Author Topic: PCB to scheme.  (Read 1650 times)

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Offline deandadnaedTopic starter

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PCB to scheme.
« on: April 06, 2019, 09:55:05 pm »
Hi!

I’m trying to understand and simulate a Power Supply. Wiring is very clear for me. But the PCB’s aren’t.

Is there a way to reverse engineer a PCB and obtain its diagram/scheme?

The first piece I want to describe is this:




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Offline viperidae

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Re: PCB to scheme.
« Reply #1 on: April 06, 2019, 10:07:11 pm »
Take a picture of the track side, print it out then draw the components on it.

From there it's much easier to start drawing out the schematic
 

Offline deandadnaedTopic starter

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Re: PCB to scheme.
« Reply #2 on: April 06, 2019, 10:30:19 pm »
Take a picture of the track side, print it out then draw the components on it.

From there it's much easier to start drawing out the schematic
Thank you very much!


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Offline alex.martinez

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Re: PCB to scheme.
« Reply #3 on: April 06, 2019, 11:50:21 pm »
Hi!

I’m trying to understand and simulate a Power Supply. Wiring is very clear for me. But the PCB’s aren’t.

Is there a way to reverse engineer a PCB and obtain its diagram/scheme?

The first piece I want to describe is this:

Enviado desde mi iPhone utilizando Tapatalk

At least it is a one-sided board. The problem with power supplies and several-model electronics is that they make a master PCB with all the features, then fabricate that one, and for lower-tier models they remove some of the sub-systems.

The advice above is pretty solid, but take into account not all component hoels are populated... and probably there is a good portion of traces shorted to ground. I would start from there, use te continuity meter and start checking which ones are shorted, where do the "0 ohm" go and so on.
« Last Edit: April 07, 2019, 12:36:56 am by alex.martinez »
 

Offline jerryk

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Re: PCB to scheme.
« Reply #4 on: April 07, 2019, 12:34:29 am »
Here are some different views of your board that might be helpful.

Jerry
 

Offline soldar

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Re: PCB to scheme.
« Reply #5 on: April 07, 2019, 09:09:36 am »
Here is a composite view of a power supply I had to repair. This is a reduced size, the original is larger. It allowed me to reverse engineer the schematic and then repair it.

I flipped over the photo of the traces and superimposed a transparency of the components and annotated by hand in two different colors for traces and for components.

A good way to kill some time and forget your troubles. Very therapeutic. Especially recommended after an argument with the wife. (Or, better still, before even thinking of arguing.)
« Last Edit: April 07, 2019, 09:18:57 am by soldar »
All my posts are made with 100% recycled electrons and bare traces of grey matter.
 

Offline soldar

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Re: PCB to scheme.
« Reply #6 on: April 07, 2019, 09:15:57 am »
A SMPS with a double sided PCB.

Correction: After looking at it again I think it is single sided but I colored the GND green and the rest blue. They do not cross so it looks like single side. There are wire bridges in red.
« Last Edit: April 07, 2019, 04:51:06 pm by soldar »
All my posts are made with 100% recycled electrons and bare traces of grey matter.
 


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