Sometimes you get a screw which kinda circles the thread lower down and you need to pull on it by best means necessary (tweezers, needle nose pliers, pickle picker etc) while turning to engage it in the upper thread and get it to turn all the way out.... however, there's other cases where brass inserts just pull out and spin.. much the same technique though you often have to pull it quite tight and keep the tension on all the way out.... and try to catch it/locate it as it falls off the back so it doesn't end up stuck somewhere or forgotten and shorting something.

I know what your saying and I did apply a little upward pressure on the screen assembly to keep some tension on the screw as I was unscrewing it, but it shows no signs of coming out completely. After I posted my note, it dawned on me(I had forgotten this) that I must have had this screen off back in the day. When I worked from home in the late 80s I had a nice 14" monitor I would use with it, so it's possible the last time I put the screen back on, I screwed (no pun intended) something up. But it's still rather surprising that it just it won't come out. I can tighten it back down just fine. I can't go much further with the unit until I can get the screen off. 🙁

Ah if it tightens back up again maybe it's a screw in standoff type thing that has unscrewed at the bottom and won't unscrew in the middle 🙁

Now I've gone and done it! The head of the screw is hopefully stripped and looks like my only option is to drill off the head. The good news is this screw does not affect the operation of the computer or the screen. It just provides a bit more structural strength to the plug and jack assembly of the screen. I have no idea what kind of assembly the screw is attached to, but it really got tight - while I was stripping the head. Once I get the screen off and can take the top half of the computer off, I should be able to get the screw from whatever it's attached to and fix it. It would make sense that it went into a plastic standoff with an insert in it that may have broken off, but that doesn't explain why it tightens back down. Of crap! 🙁

Well, I didn't have to drill off the head. I just twisted it off. That screw was hopelessly bound in the fitting. Now I'll have to drill it out and repair the hole.

download/file.php?mode=view&id=130611

Here are some pictures of the inside of my T5200. It's very clean and more dust free than I would have thought. But then it never was used in dusty environment. Either I never knew it, or had forgotten that this had a hard drive in it. So I'm curious why it won't boot. Surely it was able to boot off the HD? The reason I had to open it was to get to the battery. I keep getting the battery warning when it starts up. It needs to be replaced. Once I replace the battery, I'll reassemble and check out the BIOS more closely for an option to boot from the HD. I see now that the setup screen shows a HD.

Ah you fibber, that's not a genuine vintage computer, somebody made that last week. 🤣

Just kidding, it is real clean.

Hey redjr (I tried to PM you but the forum won't let me 🙁 )

I can't help you with a physical disk, but as you may know, those floppy drives aren't the most reliable. I bit the bullet and replaced mine with a gotek floppy emulator, as my floppy drive was DOA. There's a trick to this though, you need to hack the ribbon cable as it's non standard (but I think you can buy them on ebay now?).

There's pics and info in my signature too.

The hdd issue might be due to the cmos-battery (causing bios alzheimer) but should probably only be a matter of setting the correct type in order for it to boot up. I did not fall for the Gotek thing personally (thats waaaay to modern for me 😉) and so i basically wired up this special cable (its documented earlier in this thread) and stuffed a regular 1.44 floppy drive inside. Works perfectly fine also.

my03 wrote on 2022-02-17, 13:09:

The hdd issue might be due to the cmos-battery (causing bios alzheimer) but should probably only be a matter of setting the correct type in order for it to boot up. I did not fall for the Gotek thing personally (thats waaaay to modern for me 😉) and so i basically wired up this special cable (its documented earlier in this thread) and stuffed a regular 1.44 floppy drive inside. Works perfectly fine also.

For the moment, I'm going to assume the floppy is working cause when I do try and boot the the little LED indicator on the left flickers a bit indicating it's trying to read from it. I'll know more when I get a bootable disk. A friend of mind in NY is snail mailing me a generic MS-DOS disk. If it boots consistently, I can rule out the drive. Then I can see what's on the HD. Years ago when my son and I were building computers we had tons of parts, drives, etc. But I never kept a 3.5" drives. Still building and upgrading computers occasionally, but also trying to thin out my shop and basement. It's too full!

BTW, does the floppy controller header on the motherboard provide standard pinouts? I know the external floppy connector on the back is not standard. Why do manufactures do this? Became aware of the Gotek device last Fall when I was restoring my SOL-20, but never popped for one. May rethink that with the T5200 and hjow easy (or difficult) it would be to get it working with the T5200.

16ShadesOfOrange wrote on 2022-02-17, 04:31:

Hey redjr (I tried to PM you but the forum won't let me :( ) […]
Show full quote

Hey redjr (I tried to PM you but the forum won't let me 🙁 )

I can't help you with a physical disk, but as you may know, those floppy drives aren't the most reliable. I bit the bullet and replaced mine with a gotek floppy emulator, as my floppy drive was DOA. There's a trick to this though, you need to hack the ribbon cable as it's non standard (but I think you can buy them on ebay now?).

Edit: I see now that 34-pin connector is not a floppy controller, but the header for the display.

There's pics and info in my signature too.

Good stuff there. Can you easily replace the Conner HD with a more current drive in the T5200, or are there limitations due to the standard Toshiba BIOS? I guess the BIOS has already been hacked from my snooping around in this thread. More to investigate.

@16shadesoforange What model of the Gotek emulator did you use?

Edit: Is there max size limitation to the CF card that the T5200 will support?

redjr wrote on 2022-02-17, 14:03:

For the moment, I'm going to assume the floppy is working cause when I do try and boot the the little LED indicator on the left flickers a bit indicating it's trying to read from it. I'll know more when I get a bootable disk. A friend of mind in NY is snail mailing me a generic MS-DOS disk. If it boots consistently, I can rule out the drive. Then I can see what's on the HD. Years ago when my son and I were building computers we had tons of parts, drives, etc. But I never kept a 3.5" drives. Still building and upgrading computers occasionally, but also trying to thin out my shop and basement. It's too full!

BTW, does the floppy controller header on the motherboard provide standard pinouts? I know the external floppy connector on the back is not standard. Why do manufactures do this? Became aware of the Gotek device last Fall when I was restoring my SOL-20, but never popped for one. May rethink that with the T5200 and hjow easy (or difficult) it would be to get it working with the T5200.

I don't think it is completely standard tbh. I followed the guide here when i build my own flat-cable (Re: Toshiba T5200 mods and upgrades) and it worked immediately. But i do recall that also my original drive flashed like you described it but did not read (i was a bit lazy at this time and figured "why not put a direct drive unit in there" instead of opening the original one up and perhaps change the belt, etc).

This machine afaik more or less only supports a few number of drives, all Connor ones (i believe between 40 - 200mb?). I burned Ians modified roms (with xt-ide support embedded) in mine and connected a ide/CF adapter (4GB). Works perfect.

I like the CF card adapter solution too. Solid state is faster, larger and more reliable for sure. I've even got one of those miniature IBM drive that was in the CF card format. It stored 340MB IIRC. But if your data is stored, or would otherwise like the ability to read 3.5" diskettes then you'll need a drive. I'm searching on ebay to see what I can find in the way of 40-pin adapter to CD card interface. If my original 3.5 drive works, then I'll just leave it in, unless I go the Gotek route instead. I've worked with ribbon cable and drive connectors years ago - as in 40+ yrs ago!), but would rather not do all the tedious work involved in customizing a cable if I don't have to.

@redjr

BIOS is limited to (3 that I know of) Conner drives. BIOS hack required if you wanna swap in a standard IDE, or you can use things like ConventionalMemories' CF expansion card, or even a SCSI card/network card with boot ROM (using XTIDE). Info on my github in my sig.

Regarding the floppy - from memory, my floppy LED was doing the right things but it failed to read/write anything. I don't know if that's a common symptom of these failed drives though? I installed the most basic Gotek (I think this one: http://www.gotekemulator.com/P_view.asp?pid=68). You need to use the software to partition the USB into 1x 1.44MB partition. If you spend more, you can get a Gotek that lets you use heaps of "disks" on one USB (they have buttons and LED readouts for selecting the disk number).

If you have a Win9x machine you might be able to format your T5200's HDD (and include system files) to make the HDD bootable:

http://starman.vertcomp.com/DOS/bd98/Format.gif

@16shades,

Thanks for the additional info and links. Once I get it bootable I'll explore my options for modernizing it. Seems I have a few choices. I certainly don't need it for anything, but I would like a working machine should I decide to sell it.

If this post shows up twice, my apologizes.....

I'm prepping the new 3.6V battery to install, and have a question. Is the 330 Ohm resistor in line with the neg. lead required?

Update....

I replaced the CMOS battery , connected everything back and was greeted with the SETUP screen. Reset everything to default, rebooted (F10), and DOS came to life on the C: drive. Not sure why it didn't boot to C: before. Maybe just the battery That's the good news. 😀 I tried drive A: and kept getting a read error, so it looks like that one is bad. I've got a NOS replacement coming.

redjr wrote on 2022-02-16, 22:43:

I know what your saying and I did apply a little upward pressure on the screen assembly to keep some tension on the screw as I was unscrewing it, but it shows no signs of coming out completely. After I posted my note, it dawned on me(I had forgotten this) that I must have had this screen off back in the day. When I worked from home in the late 80s I had a nice 14" monitor I would use with it, so it's possible the last time I put the screen back on, I screwed (no pun intended) something up. But it's still rather surprising that it just it won't come out. I can tighten it back down just fine. I can't go much further with the unit until I can get the screen off. 🙁

Well, its might be to late now perhaps, but (for future reference) there are two screws involved (to my knowledge) in separating the screen from the chassie. First one is visible on top and the second one "hides" behind the small plastic lid just above (with a small "cranny" that a small flathead screwdriver can lift up). With those two loosened (they will not come off completely) and those two levers on the front of the screen in their inner/lower position, the whole assembly will just come off the chassie 😀

The "Matrix" T5200 - trials and tribulations

A while back i bought this unit as a spare

(also mentioned beginning from here: Toshiba T5200 mods and upgrades)

and out of curiousity, i tried a few things to see what the culprit might be with it. As i have a fully operational T5200, went out and tried the following:

• Swapped the screen assembly (did not change anything)

• Swapped out the graphics card (did not change anything)

• Swapped out the memory expansion board (did not change anything)

• Swapped out the PSU (you guessed it - did not change anything)

• Replaced the BIOS + VGA rom (nope, no change)

• Disconnected HDD (and FDD) and tried an XT-ide card (no change)

Lastly i sent the unit off to someone more skilled and they basically re-soldered every chip/cap/everything in case of bad joints (no change)

But then i read someone mention that they had seen a similar behaviour caused by a short in the RTC chip (MC146818A) and pursuing that lead i did not manage to source this exact model of RTC, but (hopefully) a compatible one in the form of an Hitachi HD146818AP (info taken from here: https://ardent-tool.com/misc/MC146818.html). I also got the advice (awaiting this chip to arrive) to test basically cutting the ground lead(s) of the current RTC to see if it makes a difference.