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Display and comms problem with Sanyo 16LT

Christoffer

Experienced Member
Joined
Oct 15, 2014
Messages
299
Location
Denmark
Hey! So i recently found a Sanyo 16LT at a flea market. Since it looked physically in good condition, i bought it.
Upon opening, it also looked fine, no leaking of batteries or corrosion etc. It came with an original boot disk too.

It sounded like it was booting just fine, the battery even charged! - though the LCD remained off.
After trying some things, i removed the LCD, to see if it had any obvious faults or loose connectors - nothing, though it remained dead.
It does have a display out, dsub9 connector labeled "RGB" - i suspect its CGA, but i can't find any documentation on it.
Besides the screen, it seems to be booting fine from the boot disk, it beeps, floppy drive whirr's, and after a while, it seems like it takes commands.
writing DIR (it's a DOS machine) the floppy spins up again, as one should expect.

Does anyone know this system, the display or the error I'm having?
 
Also: Since there isn't that much info on this machine, I'm gonna add some images of the computer and boards.
Some Interesting things I've noticed, is that besides the 8088 (at top, with the Eprom, the other 40-pin dip package (with the other Eprom)
is an Intel 8049 microcontroller. Probably acting as peripheral interface. The 4-pole dip switch on the side in the lower left corner, i believe, is
for the CGA RGB output, each combi specified a unique display mode, though again, info on this is sparse.

The lower left Eprom (2764) may be for the 8049, but that already has 2Kbyte of rom, not sure how much it would need to
run the LCD and keyboard and a few other things. actually, i think the LCD has a seperate controller.
I haven't traced it yet, but it may be that the Eprom holds the display mode info, and that the dip switch is accessing that
via the address bus directly, like one would do it with a PROM in the earlier days, but i haven't traced it on the board yet.

IMG_0285.jpg
IMG_0286.jpg
 
I do not know about your particular make/model of laptop, but in case it somehow helps:
The symptom is seen is some Toshiba laptop models. The cause is detailed [here].
 
That does indeed seem interesting! The battery does hold some charge, though it's a bit too low to be comforting. I'll try another power supply when i get back to the bench!
As for the backlight: I don't think that's the issue, since the display has none :) - also: It affects the RGB out as well.
I did make a post here with some info about the system and some images of the boards, but it seems to have been lost in spam filters.

-Thanks--
Christoffer
 
That does indeed seem interesting! The battery does hold some charge, though it's a bit too low to be comforting. I'll try another power supply when i get back to the bench!
I saw the symptom in a Toshiba model different to the ones quoted in the alert letter that I pointed to.
Remove the battery; display appears. Put the battery back in; display disappears.
Affected the VGA connector as well (yes, key sequence to activate the connector was used).
Details [here].
 
Well i haven't really bothered to charge the battery, so that could be it. The psu doesn't seem to operate at all without battery installed, I'll have to fit a 5V supply directly at the battery terminals. After trying to charge the battery fully. Did find some failed caps on the PSU board, but it didn't seem to fix the trouble, Thanks again.

--Christoffer
 
Hey! So i recently found a Sanyo 16LT at a flea market. Since it looked physically in good condition, i bought it.
Upon opening, it also looked fine, no leaking of batteries or corrosion etc. It came with an original boot disk too.

It sounded like it was booting just fine, the battery even charged! - though the LCD remained off.
After trying some things, i removed the LCD, to see if it had any obvious faults or loose connectors - nothing, though it remained dead.
It does have a display out, dsub9 connector labeled "RGB" - i suspect its CGA, but i can't find any documentation on it.
Besides the screen, it seems to be booting fine from the boot disk, it beeps, floppy drive whirr's, and after a while, it seems like it takes commands.
writing DIR (it's a DOS machine) the floppy spins up again, as one should expect.

Does anyone know this system, the display or the error I'm having?
if you still have this computer and battery , would you consider to sell ? thanks , mine did work good but i took the battery out for storage an its gone missing .. this computer wont run without one even with the power adapter plugged in ...thanks in advance
 
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