Macintosh Plus no display, any ideas how to fix it?

[Dipper184]

Hi everyone,

I have Macintosh Plus, the screen disappears after some time and I usually just slap the side but now it doesn't work the screen Is completely blank (yes I turned the brightness to maximum amount alas nothing changes). Does somebody know how to fix it or what causes it?

 

[trag]

Pin 1 on the connector for the cable that runs between the logic board and the analog board needs to be desoldered and resoldered at the analog board side.  Pin one is the pin on the end of the connector next to the blank position.

 

[dochilli]

I resoldered all pins of the cable on the analog board and that solved the problem.

 

[trag]

Glad to read it.   Am I looking at two User Names for the same person, or two users who live near each other, or two different Macs?

 

[Dipper184]

One more thing, how do i disconnect anode cap? (I already discharged crt), problem is that when i try to pull it out of the crt my fingers just slide off...

 

[tanaquil]

Some people say you can just pinch the rubber neck of the cap with your fingers, but that never works for me. I like to bend the edges of the cap upward (makes it easier to see what I’m doing), then GENTLY push one metal leg inward with the tip of the discharge tool until it pops out easily. Pressing nearer the top of the leg seems to work better than pressing the bottom, no idea why that is. 

 

[Bolle]

Grab the cap and move it sideways until one of the legs disengages from inside the CRT, lift up the disengaged side and move the cap sideways into the opposite direction to get the second leg loose.

Needs some twisting and wiggling sometimes but eventually it will come loose. It gets easier once you have done it at least once

 

[Dipper184]

Some people say you can just pinch the rubber neck of the cap with your fingers, but that never works for me. I like to bend the edges of the cap upward (makes it easier to see what I’m doing), then GENTLY push one metal leg inward with the tip of the discharge tool until it pops out easily. Pressing nearer the top of the leg seems to work better than pressing the bottom, no idea why that is. 

Thanks! it worked |)

 

[dcr]

I have a similar problem but before I go wild with the soldering iron, I thought it might be best to give some details to double-check first.  I initially bought this Mac Plus with the seller saying the screen didn't work.  I figured that was fine because I could always use it as a parts machine.  The computer was shipped to me and, upon arrival, I gave it a test boot just to check things out.  The machine gave a boot chime.  I tested the brightest control and found it was at the lowest setting.  Once I adjusted the brightness, the screen was fine.  Some time later, when I booted, the screen didn't display.  I tapped the side of the machine and the screen came right on.  I figured something must have been loose and shipping the machine shook it into place but after sitting for a while maybe it came loose again.  It worked that way for a while; if the screen came up bank, just tap the side and it displayed like normal.  Today, tapping the side only makes the screen work when I tap it.  It doesn't stay on like before.

Will resoldering Pin 1 as described in this thread fix that or do I need to be looking elsewhere?  Or should I resolder all the connections on the analog board?

Thanks!

 

[trag]

No display, restored or intermittent with left side tapping, is always pin 1 on that connector.   There's probably some exception, but so rare.

 

[dcr]

No display, restored or intermittent with left side tapping, is always pin 1 on that connector.   There's probably some exception, but so rare.

I need to try again tomorrow.

After failing on my SE/30 repair, I was hoping for a win and thought this would be an easy one.  I took the Mac Plus apart and checked all the soldering points on the analog board.  Everything appeared solid.  But I redid the soldering joints on the connectors anyway.  Removed and put new solder on pin 1.  Reassembled and powered up.  Bingo!  Screen works.

Shut down and carried the Mac Plus to the desk where I keep it.  I hooked up the mouse and powered it up and . . . nothing.  Tapped the side and the display came up.  At least it's full screen rather than partial as it had been of late.  Shut down and power back up and same result.

Maybe I'll get a chance to try again tomorrow.

 

[CC_333]

I had one like that, where no matter *how* many times I soldered, desoldered and resoldered those blasted connectors, it would still behave the same way (intermittent video until tapped on the side).

I think I eventually gave up and got another analog board that didn't have the problem (it's been ~8 years since I did this, so I don't remember much of it anymore).

Maybe start checking places other than that connector? There are numerous other solder joints that, when cracked, can manifest this way.

c

 

[trag]

IT's kind of embarrassing I had forgotten this but CC_333's comment reminded me.    I actually had/have one of those exceptions.   I didn't think of it because I've seen the pin1 problem many many many times before.   

But in the exception, the screen would cut out like yours does.   Eventually banging the side didn't do anything.   But if I powered up with the case off, and gripped the rear edge of the analog board and pulled outward until it deformed a bit, video would come back.

At the time (like 20 years ago) I was flummoxed.  Now days, this would suggest to me to remove the analog board and desolder and resolder pretty much all of the joints.   I might try examining it under magnification for bad joints, but those can be very difficult to spot.

 

[dcr]

I didn't get a chance on Sunday, but hopefully this weekend I'll get a chance to go over it again and hit every solder point.

 

[dcr]

I had the chance today to work on this again.  I looked over all the solder joints and I redid any that looked bad.  I resoldered all the connections on all the pins.  If the solder looked good, I just reheated and let it reflow.  If the solder looked questionable, I did new solder.

After checking and rechecking, I put everything back together and started it up.  Screen came up fine.  Tapped the side and the screen didn't go out.

Then I went ahead and moved it to the desk that it is temporarily calling home.  Set everything up and booted.  Screen came up fine.  Tapped on the side and no issues.

So far, so good.

Next test will be to see if it still works okay after sitting around for a day.  Then, I should try to boot it with a disk to make sure I didn't screw up anything else.  (Everything else worked fine before.)

Thanks everyone!

 

[dcr]

I know this is an old thread, but this is the same Mac Plus I resoldered this year for the same issue.

So, basically, it had display problems.  As I can see in re-reading this thread, I resoldered (and put new solder on) pin 1 on July 21, 2018 and redid the effort on July 28, 2018, after which point it worked fine.  Also, at the same time, resoldered anything that looked like maybe it needed it.

And it worked fine for about a year, until last Friday, July 12th, when it exhibited the same issue again.  On the 15th, I resoldered not only pin 1 but anything else that looked maybe like it could be problematic.  And I did remove the old solder and replace with new.  Truth be told, to my untrained eye and without a magnifying glass or anything, all the connections looked good prior to resoldering.  And it has been kept in an air-conditioned office for whatever that may be worth.

Any ideas what the problem might be?  I mean, if I have to resolder annually, I suppose it's not a major problem.  But, if there's something else that needs fixing that would mean I wouldn't need to perform an annual resolder, it'd be nice to be able to fix it and (hopefully) be done with that particular issue.

Thanks!

 

[Dimitri]

I know this is an old thread, but this is the same Mac Plus I resoldered this year for the same issue.

So, basically, it had display problems.  As I can see in re-reading this thread, I resoldered (and put new solder on) pin 1 on July 21, 2018 and redid the effort on July 28, 2018, after which point it worked fine.  Also, at the same time, resoldered anything that looked like maybe it needed it.

And it worked fine for about a year, until last Friday, July 12th, when it exhibited the same issue again.  On the 15th, I resoldered not only pin 1 but anything else that looked maybe like it could be problematic.  And I did remove the old solder and replace with new.  Truth be told, to my untrained eye and without a magnifying glass or anything, all the connections looked good prior to resoldering.  And it has been kept in an air-conditioned office for whatever that may be worth.

Any ideas what the problem might be?  I mean, if I have to resolder annually, I suppose it's not a major problem.  But, if there's something else that needs fixing that would mean I wouldn't need to perform an annual resolder, it'd be nice to be able to fix it and (hopefully) be done with that particular issue.

Thanks!

Hi dcr,

I have the same your issue, exactly!

i found the problem, after resoldered the connectors on analog board side, the screen comes up for a while but it turns off in about 10 seconds. Ok I moved the Mac and the screen comes up. The problem in my case is J1, after resoldered, still has problems and I found that the connector is a bit slack, when the Mac is on,

moving the connector with an insulated nipper, the screen goes off and on.

I am hoping the connector does not needs to be replaced because I am not able to insert the wire into it!! 

 

[Byrd]

Hi all,

I've just been doing the same thing!  A Mac Plus with no display (flickers on with a tap on the side) that tripped the mains power after 5 minutes.  Replaced the line filter capacitors on the analogue board which ceased it tripping power, but found the J1 connector, pin 1 plug was completely burnt out - I needed to rewire this cable directly to the board.  Then I thought something on J1 failed again, but it wasn't that, rather all three cable connectors on the analogue board were flaky and needed resoldering (with new solder).  So far seems good.

JB

 

[Dimitri]

Hi all,

I've just been doing the same thing!  A Mac Plus with no display (flickers on with a tap on the side) that tripped the mains power after 5 minutes.  Replaced the line filter capacitors on the analogue board which ceased it tripping power, but found the J1 connector, pin 1 plug was completely burnt out - I needed to rewire this cable directly to the board.  Then I thought something on J1 failed again, but it wasn't that, rather all three cable connectors on the analogue board were flaky and needed resoldering (with new solder).  So far seems good.

JB

Yes, this evening I resoldered the joke connector (power to crt) without success, so I replaced with fresh solder the J1 and now the Mac is going very well!