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  1. Externet

    Tektronix 2336 scope no horizontal trace

    From several dozens of oscilloscopes I have repaired successfully, that 2236 has been the champion of the nasty ones. Its power supply is so convoluted that I wanted to puke. Tektronix showed with that model family how crappy they can design one with the purpose of saving 5 cents. I wanted...
  2. Externet

    I would appreciate advice-need to add earphones jacket to a radio

    Well, you need to know the pins of the jack you obtain and wire it properly Tried to find a schematic and most of images show plugs instead of jacks...:( 2 and 4 should connect to internal audio amplifier outputs L, R. instead of to speakers 3 and 5 should connect to internal speakers , R+, L+...
  3. Externet

    Power line adapters

    .... And what are mb ? milibars? milibits ? Did you try an ethernet connection with no wifis ?
  4. Externet

    Far-field antenna polarization...

    Hi. Read somewhere that a television receiving antenna should be horizontal polarized. Also read that many miles away, it does not matter if the signal is received with a vertical polarized antenna, will perform the same :confused: Can anyone explain how it works ? What polarization are old...
  5. Externet

    Marine Beacon schematics for project

    If this is true, seems cheap ones exist ----> https://www.erfoxh.com/globalfix-pro-406-epirb-man-rel-with-gps But until you decide; a $10 green laser aiming up can be very helpful at night...
  6. Externet

    Chasing down excessive power consumption

    With the ownership of a house with 140 light bulbs I would had demanded and moved the hell until the seller/builder delivers ALL blueprints, electrical and not.
  7. Externet

    Chasing down excessive power consumption

    Wow ! Well, start working on it ! Shutting those breakers off will tell you soon what ceased working ! No, should not be that much. Perhaps some sweat drops ! Afraid of sweat ?
  8. Externet

    Pigeons electronic repeller

    Hi. Non-poison solutions take some effort depending on the place invaded by the pigeons. Impeding the birds from landing/nesting by placing needles/spikes/wires takes the strategy and danger of a ladder. Electrocution or shock treatment as with electric fencing for cattle is possible and seems...
  9. Externet

    Simrad VHF radiotelephone handset speaker - poor sound

    I would open the tinny distorted sounding handset and connect another similar speaker instead of the original to diagnose if the speaker is bad; then replace it with whatever performs in it. If the audio amplifier or path in it is producing the same problem with the replaced speaker, take some...
  10. Externet

    Can I mix 3 different brands of electrolytic capacitors?

    Using different brands of capacitors should not be detrimental. Try not to use the brands recognized as trouble-prone.
  11. Externet

    Simrad VHF radiotelephone handset speaker - poor sound

    Check if the handset/microphone connector in the VHF radio black box is similar to other transceivers and test/borrow another. You must isolate diagnosing to the main unit or the handset. There is nothing simpler than connecting a speaker and listening to its audio. Can you determine which pin...
  12. Externet

    Can't send gmail

    And such thing is not electronics.
  13. Externet

    Help with solar power system.

    Your solar panel may be capable of delivering 8.43 Amperes, IF the 30.2V batteries are discharged enough to accept them; and the 20 Amperes is the designed output capability of your charge controller.
  14. Externet

    How to find info on this peculiar transformer below?

    Hi. It is the same type of laminated toroidal we used at manufacturing audio equipment. Once I did find its website with data ; you will have to dig deeper in the era of switching supplies. (Billion electric) Similar available like at ----> https://www.ebay.com/c/25028815865
  15. Externet

    Where to find schematic of 315MHz receiver module ?

    If you are not aware of the currency...
  16. Externet

    Where to find schematic of 315MHz receiver module ?

    Superb response Edd. Thanks again. Edd, you NEVER short change me or anyone. -The 'India' is just as found that image on the web matching exactly my modules numbering-
  17. Externet

    Where to find schematic of 315MHz receiver module ?

    Hi. It is exactly like this one : ----> https://robu.in/product/rf-transmitter-receiver-module-315mhz-wireless-link-kit-for-arduino/ The 8 pin IC on it is LM358. Had no luck.:(
  18. Externet

    Any 433/315MHz receiver hacker around ?

    OK. Ordered Rx modules apparently with a similar to these schematics; as a guess of hack-friendly. Will scratch my head until arrive, and if you see something to suggest, welcome.
  19. Externet

    12v 0.5A auto trickle charger

    Good question. The internals should give a clue, make a schematic + pictures of what you see and bring it here. Many good modern chargers are discarded because as you say, need to detect the battery-to-be-charged is healthy, and refuse to work connected to a dead piece of junk residing years...
  20. Externet

    Any 433/315MHz receiver hacker around ?

    Hi. Exactly to substitute ~$200 VHF receivers with these $2 chinese toys when the performance needs are forgiving enough. That is why the data sheets of those types of Rx ICs (not the modules !) should help discern limitations.
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