| General > General Technical Chat |
| Bought some old speakers from ebay - here's what I found inside |
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| MrMobodies:
--- Quote from: DrG on May 16, 2021, 09:51:45 pm ---You could make a schematic :) --- End quote --- I remembered when I believed I use to recognize actors from pictures many years ago doing things like exploring abandoned buildings but no name apart from the teams who were regular in their exploration so I used this tool a number of times to see if their face match from their official photographs. Peekthrough https://www.lukepaynesoftware.com/projects/peek-through/ Hope the attached images helps (with different transparency levels) for someone who wants to do a schematic and would be interesting to draw it on Falstad. |
| themadhippy:
--- Quote ---I was curious as to what that was and found it in a 1978 Fairchild catalogue. --- End quote --- no need to go back to 1978,its still widely available today. |
| MrMobodies:
OOps I got a bit confused, "F 4013BPC" I believed I might have also made a mistake at some point which is why not much came up and looking at my history the "f" got lost somewhere leading me to that 1978 magazine. So I got the wrong part number so sorry about that. Will amend my post. I notice some with a space inbetween the F. F 4013BPC https://www.ebay.com/itm/F4013BPC-IC-DIP-4-PIECES-qzty-/282952293885 F4013BPC https://www.ebay.es/itm/303146097929 I see that putting it in exactly brings up a lot of results from foreign websites. https://www.google.com/search?q="F+4013BPC" |
| james_s:
--- Quote from: Benta on May 17, 2021, 09:15:00 pm ---Anti-theft device. the coils and the two caps are resonant circuits for the theft detector at the doors. The IC and resistors are pure camouflage (very usual back then). --- End quote --- Camouflage for what? The device is concealed inside the speaker, what would be the point of adding gratuitous components? |
| Cyberdragon:
--- Quote from: james_s on May 18, 2021, 03:01:43 am --- --- Quote from: Benta on May 17, 2021, 09:15:00 pm ---Anti-theft device. the coils and the two caps are resonant circuits for the theft detector at the doors. The IC and resistors are pure camouflage (very usual back then). --- End quote --- Camouflage for what? The device is concealed inside the speaker, what would be the point of adding gratuitous components? --- End quote --- They are all connected properly as the OP said. It is a frequency divider using a flip-flop. The resistors are probably for bias or something. What's odd is there does not seem to be a way to disable the device externally if it is a theft alarm trigger. |
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