Compaq Portable 386 display issue

[agentb]

Anyone happen to know what the cause of this screen anomaly may be? There’s some jumping around of the pixels at the top of the distorted column. Most of the display is fine but there’s a column towards the center of the screen that’s distorted.

 

[agentb]

A different example from graphics mode.

 

[MissArgent]

Dead columns are a pretty common issue with gas plasma displays - for some reason the Compaq Portable III I've seen are especially prone to problems. Unfortunately, in the case of my old one I never managed to learn anything interesting - just that it wasn't anything basic like a loose connector.

 

[granzeier]

That looks familiar!
I know that it's not related, but have you been able to get a display from the external VGA port?

By the way, many of those BAT files were just for me to quickly get around, and get work done. If you see a D-DRIVE\ directory, those files were copied to my RAM Drive (long time ago) and then they ran much faster. Many of those batch files depended on 4DOS.

 

[agentb]

Dead columns are a pretty common issue with gas plasma displays

Good to know - yeah I gave it a few whacks and no change so didn't seem like a loose connection.

 

[agentb]

That looks familiar!
I know that it's not related, but have you been able to get a display from the external VGA port?

By the way, many of those BAT files were just for me to quickly get around, and get work done. If you see a D-DRIVE\ directory, those files were copied to my RAM Drive (long time ago) and then they ran much faster. Many of those batch files depended on 4DOS.

Haha indeed, it lives! I don't have an RGBI monitor to test with unfortunately. I'm hoping to track one down, or get a converter, as I have an old Tandy 1000 that could also benefit from a CGA monitor.

I was wondering about the D-Drive -- thinking maybe you had an external disk, but a RAM drive makes more sense, gotcha. Had to look up 4DOS today as I wasn't familiar with it. Would be nice to hook this machine up to a wifi modem to get some connectivity going!

 

[granzeier]

I had thought that there was a DB-15 connector on the back, where you could plug in a VGA monitor, but it appears that I was wrong.

A couple things that may help:
1) "Detailed Features and Specifications" - https://minuszerodegrees.net/manual...tailed Features and Specifications (1987).pdf
2) "Compaq PORTABLE 386 Maintenance And Service Manual" - https://www.manualslib.com/download/273076/Compaq-Portable-386.html

 

[clearscreen]

Hi,

i've totally restored a portable 386 one.

There was some trouble on the plasma screen and i put some kf for contacts on chips (no need to do some resoldering like i've done in my logabax p1600).

Please allow me to warn about the plasma screen. You know i always take care and measure signals and voltages. Well compaq put some high voltage on a specific molex to the screen. And input voltage if i remember is kind of 100V or more. Same plug than molex hdd .... great design ...

So be very, very careful with video stuff with this computer if you open it...

Some photos

final aspect , cpu change from 386 to ti 486 upgrade and math copro , signal check , koeyboard cable rebuild from an old din keyboard , keywashing . rebuilind keyboard latch (broken as it was forced - oh by the way, there is an hidden screw under the brand sticker)

and finally some photos of the screen (in fact i've totally dismount all the computer - some brown dirt glued inside, so ...)

and it still work

Regards.