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Toshiba T5200 mods and upgrades

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Reply 300 of 343, by Vipersan

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Hi ..
I just picked up the internal 5v or was it the 12v ..? from the hard drive connector. dont remember exactly as it was a while ago ..
but suffice to say it was easy and draws a low current so not a heavy load.
Same goes for the vga passthrough..
rgds
VS

Reply 302 of 343, by my03

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Hi all,

sorry about hijacking this thread but i recently got my hands on a T5200/100 in nice condition - besides the floppy - and i wonder WHAT usually the issue is with these floppy drives (usually)? capacitor issues? regular wear?

Reply 303 of 343, by yourepicfailure

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Pretty much any number of unknown things as you said. Oxidation could've caused a bad solder joint, bad caps... Ones especially in units not stored right need a good head cleaning and a stepper motor fixup and lubrication.
But sometimes the voltages going into it are a little off like from a failing PSU. That was the case with my T3100SX, which I think uses a similar floppy drive as the T5200. It would throw off constant read errors with disks that read perfectly in other systems. Turns out my T3100SX's power board was going out *again* and had badly sagging voltages. Once the board was recapped for a second time, the drive ran well.

Maybe this could be a predictor, but these Citizen drives were made either in Japan or China. I happen to have two Japanese drives, and *knock on wood* they still work.

Reply 304 of 343, by my03

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So, i built the cable (taking extra care to get everything right). The machine boots up but when i try to format the floppy ( ALPS DF354 1.44mb unit) i get a "device not ready mesage". The floppy does come alive and reacts but will not go all the way, so i guess there is something with the cable. Tried two other drives (different manufacturers) with the exact same results. What pin would be the prime suspect?

When reading Ians initial post, i can see this:

"wire 8 >> pin 5 !READY >> GND (Ready is not a signal present on IBM type floppies but needs to be grounded to work)

Warning: Some drives (e.g. more recent Mitsumi drives) don't have all the GND pins fitted on the 34 way socket. This means that the !READY signal might not make contact with GND if pin 5 is missing and the drive may not work. Pin 5 is present on the Mitsumi drives which is why that one is used but if other manufacturers did the same thing and didn't have pin 5 then you might have to move that wire to another pin or connect it directly to GND.
Also as there are fewer GND pins, there may be insufficient GND return for the +5V supply"

right or wrong - would this imply that it would be possible to connect wire 8 to one of the other ground pins on the floppy-side IDC?'

While perpahs not relevant for the Toshibas, i found this other translation table between 26-34 that looks like the following and i wonder if it would not be possible to connect (26-pin) #8 to the (34-pin) #34 for "drive ready/disk changed"?


26-pin Conne 34-pin Signal
cable cted? interface Name Description
1 No VCC +5V
2 Yes 8 /INDEX Index
3 No VCC +5V
4 Yes 10 /DS0 Drive Select 0
5 No VCC +5V
6 Yes 2 /DSKCHG Disk Change
7 Yes 12 /DS1 Drive Select 1
8 Yes 34 /RDY Drive Ready/Disk Changed
9 No Not Connected
10 Yes 16 /MTRON Motor Enable
11 No Not Connected
12 Yes 18 /DIR Direction
13 Yes 13 GND Ground
14 Yes 20 /STEP Step
15 Yes 15 GND Ground
16 Yes 22 /WDATA Write Data
17 Yes 17 GND Ground
18 Yes 24 /WGATE Write Gate/Floppy Write Enable
19 Yes 19 GND Ground
20 Yes 26 /TRK0 Track 0
21 Yes 21 GND Ground
22 Yes 28 /WPT Write Protect
23 Yes 23 GND Ground
24 Yes 30 /RDATA Read Data
25 Yes 25,27,29,31,33 GND Ground
26 Yes 32 /SIDE1 Head Select

Last edited by my03 on 2019-12-04, 12:26. Edited 5 times in total.

Reply 305 of 343, by my03

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yourepicfailure wrote:

Pretty much any number of unknown things as you said. Oxidation could've caused a bad solder joint, bad caps... Ones especially in units not stored right need a good head cleaning and a stepper motor fixup and lubrication.
But sometimes the voltages going into it are a little off like from a failing PSU. That was the case with my T3100SX, which I think uses a similar floppy drive as the T5200. It would throw off constant read errors with disks that read perfectly in other systems. Turns out my T3100SX's power board was going out *again* and had badly sagging voltages. Once the board was recapped for a second time, the drive ran well.

Maybe this could be a predictor, but these Citizen drives were made either in Japan or China. I happen to have two Japanese drives, and *knock on wood* they still work.

Thx for some nice insights. I need to check the origin of my unit as well (and try to measure the voltages) 😀

Reply 306 of 343, by yourepicfailure

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On another forum, I found a post by someone who pulled something similar with a T3100SX which uses a similar 26-pin interface.
http://www.vcfed.org/forum/showthread.php?561 … n-floppy-drives

It appears a similar process with old synthesiszers. This should provide some helpful links.

However TL;DR to answer your question,

Not all drives provide a signal when they are ready and not all controllers make use of it. This signal is active low, so if you […]
Show full quote

Not all drives provide a signal when they are ready and not all controllers make use of it. This signal
is active low, so if your controller needs it and if the drive does not provide it, then you can short the
signal with the adjacent GND pin. It is said that this may cause a few retries, whereas it works
perfectly fine for others. But if your drive provides a ready signal, then use it. Note: The Amstrad
PCW models require this signal. Further, they require its absence for recognizing that there is no
disk in the drive. An artificial RDY signal must be provided if the drive does not offer one, which
modern 3.5" drives don’t, although other ones do.

from http://www.hermannseib.com/documents/floppy.pdf

also in that post. The individual who quoted that article did state this procedure worked. So by all means, go for it.
I wish I could provide more insight, but I haven't had to replace my drive yet.

Reply 307 of 343, by my03

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Thx again 😀 I will read through that document.

On the flip-side of my trials with the floppy and cable, i somehow (don't know why) managed to come to a situation where the machine now halts with a "Parity error 2" instead of booting into ms-dos. When entering the setup, i do notice that my expanded ram is no longer visible on that screen. I tried to remove all of the (6) sticks from the memory expansion board and start the machine without them but still got the same error. Reinserting them again once more gave this error.

I don't know if anything might have come loose (will ensure that this is not the case) but i fear that i might have fried something. Since the error shows without expansion ram in, i fear that the base-memory might have been affected. Have anyone gotten this error (and managed to recover from it preferrably)?

Reply 308 of 343, by henryVK

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Any of y'all Toshiba T-series cats know what this screen garble might be indicative of?

Pic is of a machine that I found on local ads. The seller says he got it off someone else and it appears that the previous owner has messed with the BIOS.

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Reply 309 of 343, by yourepicfailure

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my03

Yes, likely a memory chip has gone. Yes and no expected on old machines. Luckily, everything else works fine so chances you didn't fry something are high. I am still higly recommending you look into that PSU. Whether ram went out or a PSU is about to go, you'll need to dismantle the unit to investigate. Luckily there sre ways to connect a regular PC psu in and operate it from there if the original PSU is failing.

HenryVK

Three things possible:
1. The bios eprom (which has the VGA Bios) could have corrupted.
2. Somewhere between the VGA controller, the TTL converter, and the panel has a bad joint.
3. I'm going to repeat PSU like a broken record, I have pics of my T3100SX spurting out garbage like this when I was testing a PSU repair. Actually, just like this with random, changing squares and only partially discernable content. Needless to to say, the psu still wasn't fixed and the panel wasn't getting enough power.

Reply 310 of 343, by henryVK

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@yourepicfailure

Thanks for your answer!

I'm only 50% sure I could fix either of those and I don't have an eeprom programmer. Maybe somebody else wants this machine? It's in Germany and the asking price is only 25€.

Reply 312 of 343, by henryVK

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I'd give it to you but it's not mine, I just saw it in this ad:

https://www.ebay-kleinanzeigen.de/s-anzeige/l … 194219-278-1065

Maybe you can get this person to ship to Sweden? Shipping would be around 16€.

Reply 313 of 343, by my03

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Thx henryVK, i contacted him and have to keep my fingers crossed that he can ship 😀

yourepicFailure, you are most probably right. For me, question is "which" chip (i guess) would be the culprit. As far as i can tell, there are 8 256KB dram chips, but would then those 74F04N be related to the parity bit? When i google 74F04N i get information that these are hex inverters (which i assume controls what/when to read from which simm?)

79482217_10156923394128450_7105719238827966464_o.jpg?_nc_cat=107&_nc_ohc=n1rWAaEF4doAQmZb-kezG4yeUSqDJGvUZCVBY4MHr8b7p2deZobrm9N4w&_nc_ht=scontent-ams4-1.xx&oh=ab522d83b845e1508f1c3381ec8453d3&oe=5E417011

Reply 314 of 343, by yourepicfailure

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The hex inverters are there for the memory addressing as you said.

Want my input? My first guess would be the one that stands out from the rest. All others have code 8452j06 while that one has 8452j00. What I would recommend is each one you desolder, resolder a socket so you don't have to solder to desolder to solder again.

As for how a dying PSU could cause the display to throw off garbage, the panel runs off of 12v and 5v. 12v for the inverter, and it needs a whole lot of it. Judging by how the display is throwing out garbage, it is receiving enough 12v for operation. However, the panel does not combine 5v input supply to drive all components. Instead, each of the 5v supply pins goes to a different portion of the panel drive logic. If the PSU is sagging on one of those 5v rails, a component will not get enough power for proper function hence the partial garbage.

If only I still lived in Germany I would've snatched that unit up.
Since I can't send you a message, HenryVK or my03 if you are willing to do this I am in turn willing to pay for full cost of the unit and cost to ship and handle the unit to me.

Reply 315 of 343, by my03

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Got it. I did not even catch that difference. I searched for that particular string but found nothing (would they all be the "same" type of dram?).

But i have some good (and weird) news also. This morning i tried once more to start it up and saw it start to count the memory (not to 1024 this time, but all the way up to 2048). The second iteration actually showed all of the 8MB expanded (also in bios this was shown) and the machine, for now at least, looks completely normal again. This is quite odd but nice of course. I guess there are trolls inside this machine.

(oh, and the floppy cable works fine also, coupled to an Alps drive 😀)

Thx

Reply 316 of 343, by OldCat

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Ha, ha, I was actually pondering the same ad, but decided my kung-fu it too weak to deal with that. Would love to get my hands on either T3200 and T5200, but unfortunately these are few and far between.

In Polish local ads I have found T3200, but its screen doesn't show anything, it just gets lit up (seller's words). Once again, seems like something broken that I would not be capable of repairing.

I still have a broken T3200SX model that I bought cheaply, hoping I could restore it. Sadly, it turned out to be broken PSU and friendly electrician said he couldn't repair it. So it sits there waiting for my primary T3200SX to fail, at which point I will harvest its organs.

Reply 317 of 343, by jaZz_KCS

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My T3200SX is still fully working with original screen and FDD (although I replaced the BIOS chip (thank you again, Vipersan!) and made a FDD adapter cable to be able to use generic drives once the original one bites the dust). But I am fearing the day the PSU will cease, and a simple recap wouldn't be enough to fix. In terms of specs it doesn't seem to weird, the usual 12V, 5V, etc... but according to the manual and documents around (which thankfully actually states the PSU details as well) it is a very weird pin-out...

Reply 318 of 343, by yourepicfailure

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Pretty much the only other thing on these PSUs that have a considerable chance of failure than the caps are the regulating mosfets. That and the traces if well, you mess up.
The full switching PSUs on machines other than the T3100SX are fairly resilient if you keep them maintained. Much easier to swap the mosfets out if they happen to fail unlike the T3100SX which has them encased in ceramic paste sandwiched between two aluminum heatspreaders soldered to the board.

I am making a request here. I am looking to see if someone is willing to disassemble the plasma panel assembly (or LCD if you have that version) of a T3200SX and T5200 for pictures. Preferably individuals who have faulty panels (so as not to chance ruining a working display).
If there are individuals willing to take this on, I'll post further information on the photos I'm requesting. The reason I'm requesting detail is I'm studying the panel interface to find out a method of using the TTL interface to drive a modern replacement panel on these units to avoid sacrificing the VGA port or performing risky board soldering.
I sadly have neither machine (only T3100SX), but if my belief is correct, these machines should use a similar display interface (T3100SX, T3200SX, T5200) regardless of pin configuration. I just need the pictures to verify this.

Reply 319 of 343, by jaZz_KCS

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Well, considering you pretty much have to disassemble the complete display unit (up to the point of screwing out the driver board from the diplay chassis) every time you want to completely open up the T3200SX, as you need to guide the cables through the hole in the middle) every owner of one should be familiar with this procedure.

If no helpful pictures arise until then I can promise to make some detailed photos next time I have it opened up for maintenance, which should be end of this year at the latest.