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IIci PSU suppression caps replacement

max1zzz

Well-known member
Got my IIci yesterday, and as i suspected the suppression caps in the psu have failed

One of them i can find very easily (0.22uf 250VAC) but the two smaller ones are proving harder to find (4.7nf 250VAC) am i right in thinking it would be ok to use a slightly larger value of cap here? (e.g 10nf ones are easy to come by)

Apart from that the IIci looks really good ;) had a red maxell battery in it, but luckily that hadn't leaked, also has some form of radius graphics card in it

-max1zzz

 

genie_mac

Well-known member
Are you sure the smaller ones are faulty? Is it clear that they have failed? I had a similar problem in my IIcx psu with a visibly blown filter cap (the large one) and replaced that only. Works fine now.

Technically the psu should work without the filter caps so you could temporarily try running it without them to see if it works and then replace the caps.

Btw what Radius card do you have in there? The IIcx I got from the UK has a Radius GS/CM in there. Strange beast :)

 

max1zzz

Well-known member
yeah, they are both badly cracked, although they havent failed yet they need replaceing

i'll go grab the card in a bit and let you know

Edit: it is a Radius PrecisionColor Pro 24X

 

Ike

Well-known member
The IIcx I got from the UK has a Radius GS/CM in there. Strange beast :)
My IIci also came with one of those... never got any monitor to show any output using that card... It disables the built-in video port so it must recognize it somehow.

Thanks for the info about the PSU's btw... have two machines that use the same type.

 

max1zzz

Well-known member
Thanks for the link, seems the 10nf's should be ok

Orderd a couple, hopefully i should have them on saturday

 

trag

Well-known member
One of them i can find very easily (0.22uf 250VAC) but the two smaller ones are proving harder to find (4.7nf 250VAC) am i right in thinking it would be ok to use a slightly larger value of cap here? (e.g 10nf ones are easy to come by)

Put two 10 nF caps in series and you have a 5nF capacitor. The behaviour of capacitance is the opposite of the behaviour of resistors. For caps, in parallel adds capacitance. In series divides.

 

max1zzz

Well-known member
caps in series divide, i did not know that, thanks !

Although i'm not sure there is room to put 2 caps in, i'll definatley look at it (good that i brought more of the caps than i needed)

 

max1zzz

Well-known member
I have just replaced all 3 of the 4.7nf caps with 10nf ones and it is working just fine

The only odd thing is that the IIci won't stay powered down, it turns on as soon as power is connected and turns it's self back on if you hit shutdown, this happens even after i recapped the logicboard

 

Ike

Well-known member
ehm, do you, by any chance have the back power button turned horizontally in the server position? Or are you able to press it?

 

Ike

Well-known member
Ah, great!

Kind of like the idea of the twist-able plastic part. On later models, it became a software feature in the energy options I believe.

 
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