arm chair diagnosis needed

[cspgsl]

I have an R40, XPP full up to date. Two months ago I replaced the CPU fan and all seems fine in the heat department.

Today I turned it on and after a period the LCD displayed vertical black, white and red lines across the entire screen. They were very narrow... possibly 20 per inch. I could see the cursor and the mosue worked. I clicked on the start button location and the start menu appeared although nothing was legible, all I could see were the lines.

I plugged it into a CRT monitor and it did it once again although it has now been a couple of hours since it last did it.

A friend suggested it could be the inverter card but due to time restrictions he couldn't offer any further explanation.

Can anyone give me any ideas as to what I might look for or how I might test the video components (if indeed that is it)?

Thanks

[tomh009]

I plugged it into a CRT monitor and it did it once again although it has now been a couple of hours since it last did it.

What do you mean? Did the external monitor display the lines, too, or only the built-in LCD panel?

[cspgsl]

The CRT presented the lines. The LCD was off at the time.
The first time it did it the LCD was the only screen in use.

[tomh009]

That's not good ... the video chipset on the motherboard is not working. If you can't get it to display properly (warm, cool, cold, anything else) you may have to replace the motherboard.

[rkawakami]

A friend suggested it could be the inverter card but due to time restrictions he couldn't offer any further explanation.

The inverter is not your problem. The purpose of the inverter is to supply power to the fluorescent lamp (backlight or CCFL) in the LCD panel. It merely converts the DC voltage from the motherboard to the AC voltages needed by the lamp. In other words, if you are seeing something on the LCD that is at its normal brightness, that means the inverter is working properly.

Can anyone give me any ideas as to what I might look for or how I might test the video components (if indeed that is it)?

The problem can be internal or external to the video chipset. There should be a video diagnostic in the PC Doctor program for the R40:

http://www-307.ibm.com/pc/support/site. ... MIGR-46033 (diskette version)
http://www-307.ibm.com/pc/support/site. ... MIGR-56222 (CDROM version)

That diagnostic will test the video controller and memory, while at the same time showing the test patterns on the screen(s). It should tell you if the video controller and memory are working properly. Externally, the problem could be a broken or loose video cable, a problem with the LCD panel itself or a loose solder bond on the motherboard.

[cspgsl]

Thanks Ray and tomh.
All tests passed so I shall open the unit in the morning and check all of the connections.
Sure hope it's not the solder connection issue.
I'll get back to you

[rkawakami]

For your particular problem, since it is an intermittent one, if you don't find anything after you open up the system, then you should try running the PC Doctor video diags while moving the system around. Either gently flex each corner or try to repeat whatever movement which induced or fixed the video problem.

Also a clarification: since the identical eror shows up on the LCD and external monitor, that would tend to say it's a motherboard problem; probably the solder connection issue that you hope it's not .

[cspgsl]

Thanks Ray.
Try as I might I have not been able to reproduce the error since it first happened. All tests are OK while gently moving, flexing, pressing on the unit.
I had never realized how flexible these units were.
I am going to inspect the interior this morning for loose connections but wouldn't know what to look for re: solder problem.