IP3M-941B, IC U35 Shorted, help? Need part LD71C

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apschreiber
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Joined: Mon Sep 28, 2020 5:28 pm

IP3M-941B, IC U35 Shorted, help? Need part LD71C

Post by apschreiber »

Just bought a used IP3M-941B on eBay... non working. When I plugged it in, it draws over 2A and then the supply overloads and cycles. I found that U35 on the main board is shorted. It was easy to find as 2 amps generates a ton of heat. Anyway, the IC is a 5-pin DIP and the only markings are LD71C. There's a couple of them on the board.
A search of the innerwebs comes up with nothing related. Usually I have good luck finding discrete parts, but not here. So, I'm reaching out here for help.
If anyone has a similar cam not working for parts only, let me know. It looks like I need a donor cam!
Thanks in advance...
-Aaron
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Revo2Maxx
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Re: IP3M-941B, IC U35 Shorted, help? Need part LD71C

Post by Revo2Maxx »

Hello and Welcome to the Forum

Sadly that is an issue.. There will be no IC that you will find for a Direct Replacement that is because the CHIPS are made in China for China and they don't keep same numbers...

Then here is the Next Question do you have the Right hardware to be able to make such a SMALL SMD change? There are loads of Micro Resistors right around that package and the others as well these are not in most cases marked with what value they are and without the right Soldering Equipment it is going to be very easy to blow up the pads and traces...

I don't know that 941B but I can tell you that on others there are an Audio Power Supply chip of the same name.. To be honest I would remove that chip for Audio power and replace the main power AKA your U35 and make sure that it is even a Viable option.. Why because in a 841E I had to order the Main power Chip for my camera to wait for 6 weeks and install the chip to find out that the Camera it self is bad.. Ask myself later why I didn't do more testing before repair? How do I know that the Camera is bad? Well after spending all that time on my Camera Repair connecting everything back up and screwing the back on just to find out that the Camera would Pan and Tilt but give me no image I removed the setup and took a second 841E removed its board and had same results So I took the repaired MB and installed it in my second Camera housing and it works with that camera module..

So I know that sadly what ever caused my Main Chip to fry has to be related to the Camera module itself...

841 Cam1 Bad board (Fix board still didn't work)
841 Cam 2 Good working. (Took MB tested in Non working Camera module still not working.. Took fixed board tested in Cam2 camera module and Cam1 MB works with Cam2 Camera Module however don't work with Cam1 Camera Module)
Try to Avoid CCA Networking Cables They are JUNK PERIOD!
Where there is Life there is Hope
James
apschreiber
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Joined: Mon Sep 28, 2020 5:28 pm

Re: IP3M-941B, IC U35 Shorted, help? Need part LD71C

Post by apschreiber »

Revo2Maxx...
Good points. I did remove the problem IC to see if just removing that would allow the rest to power up. It didn't. My current is too low. Instead of robbing one of the other chips from the same board I'll wait on another parts unit or something. I can do limited work on this small stuff but it isn't easy or doesn't always turn out well. So the less I do the better my odds.
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Revo2Maxx
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Re: IP3M-941B, IC U35 Shorted, help? Need part LD71C

Post by Revo2Maxx »

Sadly the First Chip to go is the Main chip without it the rest won't power...

When I bought my Chips I bought extras to be safe and even with my 40 years of Soldering I ended up using 2 because the first one didn't like my Hakko Station so much lol...

For the biggest issue is if you look at data sheets for units inside USA for me anyway I couldn't find any that had good enough current or voltage ratings.. I have since found some from Newark, So I had to buy from Outside of USA and why it took so long to get them...

Anyway the Package so you can try and find them if you look around they are a SOT23-5 Package LDO Voltage Regulator.. Sadly the seller that I bought mine from is no longer listed.

I would look at Newark for your part, again itis called Sot23-5 or some might call it a SOT-23-5.. By the way don't put in a 100V one lol.. Might if you don't know what they are or how they work look over some Datasheets and get an idea of what your looking for..

However to be fair the cost of these cameras are so low that for the time and Effort it might be best to just invest in a new one..
Try to Avoid CCA Networking Cables They are JUNK PERIOD!
Where there is Life there is Hope
James
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