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Toshiba T3100e and RAM video

A

andromeda92

Experienced Member
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Hi,
I have the toshiba T3100e/40 and I wanted to know where is the location of the video ram on the motherboard?

I have a problem, there are vertical lines on the plasma screen.

I looked at the power supply, it is correct and works well, it is clean, no faulty capacitors and there is power supply for the hard disk and for the motherboard.
I also cleaned some circuit in case it was oxidized.

I checked the RAM, everything is ok.

I tried the CGA video output on a CGA monitor and it didn't work.
Can I assume it's the motherboard?

The bios version is 3.0.
When I turn on the T3100e, it does not boot, the problem is before booting, there is just the disk which is powered and the green led of the power supply which is light green.

I think the probleme is ram video may be.

In the manual I did not find where was the video ram

Thanks for your help.
 
andromeda92 said:
I tried the CGA video output on a CGA monitor and it didn't work.
Can I assume it's the motherboard?
Click to expand...

I doubt it’s video RAM. Lines on those Plasma screens is almost always a problem with the screen itself, although I guess if the machine isn’t even booting it could be something else. More likely in that case is the entire video system isn’t being initialized.

Anyway, according to this page:


You have to hit Fn+End to switch to external video, it’s not enabled by default. From your description of there just being lights stuck on with no drive activity I will be kind of surprised if it works, my guess is the machine is “bricked”, but you can try.
 
I have tested Fn+End, it don't work, it's as if the motherboard is not working, or maybe the intel 286 CPU.
 
There's a description of a Youtube video that says CTRL-ALT-END also works as a switch to the external LCD, presumably that's an alias for an external keyboard, but, yeah, good luck with that. Are you getting any beeps that would indicate the BIOS code is running at all? If not, well, yes, it's probably "the motherboard", or possibly the power supply, but beyond that you're basically in the dark. My gut feeling is the *last* thing it's likely to be is something like the 286 CPU itself.

Generically speaking, old Toshiba laptops turning into bricks is a fairly common problem, across a wide generational swath. (I have a bricked 486 Toshiba in the garage junk box with the classic symptoms; the power light turns on but that's about it. And even the old Toshiba XTs like the 1100 will go all comatose for non-obvious reasons.) Maybe someone can suggest a common cause for the plasma-era ones, but until you get at least a BIOS beep trying to swap out the CPU or video memory is seriously jumping the gun.
 
I have no beeps.
I don't know if it's possible to change the CPU.
What type of CPU is it? CLCC or PLCC?
How to remove the CPU on this model?
 
Page 2-12 of the T3100e's maintenance manual (at [here]), indicates that as the power-on self test (POST) progresses, 'status' codes are sent to the 'PRT/FDD connector on the back of the unit'. The modern device shown at [here] will reveal the codes, assuming that the T3100e is getting as far as starting the POST. Note the important text of, "and set the A-B-PRT switch to PRT position."

However, if I compare the status codes (table 2-2) to the possible on-screen error message shown in step 6 on the previous page, there is some correlation. It appears that the first thing that the T3100e's POST does is to do some basic video initialisation, i.e. before any tests. For example, if the CPU flag register test fails, the last status code shown would be 01, and displayed on-screen would be 'CPU flag register error'. So if there is an on-screen error, what is the point of the status codes? I guess, if 01 (presumably meaning that test 01 has started) was the last shown status code shown, and there was no on-screen 'CPU flag register error', it would mean the POST 'crashed' during the CPU test.

(BTW. My use above of the CPU flag register test as an example, is just that, an example. I'm not suggesting high probability of a CPU fault.)
 
There is no beep on startup.
It doesn't make it to POST.
The A-B-PRT switch is set to PRT position.
I will have to find a POST diagnostic card on parallel port.
 
andromeda92 said:
It doesn't make it to POST.
Click to expand...
We should not discount the possibility of multiple faults.
For example:
1. A display related problem that results in nothing ever being displayed on-screen, plus
2. The POST is in fact starting, and then stopping part way due to another fault.

andromeda92 said:
I will have to find a POST diagnostic card on parallel port.
Click to expand...
I think it's a good idea. It is cheap and could be revealing.

andromeda92 said:
The A-B-PRT switch is set to PRT position.
Click to expand...
Required for operation of the parallel port POST card, not computer start-up.
 
If nothing is showing on the plasma screen I should at least see something on the external screen, but that doesn't work.

I'm not sure the post starts, because I should hear a beep or the memory scrolling on the speaker as I usually hear.
 
andromeda92 said:
I'm not sure the post starts, because I should hear a beep ...
Click to expand...
In my experience, the POST beep is usually at the end of the POST. For example, in the IBM PC family, no beeps can happen until the POST has got to the point of initialising the circuitry involved in sound production.
 
andromeda92 said:
If nothing is showing on the plasma screen I should at least see something on the external screen, but that doesn't work.
Click to expand...

Since you have to explicitly enable the external monitor port on these machines I would suspect that the machine has to make it completely through BIOS initialization, or nearly so, before it's going to start reading the keyboard looking for the external monitor keyboard combination. So I would guess if you have something really low-level breaking you're not going to be able to see it on the external screen, even if it's something that would appear on the internal one.

modem7 said:
In my experience, the POST beep is usually at the end of POST. For example, in the IBM PC family, no beeps can happen until the POST has got to the point of initialising the circuitry involved in sound production.
Click to expand...

The service manual for this machine has a list of the codes you'd expect to see on the parallel port starting at 2-12; there's a table of "normal" codes, followed by the error codes. IF Table 2-2 can be interpreted as being "in order" with regards to the tasks being executed at POST the first phase of "Keyboard Initialization" comes after a bunch of other things... one of which, coincidentally enough, is "PIT Channel 2 test and initialization", IE, testing and enabling the thing that makes sound. So if we choose to go way out on a limb that kind of suggests that the machine should be able to beep before it can read the keyboard... and it's not beeping.

That said, the manual doesn't say anything about beeps other than the boot-time beep, so it's not exactly clear if it would be fair to expect this machine to produce audible beep codes like most PCs do. Do they in fact make any noise, or do you have to have the LED dongle thing to get any hints?
 
In the meantime I will order the 8042 for the keyboard and the cpu, I will test all this within 15 days when I receive them, I will also receive within 1 month the dongle for the diagnosis on parallel port coming from China and I will know where does the problem come from.
Thank you for your help and explication.
 
There is a T3100e/40 video at [here]. At about 3:40, it shows no beep until a few seconds after the POST's check of RAM. Possibly the norm of {end-of-POST before OS boot is attempted}. So we definately know not to expect a beep at the start of the POST.
 
andromeda92 said:
In the meantime I will order the 8042 for the keyboard and the cpu, I will test all this within 15 days when I receive them, I will also receive within 1 month the dongle for the diagnosis on parallel port coming from China and I will know where does the problem come from.
Click to expand...
If we assume that your computer is not getting to the point of starting the POST, one possibility is corrupted BIOS ROM/s. I see that at [here], member MikeS provided an image of the BIOS ROM's (from his computer?).

Are you aware that an 8042 you purchase may not be suitable. It might be unprogrammed, or programmed with code for something else (like a microwave oven).
 
I had a similar problem on a 486, but I got to the post, the keyboard didn't work, and changing the 8042 it worked, but I didn't know the 8042 could be programmed.

For the bios, I tested with the original bios which worked fine before, and the 3.0 bios which worked fine before, and I have the same problem.

the 097b and 098b bios image is the original bios that I originally had.

as you say, my computer is not getting to the point of starting the post.
 
I think, generally for a computer that fails before the post is either the CPU, the motherboard, or the RAM
 
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