converting a pcb to schematic.

[roy]

I have 2 small pcbs about 3inches by 2 inches. One had 3 op amps and the
other has 3 ic, and several transistors along with various resistors,
diodes and capacitors. I need to obtain the circuit from the board
inorder to troubleshoot it . It is used in a governor control.
Is there any software or are there people who will convert it to schematic
for a price ??? If there is software that can convert it at least (very
basic conversion) to a schematic, it would really help. Its very difficult
doing it physically as the printed circuit is double sided though not very
complex. I have clear photographs of both sides of the boards.

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[ian field]

I have 2 small pcbs about 3inches by 2 inches. One had 3 op amps and the
other has 3 ic, and several transistors along with various resistors,
diodes and capacitors. I need to obtain the circuit from the board
inorder to troubleshoot it . It is used in a governor control.
Is there any software or are there people who will convert it to schematic
for a price ??? If there is software that can convert it at least (very
basic conversion) to a schematic, it would really help. Its very difficult
doing it physically as the printed circuit is double sided though not very
complex. I have clear photographs of both sides of the boards.

First of all sketch the component side and itemise all the components and
their values.

I find it helps to scribe the component symbols on the solder side with a
sharp pointed knife (scalpel).

You will reach a point where the evolving schematic is beginning to make
sense but the finer details of the tracks are getting harder to follow.

Now is the time to start carefully removing components so you can trace
point to point with a DMM on low Ohms range.

As long as you document each stage you shouldn't have any problem putting it
back together.

 

[Robert Lacoste]

First of all sketch the component side and itemise all the components and
their values.

I find it helps to scribe the component symbols on the solder side with a
sharp pointed knife (scalpel).

You will reach a point where the evolving schematic is beginning to make
sense but the finer details of the tracks are getting harder to follow.

Now is the time to start carefully removing components so you can trace
point to point with a DMM on low Ohms range.

As long as you document each stage you shouldn't have any problem putting
it back together.

A good alternative to removing components to follow the tracks behind them
on a double ou multilayer board is simply... to Xray the populated PCB ;+).
Just ask it as a favor to your best doctor friend...
Yours,
Robert

 

[Eeyore]

I have 2 small pcbs about 3inches by 2 inches. One had 3 op amps and the
other has 3 ic, and several transistors along with various resistors,
diodes and capacitors. I need to obtain the circuit from the board
inorder to troubleshoot it . It is used in a governor control.
Is there any software or are there people who will convert it to schematic
for a price ??? If there is software that can convert it at least (very
basic conversion) to a schematic, it would really help.

Might be simpler to write software to convert Klingon to English !

Its very difficult
doing it physically as the printed circuit is double sided though not very
complex. I have clear photographs of both sides of the boards.

You'll have to do it 'by hand'.

Suggest you start by identifying circuit 'nodes' and then placing the
components as connected to them.

Graham

 

[GregS]

Might be simpler to write software to convert Klingon to English !


You'll have to do it 'by hand'.

Suggest you start by identifying circuit 'nodes' and then placing the
components as connected to them.

Do a reverse image of one of the images, then overlay the two.
You could use clear mylar. Laser machine does it well.

I just usually do it the hard way, and also make use of a bright
light on reverse side.

greg

 

[Ross Herbert]

Not a possibility. You will need to do it "by hand".

I have a similar problem in front of me right now only it is quite a bit more
complex than your board sounds. Mine is a double layer board and many of the
components cover tracks so you can't tell where they go visually. I either buzz
them out or in some cases I revert to completely removing the component from the
board in order to trace the tracks.

You will also need to identify all of the components (IC's and other semis) and
download their datasheets so that you can determine schematic connections and
pin numbering. Your first efforts at drawing a schematic will be rather crude
and you will need to check and double check the connections before arriving at a
correct result. After sevewral iterations your schematic will eventually look
like the original would have but it can take a day or 2 to get that far.


:
:I have 2 small pcbs about 3inches by 2 inches. One had 3 op amps and the
ther has 3 ic, and several transistors along with various resistors,
:diodes and capacitors. I need to obtain the circuit from the board
:inorder to troubleshoot it . It is used in a governor control.
:Is there any software or are there people who will convert it to schematic
:for a price ??? If there is software that can convert it at least (very
:basic conversion) to a schematic, it would really help. Its very difficult
:doing it physically as the printed circuit is double sided though not very
:complex. I have clear photographs of both sides of the boards.
:
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:
:
:
:
:
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elivered via http://www.electrondepot.com/
:Electronics Enthusiasts' Community of the Net
:Web and RSS access to your favorite newsgroup -
:sci.electronics.components - 22985 messages and counting!
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