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LC 475 chimes but no video output
- Thread starter bilbomacuser
- Start date
I do recommend at dip in a tub of isopropyl and light scrub all areas, sockets remove whats removable. Have saved myself tons of time and frustration just cleaning the board properly and let dry. Each to thier own on this though
OK, thanks - might try a proper clean. Have done that previously with other boards. My conclusions so far are that it boots promptly with the RAM SIMM slot empty, but not with either of the 4MB or the 32MB SIMM that worked last week. Cleaning the SIMM contacts and the socket with Servisol Super 10 hasn't made any difference.
Hello from southern Wiltshire!
The fact that pressing the red button makes it come back + the fact that the symptoms really line up with the lack of a battery makes me wonder. I'd be looking at that bit of the board personally. I'd check that the battery is making good contact with the holder (and is in the right way around! Not that I've done that. Multiple times). Then check that the battery voltage is making it onto the board and to the Egret chip.
The fact that pressing the red button makes it come back + the fact that the symptoms really line up with the lack of a battery makes me wonder. I'd be looking at that bit of the board personally. I'd check that the battery is making good contact with the holder (and is in the right way around! Not that I've done that. Multiple times). Then check that the battery voltage is making it onto the board and to the Egret chip.
Wow, another person from the UK - hi! Bathing the board in isopropyl alcohol appears to have done the trick. When I first booted it there was no image on the monitor - but then I heard a beep (a warning about energy saver or similar) - and then I realised I hadn't plugged in the monitor cable!
Working with the original 4MB RAM SIMM and original 2 x 256MB VRAM. Will try now with the other modules...
Working with the original 4MB RAM SIMM and original 2 x 256MB VRAM. Will try now with the other modules...
Could well just have been grot then.
Working with the 32MB SIMM and the 2 x 512MB VRAM too. Thanks for the help everyone! Maybe I'll start asking about a weird issue with an LCII that makes a high pitch whine - that varies in pitch over time!
Sounds like cap juice affecting something in the sound chip area. Is it coming from speaker or psu??
The sound is coming from the speaker on the LCII - sounds a bit like an old fashioned kettle with a whistle, though sometimes the pitch is steadily increasing like a kettle coming to the boil, sometimes it’s decreasing in pitch like a bomb falling!
By the way - the LC 475 had the no display/boot issue return today. It had been on for several hours, and nothing I tried got it working. Then I left it turned off for an hour or so, came back and it worked fine. Seems like related to being powered on for a while - so presuming heat causing expansion?
It's occurred to me that I've been running the LC 475 without the cover on. I remember that Mac's like the PowerMac G5 need the case to be closed for the cooling system to work effectively - does the same apply to the LC models? Perhaps I'm causing it to overheat?
No, it's not that. These run fine without the cover on (not advised for long periods but I've never had an issue doing it).
Do you have another power supply you can try with?
I’ve tried previously with the power supply from the LCII and it didn’t make a difference. Both have good voltages.
The lc ii most likey has cap juice under sound chip and other chips in the area. My lc ii made nasty noises until I cleaned all those up. Had to remove and clean pads, check traces etc. recapping only one part of the restoration..
OK, thanks. I thought that might be the case. I don't have a hot air gun, so will probably have to live with it for now until I feel brave enough to give that a try.
That's one special 475! 1 GB of VRAM!!! I bet it can do 4k, yes?
I know you meant kB, but I couldn't resist the opportunity to have some fun....
c
Actually, the LC 475 does provide video output even with the VRAM removed. Without the VRAM the screen resolution is just one pixel. If you make a screenshot in this state you get a file with a single black dot. As long as the video output is not necessary, the machine remains fully usable. That might come in handy if there is a shortage of VRAM modules and the computer is intended to be used headless, as a print server for example.
