68kMLA Classic Interface
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| Macintosh SE/30 power on issue | |
| Posted by: Plumpeken on 2019-03-14 20:15:56 I just got a Macintosh SE/30 for a good price ($35) it's in great shape but non functional. I have worked on many computers in the past but never anything this old, I thought it will be a fun project. This issue is that when it's powered on it sounds like the speaker is beeping, the fan revs up and down only a bit, I could only notice the change in speed when the back was off, the screen also flickers with a white streak in the middle corresponding to the "beeps" but the screen completely turns off after a few seconds. I took the computer apart. Of course I made sure to discharge anything that could still have some charge left. I though this could be a power supply issue because the floppy connector on the back has an extremely inconsistent voltage, ranging from 1-3v (should be 5v) after taking the power supply out I notice that a component in the power supply doesn't really seem right, I think it's a transformer. (picture below). However, when I power on the supply and measure the voltage right from the connector with nothing connected, all the voltages are stable and correct. Never working on any of these before I'm not sure if the analog board has anything to do with it, or maybe these power supplys can be unstable under load. I haven't seen any other sine of damage anywhere on the computer. The power supply is an Astec It's also worth mentioning that the guy I bought it from said when he powered it on recently it seemed to work fine, but the screen was a bit blurry, when he restarted it, it stopped working. I've never worked with CRTs so I don't really know what would directly cause that. Any help would be appreciated Update: I was not able to upload the pictures, so here is a google drive link: https://drive.google.com/file/d/1JdvrQbJOif34zIA7_-DEcJnwOTkhsu6e/view?usp=sharing https://drive.google.com/file/d/1LwFgzlAJrZpTQdfurck7HBZNo-tGrYtj/view?usp=sharing https://drive.google.com/file/d/19sWl-Bk_I5xgefFS-sYHVv1J_DWkGvSy/view?usp=sharing Let me know if these links are broken | |
| Posted by: dochilli on 2019-03-15 06:41:48 Most (all) analog boards and mainboards must be recapped. The SE/30 has a psu on the analog board and this must also be recapped. So this is the first step to go. Take the battery out of the main board. It can cause damage of the boards. I can not see your pictures... | |
Posted by: Plumpeken on 2019-03-15 06:58:19Most (all) analog boards and mainboards must be recapped. The SE/30 has a psu on the analog board and this must also be recapped. So this is the first step to go.Thanks for the reply, I managed to upload one of the pictures. I understand that I should recap everything, but I think this transformer could be the intimidate issue. What do you think?  | |
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