I was given an Ace 1000 recently, and my first step when I received it was to crack open the power supply to check for any potential sources of noxious fumes waiting to be released.
Sure enough, it had two 0.1uf Rifa X capacitors. I have a bunch of modern X2 replacements on hand, so I replaced them. As I was about to put it back together though, I noticed a smaller but similar looking capacitor that says "MINIPRINT" on it, and is marked "0.1uf K" . The other side has a small Rifa logo!
Googling these things has come up with NOTHING except for places selling these capacitors.
I just tried powering the PSU on without it being connected to the motherboard, and it does turn on (with the two Rifa X caps replaced), but I get a pretty pronounced repetitive ticking sound. It's very distinct... sounds like a wind-up clock ticking steadily. It's hard to tell which component it's coming from... but it isn't that Rifa Miniprint cap, so I don't think that's related. Seems to be coming from one of the components near the heatsinks, but I can't quite pinpoint it.
I tried checking the voltages on the power supply pins and I get around 5.15v from the orange pin and -11.7 from the brown pin. The rest just make my DMM's flash back and forth between zero and nothing, as if it's fluctuating a lot (I'm not that experienced with this stuff, but it's a decent old Fluke 75). I don't have an analog meter to see what that says.
Is there any chance the ticking and voltage measurement issues may be related to the PSU not being connected to the board? I know on some much later power supplies they don't test properly unless under some kind of load... but this is my first Apple clone (or Apple compatible of any type) so I'm in new territory here.
I just don't want to plug it in and fry something on the board if I have a chance to fix it first.
Any help is much appreciated.
EDIT: This isn't my picture but it seems identical to mine before I replaced the two caps. You can see the Miniprint K cap in the lower left corner. The ticking sound seems to be coming from the area around the heatsinks and the four tall caps in a row.
https://i.imgur.com/NVVOkkm.jpeg
EDIT2: Found a thread here about a ticking sound in a similar Apple:
http://www.vcfed.org/forum/showthread.php?51808-Apple-IIe-Power-Supply-Failure
Sounds like it's the power supply overvoltage protection, since it doesn't have the load from the motherboard. Heh, oopsie... at least I've learned something without making anything explode. :D
Anyway, tomorrow I'll test out the power supply in the computer. I'll post back here with my findings.
Sure enough, it had two 0.1uf Rifa X capacitors. I have a bunch of modern X2 replacements on hand, so I replaced them. As I was about to put it back together though, I noticed a smaller but similar looking capacitor that says "MINIPRINT" on it, and is marked "0.1uf K" . The other side has a small Rifa logo!
Googling these things has come up with NOTHING except for places selling these capacitors.
I just tried powering the PSU on without it being connected to the motherboard, and it does turn on (with the two Rifa X caps replaced), but I get a pretty pronounced repetitive ticking sound. It's very distinct... sounds like a wind-up clock ticking steadily. It's hard to tell which component it's coming from... but it isn't that Rifa Miniprint cap, so I don't think that's related. Seems to be coming from one of the components near the heatsinks, but I can't quite pinpoint it.
I tried checking the voltages on the power supply pins and I get around 5.15v from the orange pin and -11.7 from the brown pin. The rest just make my DMM's flash back and forth between zero and nothing, as if it's fluctuating a lot (I'm not that experienced with this stuff, but it's a decent old Fluke 75). I don't have an analog meter to see what that says.
Is there any chance the ticking and voltage measurement issues may be related to the PSU not being connected to the board? I know on some much later power supplies they don't test properly unless under some kind of load... but this is my first Apple clone (or Apple compatible of any type) so I'm in new territory here.
I just don't want to plug it in and fry something on the board if I have a chance to fix it first.
Any help is much appreciated.
EDIT: This isn't my picture but it seems identical to mine before I replaced the two caps. You can see the Miniprint K cap in the lower left corner. The ticking sound seems to be coming from the area around the heatsinks and the four tall caps in a row.
https://i.imgur.com/NVVOkkm.jpeg
EDIT2: Found a thread here about a ticking sound in a similar Apple:
http://www.vcfed.org/forum/showthread.php?51808-Apple-IIe-Power-Supply-Failure
Sounds like it's the power supply overvoltage protection, since it doesn't have the load from the motherboard. Heh, oopsie... at least I've learned something without making anything explode. :D
Anyway, tomorrow I'll test out the power supply in the computer. I'll post back here with my findings.
Last edited: