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  1. 73's de Edd

    VHS Problems

    Come back with its model number and then test to see if it will load and unload a tape, since you already have its innards exposed. Then see if it can fully fast forward a tape to its end and fast rewind a tape to its beginning . . . . with you never hitting play mode, in which it apparerntly...
  2. 73's de Edd

    Help with LED backlight from TV

    Sir saberwolf617 . . . . . Is it still possible to connect the LED strips to the old tv to get it to light them up, to then be able to take voltage and current measurements in order to determine their NORMAL operating parameters ? DON'T want to overtax them in the eventual circuitry used /...
  3. 73's de Edd

    Help! Repairing water damaged PCB from Massage chair.

    Sir Club 200 . . . . . Do any of these "Taiwan" origin of units seem akin to your unit or being a clone ? https://www.alibaba.com/trade/search?fsb=y&IndexArea=product_en&SearchText=Taiwan+made+%22+Masse+%22+brand+of+massage+chair&isGalleryList=G Circuitry trace down might involve clear...
  4. 73's de Edd

    Trying to go from 12v ac to 12v dc

    The least invasive basic test / evaluation, would involve unsoldering just one of the YELLOW wires from the PCB and set it aside. Then run 12VDC battery power to the RED and BLACK wires at the BLUE filter capacitor to then be able to evaluate the unit, to see if BATTERY power will still...
  5. 73's de Edd

    fried board Identification

    Also hard to make out anything, but the primary part I see missing . . . . probably just cannibalized . . . is its main raw DC storage electrolytic . . .axial leaded . . . vertically . . .at the top left 1/4 corner area of the board. Most of those switchers already ARE being 95 thru 220V AC...
  6. 73's de Edd

    Geiger pulse detection circuit

    Sir sebswed . . . . . Assuming that you are properly getting the 400 VDC Geiger supply voltage by your circuitry and that it only requires a mere 1.6 VDC of power supply. The first error noted is the use of PNP transistors in the amp circuit . . .if you have the companion family brothers to...
  7. 73's de Edd

    2.4V Ni-Cd Charger

    Sir abuhafss . . . . . Hey that’s SOMEWHAT more than that prior paltry 4 ma isn’t it? So your charge circuit does seem to have some merit. I don’t know if the battery pack is pulled from the unit, but next do this. You need to still have the pack disconnected from anything, or just carry the...
  8. 73's de Edd

    2.4V Ni-Cd Charger

    Sir abuhafss . . . . . Are you presently using an adjustable power supply to get the initial 3.5 VDC input voltage being shown ? If I were using a wall wart to get that voltage, I would want about a minimum 5 VDC or so to get some minimal voltage headroom. That is . . . . considering the unit...
  9. 73's de Edd

    Monitor Won't Power On - LG Flatron L1751S-BN

    Sir hotmaildotcom1 CON-GRAN-U-LATIONS ! Small black one: 0.47 microFarads and 50V 105F Larger Green one: 33 microFarads and 50V 105F I am in total agreement on the PRINCIPAL 33 mike unit which you confirmed as being your units MAIN problem child. But, can you confirm the decimal...
  10. 73's de Edd

    Controller board fails to stay switched on

    Sir onlyme2 . . . . . Can we get a bit more info on the mark ups and some answers? I’m initially suspecting on setting battery problems, if being contained within that black “HOT BOX” case and getting on in multi years of use or even more. I’m wanting to think that the 4 YELLOW DOT...
  11. 73's de Edd

    Replace Relay with TRIAC?

    Sir CMA . . . . . Considering the infrequent switching needs . . . . ON when the car is running and OFF when the car is not being used. Along with: The milliohms of contact resistance of a mechanical relays contacts. Not having to worry about the “ trash “ being fed into the gate of a TRIAC...
  12. 73's de Edd

    Charging batteries in boombox while using it

    Sir megajonern . . . . . Considering past amps of that rating, is hard to perceive of that unit with its Lilliputian sized digital to analog filtering networks, of mini inductors and mini canned electrolytics components shown, getting those specs, even in a comical “Music Powered Ratings” at...
  13. 73's de Edd

    What way around are these voltage regulators?

    I just knew that on the side of the board shown, that I could see, I saw no transformer to get the required initial peak of 1000V upwards, to initially get a tube into striking and flashover and then a decline down to ~ 300-400 VAC for actual running.
  14. 73's de Edd

    What way around are these voltage regulators?

    Yep, shore did . . . . . . . YOU . . . . and heavy on the YOU, are more apt to encounter a BC 846-A on YOUR manufacturing side side of the big waters. While I, me,we,us and Mr 'tater man . . . . are more likely to encounter a MMBT3904 being on OUR boards. Didn't happen to see the "Code Book "...
  15. 73's de Edd

    What way around are these voltage regulators?

    Mister 'tater Man . . . . . . . With that low of a numerical coding assignment, I would suspect them being common transistors, likely a MMBT3904L in this case. Initially use the lowest OHMs function to confirm that what seem to be direct up and down foil connections between the two units...
  16. 73's de Edd

    Identify a varistor

    Sir adrien62400 . . . . . “Reading” off the parts stamped on info: Initially there is the Matsushita family of products logo Then the 7 relates to the ~ 7mm “slug” size of the active metal oxide element, which directly relates to its instant power handling capacity. Finally the 221...
  17. 73's de Edd

    Schottky Diode Case Connection - Why?

    Sometimes they also offer the device as a "R" version, in which case the diode polarity would be reversed. It was very common on stud mounted diode cases.
  18. 73's de Edd

    Unidentified Circuit

    Sir Nobby999 . . . . Considering that units thin PCB tops and bottoms and the construction manner, along with the encapsulating medium. It resembles an ULTRA high reliability (from a mechanical shock and environmental aspects ) ”cord wood “ module of aerospace and military electronics of the...
  19. 73's de Edd

    What component is this?

    Sir Viktor . . . .frum Sveden . . . I had already pulled and prepped my inserts prior to your data sheet posting but am going to include them also. I was also going to ask you to put a strong rare earth magnet against the unit to confirm the ferrite presence. Pulling a unit and measuring...
  20. 73's de Edd

    Monitor Won't Power On - LG Flatron L1751S-BN

    Sir hotmaildotcom1 . . . . . Here is a basic run thru of this units concept of operation: AC power enters [1] and passes thru an intact fuse [2] and into NTC Thermistor which cushions initial plug in power surge. Var001 clips any incoming short duration voltage spikes coming in from the...
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