One last try.
Measurements out of circuit:
The good way:
-Take a LCR meter that gives you D (=tan d).
- Look up the datasheet
- lookup D (=tan d = DF = 1/Q = related to loss angle)
- and the frequency they measured that, often 100 or 120 Hz (it was 1 kHz for a long time)
- lookup the max value of D, most times 200%
- Take a real LCR meter, set it at the stated frequency
- Measure C, is it within specs ? often +/- 20% when they are new, how low the circuit tolerates is an other question.
- A real LCR meter or bridge will give you D
- If both are within specs the cap is good. (if you want to go all the way you can measure leakage. (often stated for 2 or 3 minutes, this is not the working voltage leaking test, that is a test you do for safety.)
The easy way, but not always a good way
- replace the caps by the same brand an type new ones (nothing wrong with this)
- or with a suitable replacement with the same specs
- do not kill the pcb by using crappy desolder tools
- this did not help ? Do some real trouble shooting with things like a scope and multimeter.
I only repaired 3 TV's and non of them had dead electrolytics. (a shorted 1 nF 1kV cap, a dead 4 MHz Xtal and a shorted mosfet) but my satellite receiver needed over 40 new caps.)
The hard way:
- fire up your ESR indicator
- measure the cap in circuit
- spend an afternoon looking for tabels that gives the ESR for 2 uF and works for your indicator (so a Z or an ESR table)
- Then decide witch table could be the correct one.
- You do not know so start a bunch of new topics to get the same answer in all of them...or roll a dice
- before going mental you just replace the cap to be sure
3rd way:
- Fire up your impedance meter (a sweeping one or a simple DIY self ESR meter that does not measure ESR but Z, how convenient
![Wink ;)](https://www.eevblog.com/forum/Smileys/default/wink.gif)
)
- look up datasheet, note impedance Z at 100 kHz.
- is measured Z is withing the stated specs, the cap is good.
4th way, involves some math:
- fire up your real ESR meter
- measure the ESR at 100 kHz
- look up the datasheet and note the impedance at 100 kHz
- calculate the reactance of the cap (based on C measured at 100 kHz ) 1/(2pifC) for 2,06 uF = 0.773 ohm
- calculate Z ; in your case based on 1,2 ohm and 0.773 ohm makes: 1.427 ohm
- if Z is within the stated specs from the manufacturers datasheet the cap is good.
5th way,
- take a scope
- probe the power rails
- if there is to much ripple, replace the cap.
- how high the ripple is allowed to be is stated in the service manual of the thing you repair.
- if it is not stated you must estimate that. Not to hard, measure on the Vcc pins of some components.
You need electronic knowledge for that but you need that for repair anyhow (only swapping maybe-dead caps and random components is not really repair)
The very bad way:
- every way that measures component in circuit
![Evil >:D](https://www.eevblog.com/forum/Smileys/default/evil.gif)
You can do that if you want to quickly find the real dead caps in something that is so dead you can not start it. Then remove and measure them using one of the ways above. Then start the normal trouble shooting.