schematic from PCB

Thread Starter

SomLima

Joined Oct 14, 2022
5
Hi

I have a pcb board which is covered in mud and rust.
I believe this could be a reason it is malfunctioning.
The pcb board mostly controls a servo motor.
The pcb board a QR scan code.


Is it possible , once I clean it up from photos of the pcb , make a schematic so I can get a copy made from one of these Internet pcb board companies .

Regards

Som
 

Papabravo

Joined Feb 24, 2006
22,082
Hi

I have a pcb board which is covered in mud and rust.
I believe this could be a reason it is malfunction.
The pcb board mostly controls servo motors.

Is it possible , once I clean it up from photos of the pcb , make a schematic so I can get a copy made from one of these Internet pcb board companies .

Regards

Som
Yes, but it is tedious and exacting work. In addition, you need to have a basic understanding of the circuit and the components used in order to have a reasonable chance of success. You should at least be willing to throw the first one away because you will end up doing that in most cases. If there is a microprocessor involved and you are unable to dump the contents of program memory, then your chances are certainly reduced to a very low order of probability.
 

MrChips

Joined Oct 2, 2009
34,807
Welcome to AAC!

The only method I am aware of is to sit down and manually reverse engineer the board.

For repair, I would suggest you wash the board thoroughly with mild soapy water then rinse it with isopropyl alcohol.
Allow it to dry for a day or leave it in a desiccator. Putting it with uncooked rice in a seal plastic sandwich bag for a few days also works.
 

dl324

Joined Mar 30, 2015
18,326
Welcome to AAC!
Is it possible , once I clean it up from photos of the pcb , make a schematic so I can get a copy made from one of these Internet pcb board companies .
It can be done. It's easier, and less tedious, on single- and double-sided boards. When you get to 4 layers, or more, with buried vias, it can be extremely tedious.
 
I have a pcb board which is covered in mud and rust.
I believe this could be a reason it is malfunctioning.
The pcb board mostly controls a servo motor.
Well the PCB looks like it is dounble sided with most of the components being surface mount, all capacitors or resistors except for U1 which looks like it's through hole. No visible components on the other side. The 2 x 2 pins sticking through on either side of the motor shaft seem to go directly to the motor - presumably supply lines. All the cabling is on the left side of the PCB as we look at it, no connector, just soldered in. So the only mystery component is U1 - no idea what that is! If the black ring near it on the motor shaft is magnetic, maybe U1 is a hall sensor. But if you can take out the circlip on the motor shaft and extract and clean the board as previously suggested it may still be functional and U1 may have some marking on it to identify it. In fact, even if components on the PCB have failed, the chances are the bare PCB will stilI be serviceable. I would try to unravel and sketch the complete schematic, including everything the cable loom goes to. My suspicion for failure is more towards that rusty motor behind the PCB - or is it even a motor? Do you know what kind of "motor" that is and maybe there is a part number on it? And what is the piece of equipment we are looking at? We may learn more from knowing that.
 

Thread Starter

SomLima

Joined Oct 14, 2022
5
Well the PCB looks like it is dounble sided with most of the components being surface mount, all capacitors or resistors except for U1 which looks like it's through hole. No visible components on the other side. The 2 x 2 pins sticking through on either side of the motor shaft seem to go directly to the motor - presumably supply lines. All the cabling is on the left side of the PCB as we look at it, no connector, just soldered in. So the only mystery component is U1 - no idea what that is! If the black ring near it on the motor shaft is magnetic, maybe U1 is a hall sensor. But if you can take out the circlip on the motor shaft and extract and clean the board as previously suggested it may still be functional and U1 may have some marking on it to identify it. In fact, even if components on the PCB have failed, the chances are the bare PCB will stilI be serviceable. I would try to unravel and sketch the complete schematic, including everything the cable loom goes to. My suspicion for failure is more towards that rusty motor behind the PCB - or is it even a motor? Do you know what kind of "motor" that is and maybe there is a part number on it? And what is the piece of equipment we are looking at? We may learn more from knowing that.
This the rear axle steering axle from Mercedes Vito Taxi. It has a tendency to get clocked up then short circuit or just msy be the motor. The cost of new is price of car.
I am using WD 40 rust and contact cleaner to clean it up.

The numbers on the motor are still not yet readable .

I have attached more pictures
 

Attachments

panic mode

Joined Oct 10, 2011
4,975
i would consider getting the new unit, that one is corroded terribly. btw. the PCB appear to be the healthiest part in it...

also this does not have the Mercedes markings on it. it may be something used for small volume or aftermarket modification. and since the part number and contact info are clearly shown, did you try contacting manufacturer? this seem to be the common linear actuator. price for those is usually some $100, not the price of a car... but then... the Electro Pro is a discontinued product version. so i would decode part number and look for a substitute from same manufacturer if possible. based on data this is motor+encoder version, 12VDC, 12.5cm stroke (4.9inch), 500lbf. the PCB is the encoder. the difficult part is the custom stroke. standard products have stroke in increments of 2" (2,4,6,8...) but this is a 4.9" version. what exactly is this used for on that vehicle? if different stroke cannot be used maybe rebuild the dead unit with parts from a new one (keep the ballscrew... replace motor and encoder)

1665782995499.png
 
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Thread Starter

SomLima

Joined Oct 14, 2022
5
Thanks I am using the extremely information provided by you all.

This piece of equipment is used in rear wheel steering in Mercedes Vito Van when used as a London Taxi.
 
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