The Uncommon LED-backlit T500

[TPFanatic]

read-edid IDs the panel as the LP154WX7 (TL)(A2), also known as LEN4057. It has typical poor TN viewing angles and brightness is rated at only 220 nits, which is quite dim, and why it fooled me all this time. What should have given it away was its instant-on/off backlighting and generally even backlighting side-to-side, whereas old CCFLs may be dim in the middle of the LCD on a cold-start. This LED panel does have a narrow shadow around the panel-edges, though.

This rare fossil has been under my nose for 8 years, and I didn't realize this until taking the poor thing apart to try and upgrade it with WUXGA. Now that I know what it is I have to leave it stock haha.

[ibrazhko]

What do you think is better?

1) LED WXGA (yes, LED, but terrible viewing angles, dull colors, super grainy resolution for 2023)
2) or CCFL WUXGA/WSXGA+ (great viewing angles and resolution, good colors, but inherently dim and prone to get even dimmer with time)

[axur-delmeria]

At least the WUXGA's backlight can be upgraded to LED. Having a 15.4" screen with only 1280x800 pixels is a waste of display space.

[unixed]

What is interesting, assuming this uses the same BIOS update as the CCFL ones, is that there must be a way of identifying the panel (so EDID, presumably) and then selecting the appropriate dimming regime since the same incremental adjustments will not be appropriate for the different backlights.
If it was easier to frankenpad the T500 it would be even more interesting ... moreover, it has 6 strings WLED without a B/L driver, so the "inverter" probably has the driver. As if that wasn't exciting enough, the signal interface is LVDS (1 ch, 6-bit), 30 pins connector.
At the least I would look for a high res panel with a somewhat matching datasheet, be prepared to edit the EDID and look at how the switching mechanism works to output to eg. WUXGA (2ch, 6bit) and this.

[TPFanatic]

I believe you are correct about using EDID to recognize the LED panel.
T500 actually will misidenfiy the SHARP WUXGA panels used in old Dells, that are fantastic and popular upgrades for 15.4" Thinkpads, as LED backlit and you can get some funny dimming behavior in T500/W500 that will even light the CCFL halfway to completely off. T61 and older are unaffected.

[unixed]

I had a look at the BIOS upgrades for the T500 and found that it's TP-6F/7V with latest BIOS versions (that I could find) 3.18/3.20.
If you run dmidecode right at the top of the output you'll get your BIOS version, and it should start with either 6F or 7V.
The R400 and T400 also have these dual BIOS options, and it may also be because of the LED screen option. I don't know if they have the option, I know the T400 has a high nit daylight readable option, but that's a different animal, where the panel contains the dual-LED strip driver. Checked -- the T400 also has a similar LED B/L display option to your T500.
As things stand there's the possibility that you can't simply swich the entire lid from your T500 to another with a CCFL-backlight display and vice-versa without affecting function.

[TPFanatic]

My former daily T500 was a 2082-8ZU using the 7- BIOS, it had a CCFL 1680x1050. Most other T500 I dealt with had the 6- BIOS and CCFL screens. The LED T500 in this thread is a 2242 and has the 7- BIOS.

[ibrazhko]

6 or 7 in BIOS refers to the GPU (Intel only or switchable Intel+ATI), and has nothing to do with the screen

[TPFanatic]

I'll have to double check my 2082-8ZU I believe it has the 7- BIOS as a switchable model while the above 2242 with the 7- BIOS is Intel only, and most of the others I had with the 6- BIOS were switchables.

[unixed]

The switchable graphics is plausible since in that generation only the R500 and W700(ds) have a single BIOS update. The W700 definitely does not have integrated graphics and my R500's with discrete graphics do not have integrated graphics as an option. I searched through the BIOS code strings since my handful is not exhaustive and conclude that no R500 has switchable graphics, at least as a listed BIOS option.
However the X200 also has a dual BIOS update, TP-6D/7X, but does not have switchable graphics afaik; it does have an LED screen option.
For completeness the X200s has the same dual BIOS updates as the X200; the X200t and T400s both have single BIOS updates despite my opening assertion.

[micrex22]

What do you think is better?

1) LED WXGA (yes, LED, but terrible viewing angles, dull colors, super grainy resolution for 2023)
2) or CCFL WUXGA/WSXGA+ (great viewing angles and resolution, good colors, but inherently dim and prone to get even dimmer with time)

Technically, LEDs get dimmer as time progresses as well. It's just when their life is up they usually just fail completely.

It's kind of a tossup for a CCFL. I have a lot of CCFL displays that are still bright; assuming the bulbs last and don't spotaneously die, they may outlive me or the screen will fail in another way (like vinegar syndrome) or the machine itself will fail.