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Macintosh SE crt black after changing ram


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My SE FDHD has been working perfectly for almost a year now, however I recently decided to change the ram and after doing so I no longer get a picture on the crt but the machine still boots. Anyone know what might've caused the CRT to stop working?

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A few questions to rule out some things:

  • As nixontheknight said, if you removed the neckboard from the CRT, did you reconnect it?
  • When powered on, if you adjust the brightness knob does the screen go white with retrace lines (diagonal and horizontal lines) appearing on the screen? If so, the tube and flyback are working.
  • If you have another SE, can you swap this one's logic board into the second to verify it's actually outputting video?
  • Are all your power rails outputting the correct voltages? Too little power can cause some things to run and others to not; the CRT driver circuits on analogue boards will not drive the CRT if insufficient power is being provided to its transistors/ICs.
  • Have you recapped the analogue board?

Additionally, take a look at section five in the following link. While this link references an SE/30, the SE and SE/30 have interchangeable power supplies and analogue boards. You'll need a multimeter that can test diodes to diagnose what's described there, but it's a solid set of things to test.

https://www.jagshouse.com/classicrepair.html

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I'm not an expert here, but last time when I searched for 30 pin rams on eBay, a seller specifically stated that this pair doesn't not work well on Mac SE, and mentioned the number of chips per module. So you may also have to check if your mems are compatible with Mac SE even if they are all 30 pins modules and the speed matches the minimum for SE. 

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Can also just be a coincidence. 

 

I will try to get back to the former ram for a test, also, the SE has a jumper on the Logic Board to select increased ram size (if this is the case)

 

can be an issue with the A Board (same as the Plus, bad solder joint on the upper connector) can happen out of the blue. 

 

A ram issue will probably also lead to chimes of death at some point, but anything can be possible. 

 

Just my two cents...

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1 hour ago, bibilit said:

A ram issue will probably also lead to chimes of death at some point, but anything can be possible. 

 

The SE and prior (Compact) Macs do not have the Chimes of Death.

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The SE and prior (Compact) Macs do not have the Chimes of Death.

 

You are right, the Plus will perform a slow or distorted sound with bad Ram and probably Sad Mac codes as well (sometimes screen is black with only the blinking folder present), don't know about the SE, most are bulletproof, but yes probably a sad mac error at least with no particular sound whatsoever.

 

Never noticed that the Chimes came on later models...

 

Anyway, if the SE still boots properly, don't think is a Ram issue.

 

 

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