find faulty capacitor in circuit if there are many
- Thread starter Kardo22
- Start date
- Joined
- Nov 17, 2011
- Messages
- 14,270
The strategy is "divide and conquer":
Split the line in half (meaning with respect to the number of capacitors half of them on each side of the split. Check each half for the fault.
Split the faulty half line again in half (so you have 2*1/4 of the original line). Check again for the fault.
Continue until the fault is located.
For n capacitors, you will need max. lb(n) splits instead of checking n capacitors (lb = binary logarithm, base 2).
Split the line in half (meaning with respect to the number of capacitors half of them on each side of the split. Check each half for the fault.
Split the faulty half line again in half (so you have 2*1/4 of the original line). Check again for the fault.
Continue until the fault is located.
For n capacitors, you will need max. lb(n) splits instead of checking n capacitors (lb = binary logarithm, base 2).
- Joined
- Nov 28, 2011
- Messages
- 8,393
That won't work - they're all in parallel! They will all measure short.
There are ways to do this by passing a current into the short and tracing the voltage drop across the copper traces or the current flow in them, but you need a current tracer or a sensitive voltmeter, and you need to trace the positive and negative tracks. Do some Googling.
Well, it kinda will.
If you can measure down to milliohms you can measure the resistance of the track or wires. If you can do that, you can search for the point with the minimum resistance and that will be close to your short.
Specialist tools (like a leakseeker, or toneohm, or any of these) are also available as Kris suggests.
Colin Mitchell
- Aug 31, 2014
- 1,416
- Joined
- Aug 31, 2014
- Messages
- 1,416
The first things to suspect are transistors, then IC's. I have repaired 45,000 products. Maybe one or two shorted tantalum capacitors in Blaupunkt TV's - but they are the last thing to suspect.
