I have twin S1846 boards that won't any longer POST, and Slot1 Coppermine 700MHz and Katmai 600MHz to fit them. A slocket with 933 Coppermine won't POST either, No beeps. The graphics card does put a cursor on the display on power-up. Mixing the parts up doesn't change anything. Three different PSUs, and other RAM sticks don't help either. If there's anything on the web about S1846s routinely dying of old age, I've yet to find it.
These have 5 UCC LXF 1000uF 10V 10x20mm (codes 8(2) &4H), 4 Sanyo CG 1000uF 6.3V 8x11.5mm, 1 Gemcon seriesless 330uF 16V. All are near CPU slot. All tested OK with my ESR60 meter on removal from one of the two boards. It also has about 18 4x7mm I haven't given more than a peek at. Although tested OK, I've already replaced the Gemcon with a Nichicon PS and the Sanyos with Nichicon HM.
What to do about the UCCs is the immediate question. I read here that through most of the 1990s the LXFs were iffy, which is why I decided to try replacement. I could find no specs for LXF, only this page specifying UCC series suitable for replacing. The LXY 1000uF 10V 10x20 is in stock at Digi-Key at a pricey for their size $0.69USD each or $4.88USD for 10. Since I can't find a spec for LXF, I don't know what ripple is needed, while because of UCC's replacement table I should expect the 1.04A @ 100kHz of the LXY would be at least adequate. I'm baffled how same can sizes at same other specs can so often have a double or more ripple rating than other quality series.
I have several possibilities for 1000uF 10V replacements in stock:
Should I put the LXFs back? Should I spring for 10 (or more) LXYs? Which if any of my inventory should be suitable, given all seem to provide double the modest estimated ~1000 ripple required and be low impedance, same as the LXY. Should I expect nothing to help? What else on a motherboard would die of old age, the tiny electrolytics?
These have 5 UCC LXF 1000uF 10V 10x20mm (codes 8(2) &4H), 4 Sanyo CG 1000uF 6.3V 8x11.5mm, 1 Gemcon seriesless 330uF 16V. All are near CPU slot. All tested OK with my ESR60 meter on removal from one of the two boards. It also has about 18 4x7mm I haven't given more than a peek at. Although tested OK, I've already replaced the Gemcon with a Nichicon PS and the Sanyos with Nichicon HM.
What to do about the UCCs is the immediate question. I read here that through most of the 1990s the LXFs were iffy, which is why I decided to try replacement. I could find no specs for LXF, only this page specifying UCC series suitable for replacing. The LXY 1000uF 10V 10x20 is in stock at Digi-Key at a pricey for their size $0.69USD each or $4.88USD for 10. Since I can't find a spec for LXF, I don't know what ripple is needed, while because of UCC's replacement table I should expect the 1.04A @ 100kHz of the LXY would be at least adequate. I'm baffled how same can sizes at same other specs can so often have a double or more ripple rating than other quality series.
I have several possibilities for 1000uF 10V replacements in stock:
- Nichicon HM 10x16mm, 2000 ripple, 10V
- Nichicon HM 10x16mm, 2000 ripple, 16V
- UCC KZN 10x16mm, 2000 ripple, 16V
- Panasonic FM 10x20mm, 2180 ripple
Should I put the LXFs back? Should I spring for 10 (or more) LXYs? Which if any of my inventory should be suitable, given all seem to provide double the modest estimated ~1000 ripple required and be low impedance, same as the LXY. Should I expect nothing to help? What else on a motherboard would die of old age, the tiny electrolytics?
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