Jump to content
Sign in to follow this  
mattsoft

Macintosh SE with horizontal lines, no chime

Recommended Posts

I have an SE that when powered on does not make a chime and displays these lovely horizontal lines. Initial inspection of the motherboard looks good. Anyone familiar with these symptoms? Gonna check voltages next. Thanks!

IMG_3230.jpg

Share this post


Link to post
Share on other sites

Always start by re inserting the ram after cleaning each one with isopropyl alcohol. If that doesn't work try configuring the SE with 512k and check each ram stick by swaping them untill you get the machine working.  

Share this post


Link to post
Share on other sites

I cleaned the SIMMs and sockets. This SE has 4MB of RAM (4 X 1MB SIMMs). With the 4 SIMMs installed, I get the horizontal lines.

 

I removed the 2 SIMMs from slots 3 and 4 so it only has 2MB of RAM and I get a black screen. Swapping the 4 SIMMs around so that only the 1st 2 slots are filled always gives a black screen.

 

If I put 2 SIMMs into slots 1 and 3, I get vertical lines. This config shouldn't work, so I guess that makes sense.

 

Maybe I have 3 or more bad SIMMs. What I need is a working SE to start swapping parts. Will keep a lookout for one in the area.

 

Thanks!

 

 

 

Share this post


Link to post
Share on other sites

examine the pins underneath the mobo - might be bent in the way they cause short circuit. Sounds strange, but I had the recapped SE/30 with the same issue. 

Edited by CharlieFrown

Share this post


Link to post
Share on other sites

Well, I figured out why I was getting a black screen when only 2 SIMMs were installed. My SE logic board has the 150 ohm resistors at R35 and R36. On my board, R35 was cut and R36 was removed. I soldered 150 ohm resistor on R36 and put 2 SIMMs into slots 1 and 2 and instead of a black screen, I get the same damn horizontal lines. I swapped all 4 sticks of RAM around in those 2 slots and always got the horizontal lines. So either I have 4 bad SIMMs or it's something else.

 

I removed all 3 ROM chips, cleaned the pins and sockets and re-inserted. No change.

 

I also tested the voltages on the power molex into the motherboard. Everything looks good.

 

Checked all the pins on the bottom of the logic board and nothing appears to be bent or shorting anything.

 

At this point, I'm stumped. If someone has a working SE motherboard they'd like to sell cheap, I'm all ears!

 

Thanks!

Edited by mattsoft

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×