Advice on discontinued capacitors (Full specs included)

[myristate]

Basically got a Dell motherboard with bad caps. One is circled in yellow in the first pic. It is a Rubycon and the only one on the whole motherboard of that type. There is also a set of 4 caps circled in blue and red they are Nippon caps and the same. The ones in blue seem fine but the ones in red have the smallest of pinpricks of what appears to be a black spec dead centre. I would like to be cautious and replace all the caps. However, After finding their datasheets and looking them up I cant find any suppliers that sell them as they appear to be all out of production. From what I have read in the forums ultra low ESR caps have been replaced by polys (Not entirely sure what that means). I should mention that while I am an electrician and do use a soldering iron from time to time; electronics is not something I know too much about. I wouldnt know what I could replace them with that would be sufficient and what values I could accept at a higher/lower value. Below are the datasheet specs for both typoes of caps. Hoping someone could poihnt me to a range or type that would fit the bill.

Rubycon (Only 1 on the board)
Capacitance: 1800μF
Model/Range: MCZ
Voltage: 6.3V
Diameter: 8mm
Length: 20mm
Temp: -40 to 105 °C
Tolerance: ±20% (20°C,120Hz)
ESR(ΩMAX/20°C, 100kHz) : 0.012
Rated Ripple Current (mA r.m.s./105°C, 100kHz): 2350

Additional markings on Capacitor:
T0646
PET


Nippon Chemi-Con (4 in group, 2 look suspicious)
Capacitance: 2200μF
Model/Range: KZJ
Voltage: 6.3V
Diameter: 10mm
Length: 20mm
Temp: -40 to 105 °C
ESR(ΩMAX/20°C, 100kHz) : 0.011
Rated Ripple Current (mA r.m.s./105°C, 100kHz): 2920

Additional markings on Capacitor:
6(7)
0b

[stj]

Re: Advice on discontinued capacitors (Full specs included)

poly's = solid polymer electrolytics.
they have lower esr and higher current than the best liquid electrolytics.

and they are really your best and only option here, because as you said - all the really low esr caps (MBZ, MCZ, FL etc) are discontinued.

[myristate]

Re: Advice on discontinued capacitors (Full specs included)

Well if picking out these new poly capcitors do I just need to match the voltages and capacitance values? Im just not sure what diffrent values of ESR or ripple current will do? Ive read that these are important in certain types of circuits

[stj]

Re: Advice on discontinued capacitors (Full specs included)

diameter must match,
voltage should match if you dont know the actual voltage of the circuit,
capacitance should be kept close, but 1500 for the 1800 or 2000 for the 2200 should be fine.

[stj]

Re: Advice on discontinued capacitors (Full specs included)

this will do the KZJ's nicely.
free delivery too
http://uk.rs-online.com/web/p/alumin...itors/8392133/

[myristate]

Re: Advice on discontinued capacitors (Full specs included)

Excellent thank you!