Electronics > Repair

Abandoned as an idea for a sticky - too hard basket.

(1/2) > >>

What_NZ:
Introduction: A suggestion for a sticky.
This is not intended to teach or tell experienced Technicians how to repair units. Instead it is aimed at the home hobbyist. Basically what to look for and importantly keeping them as safe as possible. I usually trained technicians and apprentices so it's a little different for me so any help would be appreciated. Also my technical writing skills have suffered since I retired.

These are the next 2 (suggested) Steps:
----------------------------------------------------------------------------------------------------------------------------------------------------------------

Basic Principles of Fault Finding / Fault Diagnosis or if you like, Repairing Stuff -

Observation > Confirmation >  Disassembly > Re-confirmation > Observation > Resources > Measurement > Repair > Testing > Assembly > Testing
Already covered: First Steps: Observation > Confirmation >  Disassembly > Re-confirmation

Second Steps: Observation > Resources

Observation:

- With the unit open and the fault re-confirmed we should now have a look at the general condition inside the unit.
Remove the Power cord and/or Batteries. If the unit contains high voltages it may pay to wait 5 to 30 minutes for the voltages to drop down to a safe level. While looking inside the unit try and avoid moving cables, we just want to look rather than remove or move anything. Start a complete visual inspection looking for anything unusual like, charring, arcing, leaking, deformed or overheating of components or the PCB(s) itself, damaged components, corrosion, cracks in the PCB, obvious dry joints especially on heavy components like heatsinks, relays, transformers, large capacitors, front panel switches. Keep in the back of your mind the fault you observed and maybe where inside the unit that fault may be.

Resources:

- Now could be a good time to gather extra resources you may find helpful and could save a lot of time.
The Internet is a wealth of information, Operating/User/Instruction Manuals, Service Manuals, Repair Tips, Electronics Forums and of course the EEVBLOG forums and educational Videos. When Googling for Manuals use the Model Number from the unit, try the Google Image search it may be quicker. Avoid paying for Manuals, most enthusiasts will provide them free. Remember Service Manuals are Copyrighted and sometimes distribution is restricted. Asking the Company who manufactured the product for one, will most likely result in a big fat NO and then advise you to take it to an Authorised Service Centre for repair.
When you ask for help on the Forums try to supply as much information as possible, like - the model number, a link to the Manuals, a clear description of the fault, what you have checked/confirmed/done so far and don't be surprised if they ask for clarification, photographs or something else. They are not trying to be difficult, they want to help. Overall be patient, helping to repair something they don't have in front of them is not easy. You may also be in a different part of the world (time zone) than they are.

Bored@Work:
So now that you have your "own" board you want to dictate the rules and continue to post your made-up "rules"?

Well, thanks for https://www.eevblog.com/forum/profile/?area=ignoreboards

What_NZ:

--- Quote from: Bored@Work on June 30, 2014, 04:59:41 am ---So now that you have your "own" board you want to dictate the rules and continue to post your made-up "rules"?

Well, thanks for https://www.eevblog.com/forum/profile/?area=ignoreboards

--- End quote ---

You won't be missed and why not add me to your ignore list too.

Kjelt:

--- Quote from: What_NZ on June 30, 2014, 12:48:17 am ---If the unit contains high voltages it may pay to wait 5 to 30 minutes for the voltages to drop down to a safe level.
--- End quote ---
A bit too vague to my likings, perhaps a suggestion to create a list of products that have this issues and where explicitly to look for and measure the voltages and how to discharge them before going further with the repair.

Perhaps even some safety shortcuts, I once saw a tech use a large (1000V insulated) screwdriver shorting all the big caps ("just to be sure") not the nicest way but quick and better safe then sorry.

What_NZ:
Yes it was a bit sloppy. How about this instead -

If the unit is powered from the AC mains, has a CRT type display or by function uses a high voltage then there is likely to be high voltages inside. You should either safely discharge the voltage or wait 5 to 30 minutes for it to drop down to a safe level.

Any further suggestions are welcome.

Navigation

[0] Message Index

[#] Next page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod