desertrout
Member
I'm trying to troubleshoot a non-booting Toshiba T1100 Plus and hitting my limit in understanding and ability as a hobbyist - but learning is one of the reasons I enjoy this hobby, so I'm hoping to get a little direction if possible.
The machine is new to me, and I received it in a non-booting state (i.e. despite using a good battery and the correct adapter, it does not boot). When turning the power on, the Power LED and CRT LED light (indicating good power, but the LCD is disengaged - which I understand to be abnormal at startup), but the machine does not appear to POST: no image appears via LCD or composite, no beep. The keystroke to select LCD does not do anything. I confirmed all switch, DIP, and jumper settings are appropriate (however, there are some jumpers that are not described in the docs).
I then recapped the power supply board, logic board, and display board, cleaned the boards and all connectors, but no change in symptoms. I have confirmed that the power supply board is providing the proper voltages. I did a quick visual inspection of the boards, and confirmed any suspicious traces - but I could do a more thorough inspection.
The PRAM battery has been removed and not replaced (god I hope this isn't the issue... or maybe I hope it is?).
However, as what sometimes happens while handling parts, I can cause a change in behaviour. I first noticed that - sometimes - while moving the display cable or the LED assembly while the computer was powered on, the CRT LED would turn off and the LCD would show all pixels... but nothing else would happen, it would just stay like that. This same thing now happens fairly randomly when powering the machine on - after a few moments, the CRT LED will turn off and the LCD will show all pixels. I can also reliably cause this to happen by touching the CRT clock signal line with my finger.
While this seems promising as it may point to possibly a short or a bad connection, I can't help but wonder if this is a red herring and that the problem is actually more fundamental, like a broken trace between RAM, ROM, CPU, and the display controller possibly... or one of these components being faulty.
I'm just not sure though. If anyone has some insight or more expert advice, I'm all ears. What would YOU do?
In the meantime, I'll start going through and verifying connections, and maybe replace that PRAM battery just in case. Thankfully the schematics and lots of other good info is in the maintenance manual: http://www.minuszerodegrees.net/manuals/Toshiba/Other/Toshiba T1100 PLUS - Maintenance Manual.pdf
The machine is new to me, and I received it in a non-booting state (i.e. despite using a good battery and the correct adapter, it does not boot). When turning the power on, the Power LED and CRT LED light (indicating good power, but the LCD is disengaged - which I understand to be abnormal at startup), but the machine does not appear to POST: no image appears via LCD or composite, no beep. The keystroke to select LCD does not do anything. I confirmed all switch, DIP, and jumper settings are appropriate (however, there are some jumpers that are not described in the docs).
I then recapped the power supply board, logic board, and display board, cleaned the boards and all connectors, but no change in symptoms. I have confirmed that the power supply board is providing the proper voltages. I did a quick visual inspection of the boards, and confirmed any suspicious traces - but I could do a more thorough inspection.
The PRAM battery has been removed and not replaced (god I hope this isn't the issue... or maybe I hope it is?).
However, as what sometimes happens while handling parts, I can cause a change in behaviour. I first noticed that - sometimes - while moving the display cable or the LED assembly while the computer was powered on, the CRT LED would turn off and the LCD would show all pixels... but nothing else would happen, it would just stay like that. This same thing now happens fairly randomly when powering the machine on - after a few moments, the CRT LED will turn off and the LCD will show all pixels. I can also reliably cause this to happen by touching the CRT clock signal line with my finger.
While this seems promising as it may point to possibly a short or a bad connection, I can't help but wonder if this is a red herring and that the problem is actually more fundamental, like a broken trace between RAM, ROM, CPU, and the display controller possibly... or one of these components being faulty.
I'm just not sure though. If anyone has some insight or more expert advice, I'm all ears. What would YOU do?
In the meantime, I'll start going through and verifying connections, and maybe replace that PRAM battery just in case. Thankfully the schematics and lots of other good info is in the maintenance manual: http://www.minuszerodegrees.net/manuals/Toshiba/Other/Toshiba T1100 PLUS - Maintenance Manual.pdf
