Newly recapped Powerbook 160, screen artifacts or typical passive matrix?

[ironhalo]

After swapping out the 11 caps on the screen with tantalum equivalents, and the 2 on the inverted board with electrolytic/polymer replacements, the screen on my newly acquired PB 160 has come back to life! Huzzah!

It does however still exhibit quite a bit of smearing/shadowing/ghosting (not sure the correct term), most visible from the edges/corners of any finder windows or dialogue boxes (see pics). Is this level of artifacts normal for this era of passive matrix LCD, or is there some level of disfunction still present? Honestly it's been so long since I've used a portable of this vintage that I can't remember if this is just how the passive matrix screens always looked.

Also, the brightness slider does not act like a slider at all, but more of a backlight on/off switch. From 0-10% the backlight is off, then from 10-100% it's on at constant brightness. No dimming whatsoever. I was a bit concerned but then I found this thread where others have said this is normal for early 1xx series powerbooks? That's a bit surprising because I thought I remembered my PB 150 in college having some level of actual variable dimming, but again, it's been a really long time.

TIA!

 

[finkmac]

this looks like normal passive matrix ghosting to me, adjusting the contrast can help

 

[ironhalo]

this looks like normal passive matrix ghosting to me, adjusting the contrast can help

Thanks for confirming. I've read that adjusting the brightness can also help, but I don't think they meant turning the backlight off, which is the only brightness 'adjustment' I seem to have.

 

[jmacz]

The artifacts seem normal.

As for the dimming, I need to check my 160 when I get home but from my memory, there was “some” dimming but not much in terms of a smooth adjustment of varying brightness. It was off, one or two mid levels, and then full on if I remember correctly. But I thought there were some intermediate steps between off and on.

 

[ironhalo]

It was off, one or two mid levels, and then full on if I remember correctly. But I thought there were some intermediate steps between off and on.

Yes that's what I vaguely remember from my 150 back in the day. It was never a smooth dimming action, but it certainly wasn't binary. Makes me suspect some other component on the inverter board is no longer operating in spec and preventing whatever level of dimming was originally achieved.

 

[Byrd]

Very normal for PowerBook passive matrix, there should be some graduation of brightness on the dial; give it a good clean with solvent cleaner or maybe the aging CCFL that's all you get before it flickers off.

Being released a few years later the PB150 passive matrix display is of a better quality.

 

[Shaddam IV]

The fluorescent tubes of the powerbooks' screens dim over time. Get a new one and solder it in. Then you'll have a brighter screen, and you'll be able to dim it (somewhat).

 

[croissantking]

Seconded that the ghosting is normal for these.

Yes the brightness function should be adjustable; normally it goes from ‘off’ directly to ‘low’ then you have a bit of graduated adjustment up to ‘high’. Seems like yours is going directly from ‘off’ to ‘high’.

I have seen this issue on my own machines but it always goes away on its own, I don’t know the reason. It could be PRAM battery related, possibly. Or it could be a bad connection on the CPU daughtercard interconnect cable.

 

[dan.dem]

You already know that's the typical PowerBook base model ghosting of the cheaper passive matrix displays. I had it in my 5300 too.
Back then I used the pebbles wall paper available in the control panel (System 7.5 or newer if my memory serves me right) to reduce the lines quite substantially at least at the desktop.
Geometric patterns or blank white areas look much more disturbed by the lines as vivid pictures do.
However also the pebbles wall paper is in fact a repeating pattern, but a larger, more photo-like one.