Portable wavy screen and sleep issues

[flag_day]

I'm trying to revive my Portable M5120. The screen has developed a sort of wavy horizontal flicker, faint but noticeable.

Sometimes, I need to push both buttons on the side before it will start up. And sometimes, I have to push them again before it will wake from sleep.

I get no error messages, and so far it has always started, one way or another.

It has the original Conner HD, and I rebuilt the battery with a 6V 5A TR5-6A Tempest AGM from batteryspec.com (about $20 shipped--fits easily and connects simply).

Any suggestions as to the cause and solution to these issues?

My guesses--something in the video circuit and hard drive format or end-of-useful-life...

 

[techknight]

capacitors. has it been recapped?

 

[flag_day]

Aha! Thanks...no, it's never been opened since I bought it new. I found that technique discussed here, and looks like something I could tackle.

Also discovered the floppy drive won't format disks and gives read errors. Does it need cleaning, adjustment, or replacement? What drives fit this computer? I have some old ones from some Quadras and Performas.

 

[techknight]

apart from blowing out the dust and cleaning the heads, there isnt much you can do...

however, at the same time, if the power supply to the drive is noisy from bad capacitors, youll have errors trying to read/write the disk.

Life story: (i know, people hate these). I have a macintosh LCIII. the disks started giving me trouble, read one disk in another machine worked fine. read it in the LCIII gave me unreadable error. but sometimes it worked. I recapped the few capacitors that were on the LCIII system board. everything is just peachy once again

when tackling a capacitor job, BE EXTREMELY CAREFUL!!!!!! the capacitor electrolyte when it leaked over time, it deteriorates the glue that holds the copper to the actual circuit board, so in MOST cases, not all, the pads will pop off the board and rip the trace in the process during removal, and the heat of the soldering iron only accelerates the situation. I use snips to cut the capacitor at the "ring" part toward the bottom, while applying downward pressure, because the mini dikes will try to squeeze the cap and force it to pull up before it actually "cuts" it. Without downward pressure on cutting, it could cause the pads to come up with the leads. thus ruining the macs day, and your day as well..

then once it cuts away you can just snip away vertically at the rest of the cap until only the pins and the capacitors seat remain. then you can just remove each lead one of the time off of the board with the soldering iron. Since the cap has been cut away, there is hardly any resistance to get in your way to remove the leads from the board via the iron. The seat will come up with it, leaving only the pads for the new cap..

Take some flux remover, or very fine tiny bit of alcohol on a q-tip to remove the nasty excess leaked electrolyte.

So if you feel uncomfortable in the slightest, just stop. and there are great more in-depth tutorials and there are people here that offer the service to you for a nominal charge, or even free depending on who offers their services.

 

[H3NRY]

Old capacitors can cause both problems due to noise on the power supplies. Loss of sound is another common symptom. Nearly all these old girls need to be recapped by now. If you can handle a soldering iron, the procedure isn't difficult.

 

[naryasece]

Is the flickering still a problem? I find on my portable, if the contrast is set to some value other than the min or maximum, the screen flickers. I thought it was the screen alternating between two contrast levels to create the desired level. Setting the max or min contrast makes the flickering go away.

 

[shred]

Likewise: my backlit portable has always had a few brightness "steps" that are no-go areas because they make the backlight flicker slightly. It seems to vary a bit with temperature too - after the machine has been on for a while, the problem diminishes.

However, the machine recently developed a nasty habit of blinking the backlight on and off. Am in the process of replacing the electrolytic capacitors on the logic board - hopefully this will fix the problem. The backlight inverter board has a couple of electros on it, but both are in good order and the heavy lifting appears to be performed by a polyester cap, so i doublt the problem is on the inverter board.