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190cs: fuse location??
Posted by: desertrout on 2021-08-23 15:31:09 I'm troubleshooting some power / display issues on a 190cs, and the tech reference refers to a fuse on the logic board to test... but for the life of me I can't locate it. I'm going cross-eyed and beginning to think it doesn't exist. Does anyone happen know if there is a fuse, and where it is?? Here are some reference photos (not mine, but the board is the same): https://oldcraporg.files.wordpress.com/2020/11/dsc_0001-1.jpeg https://oldcraporg.files.wordpress.com/2020/11/dsc_0003-1.jpeg
Posted by: desertrout on 2021-08-24 07:19:02 So, here's what I'm trying to troubleshoot: the machine boots immediately after plugging in the PSU but with no video. The machine apparently continues to boot to desktop, but there is nothing on the screen. I can adjust the backlight, adjusting contrast makes no apparent difference. I've performed the typical PRAM / power manager reset, but no change. Battery is dead (of course), but symptoms are the same whether it's in or out. Symptoms are also the same whether the RAM card or floppy drive or hard drive are installed or not. I've seen this same behaviour in a 1xx series PB when the fuse was blown, so that's where my attention is focused. The repair manual for the 190/5300 series suggests checking the fuse on the logic board, but I can't find it and I kinda don't think there is one... but this is the 'newest' logic board I've ever worked on, so could just be ot recognizing it. Recapping both the logic board and display boards is on my TODO list, but this machine was reputedly working before it was shipped to me, so I'm scratching my head.
Posted by: desertrout on 2021-08-25 19:48:34 Alright, made a new PRAM battery and that has cleared up the auto-start issue and other power management quirks. Seems to be behaving normally on that front. Still no video though, despite many (many, many) minute-long power manager resets and PRAM zaps (I heard sometimes it take a crazy number of tries)..... video cable seems ok (not verified), but if a recap doesn't make a difference then toning it out will be my next step.
Posted by: desertrout on 2021-08-31 19:56:14 Closure - it was the flex cable, in a couple places. Naturally. 🙄
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