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My tube light choke was not working, I tested its circuit using multi-meter and found that a capacitor (labeled 622JA on first line and GD 1000 on second line) was short-circuited so I pulled it out and tested, same result.

There is no documentation or information available online for that part number. Is there a replacement for that part or where do I find it on existing circuits that I have?

Update Image and Dimensions:

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Update - Solved I replaced it with 1600v 7.32nf capacitor (a red giant one), it is working fine.

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  • \$\begingroup\$ If you ohm it out with the resistance measurement, what do you get? What is the designator on the PCB for this part? \$\endgroup\$
    – Voltage Spike ♦
    Commented Sep 23, 2019 at 16:51
  • \$\begingroup\$ 0.7ohm and it was connected parallel to 2 center points (total 4) which connect to light rod, on output (fixed error in the post it wasn't connected to ac) \$\endgroup\$
    – asim
    Commented Sep 23, 2019 at 16:58
  • \$\begingroup\$ GD is a chinese company, can't find their website \$\endgroup\$
    – Voltage Spike ♦
    Commented Sep 23, 2019 at 17:23
  • \$\begingroup\$ Any idea for a replacement capacitor? \$\endgroup\$
    – asim
    Commented Sep 23, 2019 at 17:25
  • \$\begingroup\$ Need to find a datasheet first, its unlear what the markings mean \$\endgroup\$
    – Voltage Spike ♦
    Commented Sep 23, 2019 at 17:33

2 Answers 2

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It appears to be a 6.2nF, 5% tolerance ceramic capacitor rated for 1000V.

The Wikipedia page for capacitors includes a section on markings.

The first two digits are the value. The third is the multiplier.

For 622j it looks like this:

62pF * 10^2= 6200pF= 6.2nF.

The tolerance code "j" stands for 5%.

The voltage rating is the other number on the capacitor.

That 1000 means "1000 volts."

Here's what you need to look for in your relacement part: 6.2nF, 5% tolerance, 1000V.

I am surprised that it has gone bad. You can usually recognize a bad ceramic capacitor because they crumble or crack.

If you are using an ohmmeter to test it, that probably won't tell you much.

You need to use a capacitance meter to test it.

If you don't have one, but you do have a small AC transformer and an AC voltmeter then you could try this:

  1. Depending on the AC powerline frequency, get a resistor of either 510k (for 50Hz) or 430k (for 60Hz.) Those are the approximate impedances for a 6.2nF capacitor at the given frequency.

  2. Solder the resistor in series with the capacitor, and connect to the low voltage side of the transformer to the ends of the capacitor/resistor.

  3. Measure the AC voltage across the capacitor.

  4. Measure the AC voltage across the resistor.

  5. Both voltages should be approximately equal.

If your capacitor is shorted (as you think) then you will measure zero volts across the capacitor and the full voltage from the transformer across the resistor.

I think you will find that your capacitor is OK.

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  • \$\begingroup\$ I understand the rest but AC transformer part seems dangerous to me as i am a software dev with some knowledge of electronics, i have a dozen faulty smartphone/other appliances chargers and a microwave transformer (not touching that) \$\endgroup\$
    – asim
    Commented Sep 24, 2019 at 19:57
  • \$\begingroup\$ On the low voltage side it is safe. But, not everyone has an AC output wallwart handy. \$\endgroup\$
    – JRE
    Commented Sep 24, 2019 at 20:30
  • \$\begingroup\$ See update on my question, many thanks @JRE \$\endgroup\$
    – asim
    Commented Sep 25, 2019 at 17:45
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This is poly capacitor of 6.2nF with 5% tolerance 1000V

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