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  1. S

    HP 8903A Audio Analyzer schematic

    Repairing old Hewlett Packard 8903A, unfortunately, the only manual I have is for prefix serial numbers 1942A through 2016A, and the instrument I'm repairing is S/N prefix 2433A. My problem is A2 Input Amp Board (HP #08903-60114). With no access to a schematic for THIS board, I can't ID the...
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    Repairing Keithley 480 picoammeter motherboard

    Did you try Keithly? www.Keithly.com
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    Unknown Diodes

    Anybody recognize any of these diode markings? I suppose the numbers might be a date code, but I would like to know if anyone recognizes this marking system. (What company, or any information) SCU844 SCU808 SCGI819U SCGI829U Thanks
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    Motor or solenoid

    Don't know your application or metering of the dosing. If dosing needs to be precise, consider using a peristalic (metering) pump, if the dosing is also a fluid. There are other methods if you're introducing a powder to the fluid flow. What kind of additional information can you provide on...
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    Panasonic 5 disk changer helpp!

    Like LTX71CM said, that black box below the power supply cord in your picture, sure looks like a relay to me, that might be the clicking you hear. I also notice the black component 45 degree angle up from the cord, looks like a heavy- duty transient voltage suppressor of some type. If it's...
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    Magnifying glass & third hard

    Depends what you want to do, and how much you'll pay. I tried a couple of the small all-in-one jobs. They're small, the base is small, and tip-over. But if you're doing small work, it might work. I work so many different jobs, years ago I invested in a Panavise. Their suction cup base is...
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    service menu codes

    I guess next time, I'd look for a TV with support. Any possibility of emailing the actual manufacturer? If you can get ahold of them, the might help (even if it's out of warranty).
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    service menu codes

    One other idea, would be to look for the model number of your REMOTE, and google that.
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    service menu codes

    Probably like you, I couldn't find anything on the internet about it. If I was stuck like you, I'd start accessing the menu drop downs (LOOK, you might have multiple menu push-buttons to check), and start looking for your setup menus). Hopefully somebody else on this site will come-up with...
  10. S

    Batteries in the fridge

    I know in the wintertime, if I leave my flashlight in the car, the alkaline batteries are dead in less than a month. Cold may not be a good idea for these new battery types.
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    High-Voltage capacitor charge indicator.

    Yep, *steve*'s right. You're going to zap just about anything else you use, besides a neon bulb. (If you don't zap yourself first) Get your car out of the way in your garage, before you fire that thing.
  12. S

    Help ?

    The ones I've seen seem pretty specialized to certain areas. When googling, try to narrow your search to your hobby area more specifically.
  13. S

    Different types of 555 timer

    LM555 is another common name for this timer. Make sure you get a DIP (dual in line) package, if you're wanting this for breadboarding. Since you're planning to order some, check some of the circuits you want to build, and make sure you've got the resistors and capacitors you'll need too.
  14. S

    building a strong solenoid

    Laplace is probably right. Solenoids have very small distance-travel actuators, and you want to open a drawer, so you'd have to have a lever to transfer the small actuator stroke, into a long-length distance for the drawer. The other thing to consider, is the drag of I assume, wood drawer on...
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    Batteries in the fridge

    I remember having to do that with spare batteries for the old flash-camera attachment. Sorry, I don't know about the new alkalines, and even then, the actual chemical composition might vary between manufacturers. Maybe somebody else on this site will have a better answer. If I was you...
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    Marantz 4300

    The problem would be if the speakers are very low power, and even the low volume setting on your Marantz is a fair amount of wattage. Just something to think about, next time you repair that circuit, and consider outputting the power to the speakers. Good luck with it. I was just thinking your...
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    Will fuse blow....with repetitive overcurrent pulses?

    I'm with *steve*. Like Barathbushan said, your fuse it better than a fast acting one, but we don't know your circuit. You sound like you EXPECT repetitive pulses, and your circuit may cause the fuse to heat. If this is going to be a continuous thing, you're just asking for the one time when the...
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    Keep relay actuated longer

    I don't know if this is a school project, and you're stuck with existing components or not. A cheap solution would be at add an LM555 timer. Check a data sheet or the internet for some good circuits. National Semiconductor data sheets usually give you several good simple application...
  19. S

    Internal fuse blowing, CD650, help understanding circuit

    Watch out for your large electrolytic capacitors near that bridge too. I don't know how old the unit is, or where you stored it, but the electrolytics seem to go more often than anything else in power circuits (causing damage to other components like the bridge rectifier).
  20. S

    Marantz 4300

    Was just wondering if maybe you bought it from some foreign seller. You need to watch out for those speakers you're using. If you're overdriving the 'dinky' 8-Ohm speakers you're using, THAT WILL blow your output transistors.
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