This is a question about substituting one capacitor for another. When you have a bad cap but you don't have exactly the same rating cap as the bad one to replace it with. How far can you deviate from the original spec?
Voltage is ok. You can go from 25V to 35V, for example, because if you only have a 25V feed that's the maximum voltage the cap is going to accrue. So the rule would be greater than is ok but not less than unless you are certain what the supply voltage is. Size is a consideration
as well because size tends to be bigger the higher the voltage.
Temperature and ESR also have to be considered too. The main question is about the capacitance rating. That's the grey area for me.
Are there any rules?
Recently brought a dead Toshiba TV back to life. There was a repair kit for the power board on eBay that consisted of 7 caps. Came with a list of locations. Very convenient because there were 16 caps on the board and they all looked fine.
But I noticed that one of the locations on the board had a 2700uF 16v cap that wasn't original. It's replacement in the kit was 3300 uF 16v. But on the wiring diagram that I found the spec was 4700 uF 6v. I queried this with the kit vendor and they said they were aware of this difference but had difficulty getting the 4700 uF 6v caps so went with the 3300 uF 16v rather than the 2700 uF 16v that "some people use". I found a 4700 uF 6v cap on eBay and used that. But the difference between the 2700 uF cap on the board and the 4700 uF on the wiring diagram seems pretty broad. I should point out that the 2700 uF 16v cap appeared to be fine when I removed it and tested it. Although all of the other caps looked fine 4 of them were well out of range. The TV works fine now.
So I was wondering is there any guidance or best practice as far as capacitance is concerned?
Thanks.
Voltage is ok. You can go from 25V to 35V, for example, because if you only have a 25V feed that's the maximum voltage the cap is going to accrue. So the rule would be greater than is ok but not less than unless you are certain what the supply voltage is. Size is a consideration
as well because size tends to be bigger the higher the voltage.
Temperature and ESR also have to be considered too. The main question is about the capacitance rating. That's the grey area for me.
Are there any rules?
Recently brought a dead Toshiba TV back to life. There was a repair kit for the power board on eBay that consisted of 7 caps. Came with a list of locations. Very convenient because there were 16 caps on the board and they all looked fine.
But I noticed that one of the locations on the board had a 2700uF 16v cap that wasn't original. It's replacement in the kit was 3300 uF 16v. But on the wiring diagram that I found the spec was 4700 uF 6v. I queried this with the kit vendor and they said they were aware of this difference but had difficulty getting the 4700 uF 6v caps so went with the 3300 uF 16v rather than the 2700 uF 16v that "some people use". I found a 4700 uF 6v cap on eBay and used that. But the difference between the 2700 uF cap on the board and the 4700 uF on the wiring diagram seems pretty broad. I should point out that the 2700 uF 16v cap appeared to be fine when I removed it and tested it. Although all of the other caps looked fine 4 of them were well out of range. The TV works fine now.
So I was wondering is there any guidance or best practice as far as capacitance is concerned?
Thanks.