- Help identifying a blown IC and resistor - 3 Updates
- wireless client bridge signal strength measurement - 1 Update
| Jannie Brand <janniebrand@gmail.com>: Nov 10 06:15AM -0800 Hi Folks I have a COMMAX DRC-4L Video doorphone camera that isn't working anymore. This is part of a faulty Commax CDV-43k/DRC-4L (Stock Code: PI-1176) intercom that I basically got for free. I think something must have shorted or gone wrong as the power supply board of the main intercom unit (CDV-43k) itself (converting wall power of 220v to 15v) was blown. I've been able to replace the power supply board and had to replace some components (mainly a few ferrite beads and a resistor or 2, if I remember correctly) on the main PC board of the intercom unit itself as well. After that it seemed that the intercom was working and I connected the DRC-4L camera unit, which seemed to power on and the LEDs came on as well, but the camera feed didn't display on the intercom screen. After confirming that everything seems to be correct on the intercom unit, I suspected the camera itself to perhaps also have an issue or perhaps even some blow components. Long story short, once I remove the camera unit completely, I noticed 2 blown components on the back. An surface mount 6-pin IC (marked U8) and a SMD resistor (marked R23). Here is a link to some photos: https://imgur.com/a/8hWJyiy. From what I can make out from the remain bits of the code on the resistor, it seems like the code could be 75R0, which means it's a 75 ohm 0805 SMD resistor, right? Please let me know if I at least got that right. The IC however, I have no idea what it could be. I'm also not sure of the exact orientation of the chip, in other words where pin 1 is located, but I have indicated on the image which pin I suspect is pin 1. Based on my suspected pin 1, I can tell you that pin 2 is most likely the ground pin, as that is the only pin that has a direct connection (short) with ground. I was also able to detect 12V on pin 3 & 4 when the camera was powered on. Something else that I noticed was that there is a similar looking 6-pin IC, marked U9, towards the right-bottom corner of the board (as indicated on photo: https://imgur.com/a/8hWJyiy). The code on that IC is AJ6LE. I checked the same pins and it seems that pin 2 is also ground and I also detected 12V on pin 3 & 4. I am unable to find any information on the AJ6LE IC online, so I don't know if anyone here could maybe help to find out what exactly that IC is, so that we could hopefully determine if it is likely the same as the IC that has blown. Otherwise I have also tried searching online for information on the camera board itself, but couldn't find anything that gave me any indication of the specs of the IC or what IC to try and replace it with. I also tried to search for the schematic, but couldn't find anything. Also the leads coming into the camera board is: - Red is 12V+ - Blue is GND - Yellow is Video Here is a link with a few photos of a circuit board that isn't working anymore: https://imgur.com/a/8hWJyiy If anyone can perhaps help me identify the blown IC or perhaps point me in the right direction that would be greatly appreciated. Let me know if you require any other information from me. Regards, Jannie |
| "Peter W." <peterwieck33@gmail.com>: Nov 10 07:34AM -0800 That appears to be a current device - or at least it is available on the open market. Have you tried the "mother ship", being the manufacturer? Here, also, is a current source: https://www.megateh.eu/products/commax-intercom-outdoor-stations/commax-drc-4l-video-doorphone-camera Peter Wieck Melrose Park, PA |
| "ohg...@gmail.com" <ohger1s@gmail.com>: Nov 10 08:31AM -0800 On Wednesday, November 10, 2021 at 9:15:56 AM UTC-5, Jannie Brand wrote: > Let me know if you require any other information from me. > Regards, > Jannie Those six pin ICs are trouble. Some of them are only switches, and you can work around them assuming you know exactly what you're dealing with. Somewhere in a box I have a very expensive portable HDMI generator with that type of chip that failed and burned the numbers off it. I don't really need it anymore, but it would be nice to have anyway. |
| Dan Purgert <dan@djph.net>: Nov 10 12:39PM -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Jerry wrote: > Is there any way to easily measure signal strength of a wireless client > bridge? Yes, in your WiFi AP's (or router, if it's one of those combined gateway devices) UI, probably somewhere under "WiFi Clients" or similar. Well, assuming the AP makes it visible. If the AP doesn't, then no. > But how can I _measure_ (easily) the signal the other way around? According to Netgear's documentation, you can't. Or rather, the device doesn't display connected client strength. > [...] -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE3asj+xn6fYUcweBnbWVw5UznKGAFAmGLvX4ACgkQbWVw5Uzn KGBRoRAAia5qX0VkiFkmr1WzinRASEWLaeudb2+RTJ7gESftecrOQQiEfqqTArrL wm2GitmAXkrstTr/btuoWiD7cSpVN9zSFbcxGGWwJ/X0uSKIKi3HaDfSbcLQprEH QR/lzGSnscHLJhXs+MY0dViwVcy//xwIKJw9ABo4+iv+rEAitE7bELeD5dt6T0zC mYfMflpOOOq9UC7sM0jJIhUizRDpn4HmlwcWT6RtoTjNK4VyXCMHvShp/P467nVy AMyHUloVuIq/UpV8zxoZyFgOrHlN2JFF10M5UmS4HSE2vXQyooq3IYQ67Y1jTtm5 HROrcwuOj6xzTR3t0gLelrDlheavpIhpE6L5mUW/JDK2sRskvTRjhsXAsz/B29Pq 7cV0uevT/B3VTvwBvHxC6EepXBzol6q3Z9Mt7+Hc1kNZ+t9xnKvom/uNo8obb90R St8mKWwLrK84i6YNc3YqrY4K5C9xhqiK7GfyTomgJSD/8BeI8aL8vIyXuaEUMSed 2O7eoUvKR1sJ4CskKDubJZ9KsCMZwYKlEWex2ROq9g9xyrnnYjI2/RlwtzgNnxOV 7Es/CK42i1fUoUhD88N9Y/vl+5S7hBBcncBPuYe2Pn+pWoi8qxStAlcpMHupzuc3 OthvpMpS5fT2+ohWAPRnqYDrQo8e0AMUEwdVvet5+zZlmi3prew= =no8Q -----END PGP SIGNATURE----- -- |_|O|_| Github: https://github.com/dpurgert |_|_|O| PGP: DDAB 23FB 19FA 7D85 1CC1 E067 6D65 70E5 4CE7 2860 |O|O|O| Former PGP: 05CA 9A50 3F2E 1335 4DC5 4AEE 8E11 DDF3 1279 A281 |
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