I would totally buy it from you! I have another display but no cable. :O Please DM/PM me any details you need.
Macintosh Portrait Display Repair - Smearing/Pulsing Image on Screen
- Thread starter warmech
- Start date
Great fix. I came here because I was looking for a caps list. I may have a different revision, not sure. I will be opening it up and if I have a different revision I will identify it and list the caps.
Usually resistors and PNP or NPN transistors remain good so usually in the computer world, potentially CRTs which I am not an expert on may not always need other components to be swapped out. The problem, as we all know is ESR or resistance actually building up inside the electrolytic itself.
Anyway, thanks for sharing!
Usually resistors and PNP or NPN transistors remain good so usually in the computer world, potentially CRTs which I am not an expert on may not always need other components to be swapped out. The problem, as we all know is ESR or resistance actually building up inside the electrolytic itself.
Anyway, thanks for sharing!
Thanks for sharing this list! -- I went ahead and purchased the caps from the mouse project and replaced the signal board and neck board, Unfortunately the sweep board I just didnt.
The reasoning behind is because the caps on your list are rated for 85c which are fine for the signal board, but the neck and the chassis board they come originally with 105c rated caps
Yes I know that they will just work but on the long term that might not be the case
. The signal board caps are fine at 85c but the neck and the Sweep board require 105c rated caps. Hope this helps someone in the future
One interesting thing I have found is that sometimes 85°C rated caps have lower ESR than 105°C. I've never quite figured out why, but it has often been the case when I swap out caps for old electronics. It then becomes a question of which is better. Longevity with higher ESR or lower ESR. The decision would then center on how hot it gets inside that enclosure, and you would need to consider the inside temperature in the winter and summer too.The signal board caps are fine at 85c but the neck and the Sweep board require 105c rated caps. Hope this helps someone in the future
Your post is dated Dec.1, 2021. Today is Dec.16, 2024. Just curious... Did you ever get around to recapping yours?
If it measured 85°C with a fan, I would be very surprised! Probably measures in the 40's, but you would need a thermal camera or maybe a cheap IR thermal meter to check it more accurately. Thermal cameras are neat because you can point them at the whole circuit board and see how hot certain components get. In this case, knowing how hot the capacitors in question are after 1 hour of the monitor being on would be very useful info. But unless they are right next to something extremely hot on the circuit board, I suspect those caps may be quite similar to the internal ambient temperature. However, with a thermal camera, you would need to remove the case plastic. But in order to get an accurate measurement, you would have needed to have kept the case together as it heated up, then quickly remove it and test. Even then, a lot of that heat will escape when the case is removed.
The thing about ESR is, lower is often better, but not always. I really don't know what all those caps are doing. If there is a switching power supply inside, then more care must be taken because some caps need to have a minimum ESR for the power supply to be stable. I know this from recapping vintage PSUs like the Hard Disk 20SC "SONY" branded PSU. Yet other capacitors ("bypass caps") are just there to prevent voltage sags, and those benefit from low ESR. You then have yet other caps used in filtering circuits, and sometimes ESR matters on those. All said, just going with "low ESR" isn't necessarily a magic cure. When in doubt, one should probably just go with the stock capacitor's ratings, including temperature (since that impacts ESR).
But one other thing complicates matters further. Modern caps tend to be smaller than those you find in vintage 1980's electronics. Not always, but many times. And the physical size change has an impact on capacitor characteristics. In some cases, I've found the stock caps, which are physically larger than modern caps, actually have lower ESR (even being old) as compared with physically smaller replacements that I have purchased. So what I now do is choose the same capacitance, but I go with a higher voltage, such that the replacement cap is about as physically large as the stock cap. That often works out to the ESR being about the same as what the stock cap was new.
Yes, I know what you're thinking. Recapping is a bit complex! But much of the time, people recap without deep thought and still find success. I am just talking about "what is best." And sometimes that's a hard call.
By the way, is the fan loud? If not, just leave it. If it is loud, a quiet Noctua might be easier on the ears.