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  1. elebish

    HV diode

    Try this for parts. http://microwaveglasstrays.com/
  2. elebish

    Sansui SP-2500 Speaker Crossover Repair

    Replace the "NP" caps. The resistors should be fine.
  3. elebish

    Problems charging a garden tractor battery

    Sometimes a "dead" lead acid battery can be rejuvenated with a charger that has that feature, Typically a rejuvenator injects pulses in the battery to clean the plates that are restricting current flow.
  4. elebish

    Amplifier Repair - electrolytic capacitors expose metal top?

    Typically, radial lead caps have leads that are isolated from the can which is probably aluminum. In that case, a dc voltmeter with 10 meg ohm input could read some voltage from can to chassis or PS gound since 10 meg ohms offers no real load to the voltage. Axial lead caps usually have one lead...
  5. elebish

    Hello Everyone, Newbie here ! Need help repairing a amplifier.

    Some more questions! I have the PCB 14A board schematic and layout diagrams. It shows only one channel so I am assuming both channels are identical. This is good because you can 'bump' the readings of the good channel against the readings of the bad channel. All output transistors are NPN (Q13...
  6. elebish

    Hello Everyone, Newbie here ! Need help repairing a amplifier.

    Since you are referring to this problem as a "right" channel problem, you must have 2 pcb 14A boards. Am I right? If not. then you must be referring to one half of a single channel amp; one half being the positive fed side and the other being the negative fed side. Make sure you measure the dc...
  7. elebish

    Hello Everyone, Newbie here ! Need help repairing a amplifier.

    You must be more specific. Where is the 56 volts coming from? "Was" or "is" coming from? Give us a link to the schematic and point out where the 56 is coming from. Is the negative 56 vdc good? Is this a stereo amp? Is it bridgeable? Ed.
  8. elebish

    PSU Repair- Transformer outputting wrong voltage. Help much appreciated =)

    Judging the transformers as marked, do this: Before starting, ohm the 2 zero points. Should be open. Now ohm the two 18 volt points. They should also be open. If so, connect the 2 zeros together. Measure for ac from there to each 18 marked point. Should get a few volts above 18 volts ac at each...
  9. elebish

    CD Tray Won't Open

    Look for a small hole in the front of the disc case and use a paper clip wire to push one end into the hole to release the tray. If no hole, you will have to remove the case. Ed.
  10. elebish

    Multimeter

    Your voltmeter does not measure ac, it converts the ac to dc and measures it. So, look for a diode in the circuit and check it. It should measure .5 to .7 ohms with the negative lead connected to the banded (cathode) end. May have to disconnect one end of the diode first. If your measurement...
  11. elebish

    Fender stage 160 amp blowing fuses

    I assume your supply is 230 vac being in Canada. P8 connects to P11 and to one end of a .01 cap. P9 and P10 connect together and to the other end of that .01 cap. P7 connects to the 2.5 fuse and the other end of the fuse connects to an MOV. The other end of the MOV connects to P9 and P10. The...
  12. elebish

    Fender stage 160 amp blowing fuses

    All the wire colors look ok and the blue wires are ac so it does not matter in which order they are connected. Double check the big filter caps. They may open at the rated voltage. I don't suspect the bridge diodes since the caps would burn up and the fuse would blow if the diodes were shorted.
  13. elebish

    Fender stage 160 amp blowing fuses

    The red wires supply the 65 vac that develops the plus and minus 45vdc for the output transistors, the yellow wire being common to both. The blue wires supply the 17.8 vac that develops the plus and minus 15 vdv that powers the preamps. The brown wire being common to both. The red wires are P1...
  14. elebish

    TCXO or oven heated oscillator? Which one and why.

    I suspect the use of TCXO for bench and oven for portable when using an instrument out in the cold. Ed.
  15. elebish

    New guy just getting started need advice on tools

    Try ebay for an Iwatsu SS5711 or SS5710. I have the SS5711D. The D has the multimeter on top. I have had one for years and have used just about every scope made while working in the labs at Boeing for 38 years. You'll also need an isolation transformer to protect your equipment and items you...
  16. elebish

    Newbie question about 12Vdc fan

    If it has the same voltage and current ratings and moves air in the same direction as the old fan, it will probably work.
  17. elebish

    Fender stage 160 amp blowing fuses

    Keep the light bulb connected (100 watt), power up and check the temperature of the thermal run-away resistors of each output transistor with an 8 ohm load at the speaker outputs. They are the (less than 1 ohm 5 w) sand filled types. If one or more are getting a bit too hot too soon, there might...
  18. elebish

    Radio Receiver Circuit.

    AM means amplitude modulation. That is--the carrier changes amplitude at the rate of the modulation frequency and is detected with a diode in the receiver. That is--a dc is created which reflects the amplitude of the carrier at any given instant of time. That dc is the audio output and it is not...
  19. elebish

    Removing IC with rework station but when to grab tweezers?

    Generally, solder paste that melts at a low 419 degrees is used for populating an sm board so as to keep the heat as low as possible. There are 2 different types of machines that are used to mount sm devices. One is a vapor phase and the other is an ir wave. Typically, the board is preheated for...
  20. elebish

    Removing IC with rework station but when to grab tweezers?

    Flux the ic first and then heat. The solder will melt at approx. 419 degrees at which time the ic will "float" on the solder pads. Slightly bump the ic and it will move, ready to be lifted. Be careful not to heat too long or you may burn the board.
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