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driph
March 4th, 2020, 11:21 AM
With the GRiD laptops that had several hardware display options, is swapping out one for another simply a matter of replacing the display and its power supply in the case? Installation-wise, are there any other differences between the lcd, plasma, and electroluminescent displays?


(related, if any of you have an extra working 1520 plasma or electroluminescent display, let me know!)

Dagwood
March 4th, 2020, 12:59 PM
The complexity depends on if you're swapping out the entire lid or just the display panel within. The Gas Plasma lids have physically different brightness adjustment than the other display types, which have multiple adjustments. I think you would be hard pressed to swap a plasma panel into an LCD lid housing without some hacking to make it work, plus making it look good. The CGA GridCase 1520 has a 'video card', for lack of a better term, with a Yamaha driver that is capable of output to various types of displays. There are two IDC style headers on that card with the smaller one being used to interface a Gas Plasma display panel and the larger for others, so the supporting hardware appears to be the same inside the computer base. Swapping out an entire lid is probably the most reasonable tactic as long as they are both CGA. I'm not sure if the BIOS is display type specific but BIOS can be replaced so that wouldn't necessarily be a deal killer.

Klyball
March 4th, 2020, 02:38 PM
Depending on the unit going from lcd to plasma is easier as you eliminate the high voltage trans, in my 1550sx i can swap back and forth the plamsa has a little 2 pin connector power plug the lcd has a removable extra power board.

Qbus
March 5th, 2020, 05:07 AM
I have swapped LCD and Red Plasma without issues. The thing is I always swapped the entire display assembly after separating the display from the base. You also have to swap the video driver card but thatís easy. You just have to stay within the same family of laptops, 1520/30 or 1550 being they have different sizes but know I have done this in the past and it works.
Just changed a 1550 that had an LCD with flakey side lights to a Red Plasma display being now days the Red display is a lot more cooler looking. Think the Grid DOS has a color mapping program that allows you to optimize how the display represents different colors.

My 1550 with Red Plasma that I use for programing Motorola Radios. Had the LCD display at first but the Red display is way cooler looking and the old Motorola application is simple text only and refuses to run on anything beyond a 486 so the 386 in the 1550 works great for this.

59554

Dagwood
March 5th, 2020, 01:13 PM
Qbus, that looks really nice.

driph
March 5th, 2020, 04:09 PM
Thanks for the info, everyone, that really helps.

I've got two 1520s that I'm restoring (one yellow lcd, one blue lcd), and the second has some serious delamination. I may attempt to replace the surface to repair the display, but I'd still love to get a plasma or electroluminescent onto one of them and use it as a mostly dedicated somewhat distraction free writing laptop.

Now if only the keyboard switches had a better feel to them...

Dagwood
March 14th, 2020, 10:12 AM
Also, you should have to change the computer's internal DC-DC power supply too. 15XX models fitted with plasma screens have a PSU that outputs 33VDC for the display. LCD equipped models output 100VAC for the EL backlight. Both power supplies are very different... well, at least mine are. There were so many variations in these systems perhaps other configurations exist too.

Paralel
April 5th, 2020, 09:36 AM
Thanks for the info, everyone, that really helps.

I've got two 1520s that I'm restoring (one yellow lcd, one blue lcd), and the second has some serious delamination. I may attempt to replace the surface to repair the display, but I'd still love to get a plasma or electroluminescent onto one of them and use it as a mostly dedicated somewhat distraction free writing laptop.

Now if only the keyboard switches had a better feel to them...Delamination will be the death of me. I can't tell you how many decent LCD's I've lost to this. I'd swap to plasma just to avoid this, plus, as said above, it looks cool.

Do the old school plasma suffer from the same issue as modern plasma, being that their brightness degenerates with time?

Electroluminescent displays, as far as my understanding of solid state displays go, are essentially immortal. I wish more displays used them. Does anyone know why they weren't more popular? Too expensive?