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  1. alfa88

    Dremel 395 VSC

    Mystery Part With nothing to lose I managed to pop the coating off the mystery part. It just looked like the resistive stuff that comprised the variable resistor and the 30k resistor hidden underneath the triac. It measured 5Megohms in both directions.
  2. alfa88

    Dremel 395 VSC

    Clarification Oops. Fixed the drawing. When I first took a look at the board (with an eye loupe) the trace appeared simply scorched. After examining the picture I noticed melted metal (blob). I then Ohmed out the trace and it was indeed open.
  3. alfa88

    Dremel 395 VSC

    Raw Pic I took another look at the pic and was a blob. It turns out that on porcelain looks can be deceiving. I ohmed it out and found the area to be open. A repair could be made but it would be temporary at best. At least I made a nice schematic.
  4. alfa88

    Dremel 395 VSC

    My Dremel finally went bad after a sputtering. I can find a replacement switch/control cheap enough but I wanted to make sure it wasn't something else 1st. so I did some research. Hopefully this will help others. Btw the easiest way I found to bypass the board is to pull the control board out...
  5. alfa88

    Braun Toothbrush Schematic

    Diode The diode will appear shorted if the motor is still attached. If, indeed, the diode is shorted just try squeezing in a 1n4xxx . we're only dealing with 3V and any 4xxx series diode should be able to handle the current. One Problem I came across was a poor connection to the motor's body.
  6. alfa88

    Tenma 72-6805

    Praise the Electron God I just knew I had the schematics stashed somewhere! On that note I'm letting you all know that in an act of great customer service Tenma gave me these. By the way there are no obvious signs of trauma on the board. At least I have a road map now:D
  7. alfa88

    Tenma 72-6805

    Helllp. I need a service manual or at least a schematic for my poor oscilloscope. My model comes with a built in sig gen. and that's the section that went haywire. The range and function selections are scrolling by themselves.:eek:
  8. alfa88

    Help on transistor design

    Transistor Theory Here is an alternate view of transistor theory: http://amasci.com/amateur/transis.html
  9. alfa88

    Edge Detector

    Integrator: Yes Thx. I came up with this circuit and it behaves exactly the same. I am assuming that the impedance of the capacitance affects the gain. I looked for practical applications but it left me scratching my head. Any thoughts?
  10. alfa88

    led problem

    Suggestion I have some of those too. The quick answer is no. Try running more than one in parallel (with resistors) to reduce the occurrence of off time.
  11. alfa88

    Edge Detector

    Edge Detector? I just came back from a job interview and they had me evaluate an op amp circuit. I'm pretty sure I got it right but what do you guys think? On the input was a 2 Vp-p square wave @ 1kHz, the output a triangle wave, 6Vp-p @ 1khz. The negative slope of the output coincided with the...
  12. alfa88

    Gateway Laptop Capacitor

    Just Sayin' I had a similar rebooting, shutdown, weird screen problem with a Dell and it turned out that the RAM was not fully engaged in the socket. The steamy hot CPU is a different matter. That's why I mention a default bios setting.
  13. alfa88

    Gateway Laptop Capacitor

    Try these 2 things Pull your ram out and clean the contacts. Make sure they are completely seated when you reinstall them. On the bios screen find and select the default settings.
  14. alfa88

    Complete Newbie - Please help with battery polarity & ribbon cable

    Advice Here's what I'd do to verify polarity. With no battery connected and the power switch off measure resistance from each of the connectors that go to the battery to the screw tops or the chassis. The one that has zero ohms is the negative terminal. This works in almost every case.
  15. alfa88

    Sailor needing advice

    I think what you're looking for is an audio distribution amp. Use Google and look at various products.
  16. alfa88

    Beginning Electronics Rtotal

    In Lieu of School In lieu of going to school get one of those 101 project things at Radio Shack or EBay. Go through the course. Build some kits and if you're lucky they wont work and. You can cut your teeth on troubleshooting them. There are plenty of people here to hold your hands. I used to...
  17. alfa88

    Return of the noisy neighbour punisher

    In the 'States As much as I admire noise making devices I'd hate to think that your situation escalate to the point of violence. In the 'States, after trying to personally resolve the matter fails, the next course of action would be to contact the local constabulary. Should that fail the next...
  18. alfa88

    In need of RF part ID part 2

    Spot on. Thanks.
  19. alfa88

    In need of RF part ID part 1

    Thanks I think you're right. I still can't find much info about it but I'll assume that the center freq. is 900mhz not only because it says .9 on it but it came out of a pager radio. In it goes to my bag of tricks.
  20. alfa88

    In need of RF part ID part 2

    I'm stumped on this part too. Same story except I searched for MCL. I'm guessing it's a crystal filter .
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