same dc power source is feeding them all. I would use a 61/2 digit lab grade ohm meter to check between VCC and -VCC of each device. The one showing...
  7. elebish

    Scope calibration

    Most late model scopes use a crystal controlled time base oscillator. From that is derived all the sweep frequencies needed for the bandwidth of the scope. Check the freq of the oscillator and insure it is on freq. Generally the frequency used is 10 Mhz and there should be a small variable...
  8. elebish

    Technics SA-5760

    Check the line voltage for overvoltage and noise. May need a scope to do that and will really know how to use it for proper triggering and source.
  9. elebish

    Can't identify if transistor is PNP or NPN?

    Purchase a "PEAK" atlas DCA55 semiconductor tester from MCM Electronics. Inexpensive and will tell you everything you will need to know about transistors including lead ID and specs and whether the transistor is bad or not.
  10. elebish

    Someone please help clicking relay

    One end of the diode must be removed to check the forward voltage drop across the diode. The purpose of that diode is to block the reverse magnetic field from briefly re-energizing the coil. You'll need an ohmmeter with a diode check mode to check the diode. Typically, you'll read about .6 volts...
  11. elebish

    Smoked capacitor

    Do NOT use a screwdriver to discharge caps, Use a 5 watt 1k resistor. If a cap is blown there is the possibility that a diode in the PS is shorted.
  12. elebish

    FG106 Function Generator

    Pulling out at the hubs of the handle should allow enough room to remove the cabinet.
  13. elebish

    Pioneer VSX-827 -k

    After checking the power supply rails for proper dc voltages, the next logical point would be the pre-amps. It is highly possible that an LSI is used (large scale Integration). A commonly used type would be an STK350-430. Trouble shooting a malfunction like yours is not easy due to the small...
  14. elebish

    HV diode

    Try this site. I seem to think you have a bad magnetron which you can purchase on this same site: http://microwaveglasstrays.com/shop/-c-23.html
  15. elebish

    Power supply noisy inductor

    Check C28
  16. elebish

    I want to replace a noisy capacitor in a TV

    Make sure that the resistor is soldered properly to the board and not a cold solder joint that could lead to arcing. If the relay has a diode across the coil, replace the diode. Diodes are used to eliminate back EMF from the coil that can cause chattering of the relay.
  17. elebish

    HV diode

    If the diode is ok and arcing is occurring, the magnetron is putting out, however there should be no arcing in the oven unless the magnetron is improperly mounted. There should be no arcing inside the magnetron unless it is defective. Make sure the oven chamber is clean and void of food...
  18. elebish

    Akai S1100 sampler ...bad capacitors?

    Those 'bulging' caps probably have small inductor coils internally and are classified as filters accordingly. If they read shorted, that would be due to the coil.
  19. elebish

    Amplifier blows power fuse

    Check the black round component (MOV) between the transformer and white connector with red leads. If shorted, that could be your problem. If not, isolate the dc output from the power supply and clamp (substitute) the voltages to the output transistors with a current regulated supply. Another...
  20. elebish

    DIY Resistance Box

    If you are not using it for frequencies above 30 KHz, a box will be better. A pot is usually a half watt which is not very high and there will also be insertion loss containing capacitance and inductive reactance affecting your circuit depending on frequency. A wirewound pot would be the worst...
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