An interesting day.
I think we have finally found the cause of intermittent problems with the satellite TV boxes.
From beginning of production 0818 (18th week of 2008) they were fitted with Elna RE2J capacitors. 220uf 25v. Having tracked the ethernet issue to 2 of these putting ripple on the 1.2 and 2.6v rails, I pulled all 15 caps off a couple of boards to test them. ESR ranged from 1.1 - 13 ohms for the RE2J caps, 2 Nipon Chemicon KZE 470uf were .01 ohms, 2 Elna 470 uf RJB were .05 ohms.
Some time between 0918 and 0940 they started to use Nichicon VZ caps which measure between .23 and .4 ohms, the latter I think is a high ripple position on the 1.2v regulator cct.
The beginning of 2011 they fitted Nipon Chemicon KMG, I haven't checked these out yet, but they are not known to be a troublesome date.
That changed around 1140 when the fitted Elna RJ4's These tested from 1 ohm to over 100 ohms, or more than the meter can measure, 3 more of the 11 over 30 ohms. By 1218 they have moved to Taicon VT series which seem to be OK.
This is what I can find on the caps
Brand Series Ripple (ma) ESR
Nipon Chemicon KMG 230 0.16
Taicon VT 250 @120hz
Elna RJ4 247 1.21
Nichicon VZ 240
Elna RE2J
No Data on RE2j, Unlike most on Ebay (brown) These are blueish black. Brown made in Thailand, Black in Japan???
Wow the RJ4 has high ESR, is that the cause of the failure do you think, maybe it was the same for the RE2J?
I believe Elna has a good name so I suspect that they may have chosen the wrong caps.
I think we will have to change these 11 caps in a couple of hundred thousand boxes
on top of the power cable from PSU to main board, HDD Sata power cable, Tuner sockets.
The never ending train wreck these things have been.
The cap we are looking at using is the Nichicon PW series. Fairly cheap and better specs.
BTW, apart from seeing a couple of caps with the tops swelled over the last 5 years, but not really bulged like the KZG Chemicons on the tuner sometimes do. These caps that I have tested all look perfectly OK. These are being used in digital circuits, around ram and flash chips so may not be what they were meant for.
Any thoughts? Thanks
I think we have finally found the cause of intermittent problems with the satellite TV boxes.
From beginning of production 0818 (18th week of 2008) they were fitted with Elna RE2J capacitors. 220uf 25v. Having tracked the ethernet issue to 2 of these putting ripple on the 1.2 and 2.6v rails, I pulled all 15 caps off a couple of boards to test them. ESR ranged from 1.1 - 13 ohms for the RE2J caps, 2 Nipon Chemicon KZE 470uf were .01 ohms, 2 Elna 470 uf RJB were .05 ohms.
Some time between 0918 and 0940 they started to use Nichicon VZ caps which measure between .23 and .4 ohms, the latter I think is a high ripple position on the 1.2v regulator cct.
The beginning of 2011 they fitted Nipon Chemicon KMG, I haven't checked these out yet, but they are not known to be a troublesome date.
That changed around 1140 when the fitted Elna RJ4's These tested from 1 ohm to over 100 ohms, or more than the meter can measure, 3 more of the 11 over 30 ohms. By 1218 they have moved to Taicon VT series which seem to be OK.
This is what I can find on the caps
Brand Series Ripple (ma) ESR
Nipon Chemicon KMG 230 0.16
Taicon VT 250 @120hz
Elna RJ4 247 1.21
Nichicon VZ 240
Elna RE2J
No Data on RE2j, Unlike most on Ebay (brown) These are blueish black. Brown made in Thailand, Black in Japan???
Wow the RJ4 has high ESR, is that the cause of the failure do you think, maybe it was the same for the RE2J?
I believe Elna has a good name so I suspect that they may have chosen the wrong caps.
I think we will have to change these 11 caps in a couple of hundred thousand boxes
on top of the power cable from PSU to main board, HDD Sata power cable, Tuner sockets.
The never ending train wreck these things have been.
The cap we are looking at using is the Nichicon PW series. Fairly cheap and better specs.
BTW, apart from seeing a couple of caps with the tops swelled over the last 5 years, but not really bulged like the KZG Chemicons on the tuner sometimes do. These caps that I have tested all look perfectly OK. These are being used in digital circuits, around ram and flash chips so may not be what they were meant for.
Any thoughts? Thanks
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