Jump to content

SE No Display :(


Recommended Posts

I recently purchased an SE w/ Superdrive locally for $30.  This computer has dual 1.44 floppy drives and has an internal 30meg HD (after opening up the machine it appears the HD was not apple OEM but added).  

 

The computer worked fine but had one annoying issue, that is the display would appear slightly jittery/wavy only while tasks were being performed.  I put about an hour or two of use on this machine to test it all out, everything else was fine ...including clear sound.  The display was stable when I wasn't doing anything, as soon as I would copy a file, load an app' or perform any task I'd see a bit of display jitter/wavyness.

 

So, after some reading online it sounded like it could be my power supply giving me trouble.  I was going to open up the power supply unit and check all the components and replace as necessary when instead I found a "tested to work" SE power unit matching the same model number as mine shipped for $15, this seemed like a better deal than the headache of identifying and replacing components.  So, this morning I opened up my machine and swapped power supply units.  I turned on the machine and everything seemed the same, clear sound but the jittery/wavy display (only during tasks) still persisted.  However, within a few minutes after having the machine on the screen developed about 5 or 6 horizontal lines along the top of the screen and the screen went very bright.  I turned down the brightness via the brightness control knob on the front of the machine and that worked for a second, but then the screen got really bright again, to the point I could barely see anything on the display.  I could not see the menu on my desktop so I did a hard shut down via the power switch. I opened the machine checked everything visually, just a quick inspection ...verified that my power supply ground wire was connected, etc... put machine back together and turned on, everything works I get a chime, HD is spinning, fan is on, but no display at all (black no display).

 

That is where I am at now (had to go to work).

 

----------

Please help! 

 

Here is a thought:

1) I had a loose connection from my CRT to the analog board which became worse when I openeded the machine and swapped power supplies.  The connection became completely severed rendering no display.  (yet would this account for the bright screen prior to it going dead)?

 

 

thanks in adavance-

Edited by eR1c
Link to post
Share on other sites

Something in the analog board died. I doubt it was the powersupply since nothing changed when you replaced it. Probably needs to be recapped. I notice that once in a long while my SE will do that jittery screen thing. Usually only for a few seconds. Sometimes it would happen when I insert a floppy. But I've only seen it do it a few times. I've heard this means the analog board needs new caps. Mine probably will be fine for awhile as it rarely shows screen jitters. But it is showing it's age (as there is screen burn in enough that I can see a faint shadow of the menu bar. It's not bad enough to where I could see the original desktop icons. Just the faint outline of the desktop. But it does indicate that the screen/analog board has seen a lot of on time).

 

I'll probably wait until after I get my SE/30 before I can afford to recap the analog board in the SE.

 

As for your issue. Definitely sounds like bad caps in the analog board. It was probably limping along due to the old powersupply being a bit on the weak side. Once you replaced the power supply, it probably accelerated the death of the analog board.

 

You should probably send that analog board off to someone here who can replace caps. I've heard uniserver is the go to guy for this. ;)

Edited by Apache Thunder
Link to post
Share on other sites

Re-cap the analog board, that is GREAT news ...that is easy for me to do, i've re-capped my Mac Classic II analog and motherboard w/ 100% success and have soldering experience on many other non Mac related projects...I actually find re-capping fun (call me nuts).  Its slow but easy and gratifying work ...I usually put the music on and enjoy a beer while I am doing it. 

 

...so here is a question, do you think that the display going dead just after the power supply swap was coincidental? Could turning the brightness knob up had something to do w/ pushing a dying cap over the edge? I say that because initially after I put everything back together my screen brightness was off (I probably jostled it while swapping power supply units) and was fiddling w/ the brightness just prior to the screen issues...  

Link to post
Share on other sites

The powersupply swap could have accelerated it's demise. The old power supply might have had sagging voltage levels and once replaced and voltages brought back to spec, dying caps probably roasted at a much faster rate. Hard to tell since you didn't have that SE for very long. It could have just been a coincidence who knows. :p

 

But truth be told, psu swap or not, sounds like your Mac would have died like this either way. Yeah recapping it "should" fix it. If not, then solder reflow might also be needed. I've heard that could also be an issue. But I've heard not as big an issue for the SE as it was with older fanless Macs and the newer Classic/Classic II line which also are known for failing analog boards.

 

Worst case scenerio is a transistor or some other part on the analog board died. Sometimes running a mac with bad caps can have some bad consequences. Hopefully all yours needs is new caps.

Edited by Apache Thunder
Link to post
Share on other sites

okay, i am a total dumb a@@!

when I swapped power supplies I did not fully engage the cable that connects the CRT to the AB.  Upon opening the machine this evening (I was going to located cap C15 and replace), I noticed that the cable was not connected and just dangling.  I plugged back in, started up and all is well again.   

 

So this problem is solved and was user error.  Guess you can't get a display if it's not connected to anything! :0

 

Thanks for all of your help!

Link to post
Share on other sites

Caps in the psu, caps on the ab

 

Caps in the replacement psu

 

C15 is a big problem on these ab's

3.9uf , I replace with 400v

 

Se's are also known for a transistor going bad on the video board.

 

Wavy video is always shit psu.

Recap, 15 dollar replacement will need caps aswell. replacement theroy is moot, same situation, Dead output filter caps in your smps.

Edited by uniserver
Link to post
Share on other sites

 

 

lol Well that too could cause the issue. Did you see if the screen jitters still occur? If not I guess it was the Power Supply that was acting up then.

The problem is still present but much less.  Which leads me to believe it could be as simple as cracks/band solder connection of the CRT to AB connection.

So still looking into this...

 

 

 

Caps in the psu, caps on the ab

 

Caps in the replacement psu

 

C15 is a big problem on these ab's

3.9uf , I replace with 400v

 

Se's are also known for a transistor going bad on the video board.

 

Wavy video is always shit psu.

Recap, 15 dollar replacement will need caps aswell. replacement theroy is moot, same situation, Dead output filter caps in your smps. 

The PSU I believe is good, -I have tried 2, the original one and one that is verified to be working in another SE.

Caps on the AB ...possibly ...checking into that.

 

C15, yes, that is getting replaced this week ...even if not for good measure.

3.9uf, 400v --thanks! ;)

 

 

 

Recap, 15 dollar replacement will need caps aswell. replacement theroy is moot, same situation, Dead output filter caps in your smps

not sure I totally follow what your saying here, ...i kind of think i understand but having trouble reading / interpreting this sentence correctly.  Are you saying that if a recap doesn't solve my problem then ...dead output filter caps??

 

 

initially here is what I am going to try this week:

1) re-flow the connection of the 4 wires from CRT to AB 

2) replace C15

3) re-check / compare the power of both my power units to verify that indeed the psu is good (even though I was told it was)

...

Link to post
Share on other sites

Opened up the SE today,

wow, 2 of the 4 solder joints had significant cracks all around, one seemed to have a thin/hair line crack that made a full circle around the joint.  This was all visible w/ just my reading glasses.  Under the magnifying glass it looked horrendous.  So that was good to see, ...I got most of the old solder off I could and re-flowed new solder, put back together and problem is no officially solved.  Screen looks 100% stable.

 

While I was checking solder joints I noticed several other areas that looked like they had cracks too, so while I fixed that one joint I did a few others as well.  

 

That C15 cap looked good to me, but not quite as flat as I like to see these old caps.  It isn't puffed or anything, but just didn't seem quite as flat as the other cap's on the board.  Yet that may be me or just may have been how it was manufactured.  I just like to see the tops a bit concave to flat.  In any case I will order a replacement and re cap that one next time I have the machine open just for good measure.

Link to post
Share on other sites

 

 

Which solder joints had bad cracking? Was this on the analog board?

 

Yes, it was the 4 joints on the analog board.  Basically all I had to do was open up the computer, take off that white cover on the AB then inspect the back of the board's solder joints w/ a magnifying glass.  I found quite a bit of bad joints on that board actually and resoldered all the ones that looked cracked.  The 4 joints that go to the CRT were badly cracked, in fact one or two of them had a perfect crack that went the entire diameter of the joint... once I saw that I knew that this had to be causing trouble.  I tried to get as much of the old solder off as I could, but once i added the new solder the old seemed to melt together w/ the new and made a good clean joint.  My monitor is perfect now, no more wavy/jitteryness when its accessing the hard drive like previously. 

Link to post
Share on other sites

I fixed one of my SE's this year after it suddenly lost video completely.  I think it was C15.  No cracked solder joints that I could see.

 

Good work on the fix.  It is interesting to see how the community has changed when I joined over a decade ago...the supply of good parts was available and cheap!  So not much actual electronics diagnosis and fixing was happening, unlike today.  

 

I was glad to fix my SE because it runs 24/7 at my office...I have a clock program running on it.  It is a very menial task for such a fine machine, but at least it is still in use!  I'm hoping that someday the nasty case of screen burn-in will un-burn itself over the years too.

Link to post
Share on other sites

Do me a favor and inspect the plug for the deflection yoke. My FDHD was doing the same thing and discovered that a poor connection in one of the pins had built up a high enough resistance connection that the plug was crispy and the pin and socket had corroded up. Wiggling agitated the jittery condition.

Link to post
Share on other sites

 

I fixed one of my SE's this year after it suddenly lost video completely.  I think it was C15.  No cracked solder joints that I could see.

 

Good work on the fix.  It is interesting to see how the community has changed when I joined over a decade ago...the supply of good parts was available and cheap!  So not much actual electronics diagnosis and fixing was happening, unlike today. 

 

-Hey, C15 is what I was going to look at next, but didn't have to.  However I would like to have a replacement on hand for C15 as I hear that this one goes out often on the SE's.

Do you recall what type of cap' you used to replace C15?

Would this be suitable:

http://www.mouser.com/Search/ProductDetail.aspx?R=ULD2G3R9MPD1TDvirtualkey64700000virtualkey647-ULD2G3R9MPD1TD

 

It is kind of nice in a way that we can fix our computers piece by piece rather than replacing entire components, ...makes this hobby more fun in my opinion.  Otherwise it would be too easy!

Edited by eR1c
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...