PCB Repair

[MaineEvent]

I see alot of Ebay auctions for PCBs that are tested and not working....
Is it crazy hard to diagnose and repair PCBs? What kinds of tools do you need?
I'd appreciate any incite, thanks!
 



Maybe NOT this one

[M.Lanza]

It depends on your skill level with electronics.

Do you know what each component on the pcb does,
or how an individual component may affect the operation
of other components on the pcb?

Can you narrow down a non-specific, general error,
to a failure in one or more components using specialized
electronic diagnostic equipment that takes special training
to use properly?

What would you do if you narrow down a failure to a very rare,
specialized chip that hasn't been produced in at least 20 years
and is not cross-compatible with any other chip currently available?

[WhereEaglesDare]

I  soldering iron with an assortment of tips
helping hands
flux and a good soldering iron cleaner
a solder sucker and wicking braid (for desoldering)
an excellent ability to read schematics
You need to know how power protection circuits work, how to desolder without burning traces or overheating semiconductors
you need an isolation transformer (depending on the type of repairs you want to do)
you need a Model 73 or better Fluke Multimeter
and you will need a working oscilloscope.  the OScope is really important especially on monitor repairs.
you will also need all the manuals, books, electronics dictionaries, etc that you can get your hands on.

If you are truly interested let me know I may able to help you out some.  Ive been doing board repair off and on for 8 years.

[MaineEvent]

Wow thanks for the quick responses!
Yuck...
 I definitely don't know what each component on any given PCB does...
Sifting for rare old chips does not sound like fun either
So in relation to doing a cap-kit this sounds like a horrible pain in the ass that I should just pay the extra few bucks for, rather than try and repair a board!

Right now I have a Shinobi that is giving me crazy lines

[WhereEaglesDare]

Yea you would definitely need a OScope to fix that.  You from Maine?  Im flying up there this weekend I can bring some schematics and stuff

[MaineEvent]

Not anymore... Im in Vancouver now
But thanks for the offer!
 

Going hunting?

[WhereEaglesDare]

Nope, gotta go for work, I love it up there though, I was up there for two months last year

[CheffoJeffo]

While I have always wanted an oscilloscope, I've never heard of one described as required, particularly with respect to monitor repairs.

As for finding old chips, there are a number of vendors who specialize, including at least one BYOACer, but WED has a point -- it can be hit and miss.

Randy Fromm's podcasts are available on his site and do provide a shortcut or two that have worked for me with PCB repair in the past.

[WhereEaglesDare]

While I have always wanted an oscilloscope, I've never heard of one described as required, particularly with respect to monitor repairs.

As for finding old chips, there are a number of vendors who specialize, including at least one BYOACer, but WED has a point -- it can be hit and miss.

Randy Fromm's podcasts are available on his site and do provide a shortcut or two that have worked for me with PCB repair in the past.

How can you trouble shoot a sync signal, y signal, etc without a oscope?

[CheffoJeffo]

It has been my experience that, the majority of the time and particularly with monitor repairs, there are easier ways to find the fault. For monitor repairs, you will get FAR more mileage out of Randy's flowcharts than you will with a scope.

Having said that, I have a TMNT board with an audio problem that I can't for the life of me figure out (and it has been years!), so what do I know ?

[WhereEaglesDare]

It has been my experience that, the majority of the time and particularly with monitor repairs, there are easier ways to find the fault. For monitor repairs, you will get FAR more mileage out of Randy's flowcharts than you will with a scope.

Having said that, I have a TMNT board with an audio problem that I can't for the life of me figure out (and it has been years!), so what do I know ?

Youre probably right, I havnt seen any flow charts for monitors, my experience is working on TVs and depending on the model you cant find schematics and have to do it the hard way with a scope, thats why I say its so important.  Where are the charts?

[BobA]

I have a couple of scopes and do not use them that much for regular digital logic repair.   I find that a logic probe is faster and can help trouble shoot a problem very quickly.  TV repair as any analog circuits definitely benefits from a scope but old arcade PCBs do not usually need them.

http://en.wikipedia.org/wiki/Logic_probe

[MaineEvent]

Great information guys, I will definitely check out Randy Fromm's stuff...and also look more into the logic probe.
I would love to be able to fix PCB's and save them from the landfill or being parted out. Plus it will keep me away from turning to the dark side (MAME)
Thanks again!