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Toshiba T5200 mods and upgrades

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Reply 80 of 534, by IanB

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Vipersan wrote:

I have yet to start the SIMM/RAM mod ..but at some point I am going to have to bite the bullet and pull the mainboard out to do the 486 CPU mods ..
Been back through you thread ..and not seeing any real detail for this..unless I missed it.
Did I miss something ..or perhaps you haven't posted the details yet.

I haven't posted details yet but will do shortly.

Reply 81 of 534, by IanB

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kultakala wrote:

Edit: My second T5200 does nothing anymore... after replacing the floppy drive it starts, power led lits but nothing else... Hmmm...

Do you see any flash of activity on the right hand leds when you startup? (they normally briefly flash just after power up)

A few things to check:
Make sure all the connections under the floppy drive cage have been reconnected.
If you are testing with the cover removed, make sure the screen blanking switch fitted next to the leds above the floppy drive is pushed in (also check the connections to it)
If you have a working CMOS battery fitted, disconnect it for 5 mins (with the power off)

Reply 82 of 534, by Rolandradio

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Nice upgrade you made IanB.

Good explaned about the 4 CPU's

The nicest is that you but XTIDE in the MainBIOS.
Is there a solution for this case:
Industrial MOBO VMEbus Xycom 686
It's a 386sx-25 with 1 bios D27C4001, this mainboard has no ISA bus.
Is it possible to put XTIDE in this BIOS ?
See file: Xvme.txt (change extention .bin)

With the HEX editor I see there is some space free.

Other question:
if a mainboard has a 27C512 eprom can you also put a 27C010 ?

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Reply 83 of 534, by kultakala

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IanB wrote:

Do you see any flash of activity on the right hand leds when you startup? (they normally briefly flash just after power up)

Yes, all 3 leds light up for half a second and again after 2 seconds.
But there is no harddisk or floppy activity and nothing on the display.

IanB wrote:

Make sure all the connections under the floppy drive cage have been reconnected.
If you are testing with the cover removed, make sure the screen blanking switch fitted next to the leds above the floppy drive is pushed in (also check the connections to it)
If you have a working CMOS battery fitted, disconnect it for 5 mins (with the power off)

I dis- and reassembled it for about 20 times by now... it always worked.
When case is open i place a tape over the switch 😀
All connectors are good and with the now closed case its still not working.
But i will try to disconnect the cmos battery.

Btw, i was able to get an original new cmos battery from Tadiran, made in Israel.
They still produce the batteries, they are often used in military equipment.

Reply 84 of 534, by IanB

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Rolandradio wrote:
Is there a solution for this case: Industrial MOBO VMEbus Xycom 686 It's a 386sx-25 with 1 bios D27C4001, this mainboard has no […]
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Is there a solution for this case:
Industrial MOBO VMEbus Xycom 686
It's a 386sx-25 with 1 bios D27C4001, this mainboard has no ISA bus.
Is it possible to put XTIDE in this BIOS ?

The main 64K BIOS at F000:0000 doesn't have any space left but it looks like the EPROM occupies the whole of the memory map from C000:0000 to F000:FFFF and there are lots of other blank spaces where XTIDE would fit. However those areas may not be visible in the memory map and may be overlaid by RAM or other things which is how it is on the T5200 (The first 64K of the 128K T5200 BIOS EPROM is blank but it doesn't show up in the memory map so is of no use)
I've put XTIDE in a couple of positions for you to try but they may not work because of this:

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Rolandradio wrote:

Other question:
if a mainboard has a 27C512 eprom can you also put a 27C010 ?

A 27C512 is 28 pin and a 27C010 is 32 pin so how many pins are there on the socket?

Reply 85 of 534, by Rolandradio

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Thanx, I wil try.
But XTIDE has to be fit in the first 64kb location, this location of RAM is never overwritting once the computer has booted, right ?

And here is another BIOS, maybe XTIDE can fit in this BIOS.
File : ChiconyNB5625.bin

When the Eprom has the same pin count, can I put a 27C512 instead of 27C256 or is the adressing location than wrong ?

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Reply 86 of 534, by matze79

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php3nS0fS.jpg

https://www.retrokits.de - blog, retro projects, hdd clicker, diy soundcards etc
https://www.retroianer.de - german retro computer board

Reply 87 of 534, by Vipersan

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For the record Ian..
There is nothing easy about this.
Once upon a time I would have had no problems with this process ..but MS has reduced my dexterity/motor skills ..and seriously affected by eyesight.
Took me over 3 hours just to do one side of 36 wires..
but although the soldering is not the greatest..at least the meter/buzzer reports no adjacent shorts.
rgds
VS

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Reply 88 of 534, by Vipersan

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The story so far ..
got two ribbons attached to the simm..
checked for adjacent pin shorts ..
The 100uf caps fitted ..so I guess it's time to start connecting the simm to the pcb .
I figure you can't see enough photos so I'm adding mine ..
both for reference and so that Ian can keep an eye on my progress.
rgds
VS

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Reply 89 of 534, by Vipersan

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This is really hurting my eyes ..so ..time to take a break.
Using coloured ribbon has pros and cons.
Pro ..it does make wire identification easier ..though 10 is black not red (+5) ..a little confusing.
Con ..the different coloured sleeving tends to heat and contact at different rates ..making tinning the wire ends ..tricky.
Ian mate ..you must have the patience of a saint.
😁
rgds
VS

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Reply 91 of 534, by Vipersan

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I rather think I have misinterpreted A and B ..
I had assumed on of the 40 pin slots as A (IS16)and another as B (IS15) ..
re-reading it looks like Ian has designated half simms as A and B ..
So all work stops until I hear from Ian.
I rather think Id had to start over if my hunch is correct.
DOH!!!

Reply 92 of 534, by IanB

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Vipersan wrote:

I rather think I have misinterpreted A and B ..
I had assumed on of the 40 pin slots as A (IS16)and another as B (IS15) ..
re-reading it looks like Ian has designated half simms as A and B ..

Each pair of SIMM slots has a single label on the component side so there are 6 slots but only 3 labels (IS17, IS16 & IS15 - ignoring the short 30 pin slot). The middle pair is IS16 and one slot I have referenced as "A" and the other as "B" although they are not labelled.
You seem to have labelled the correct rows of pins on the underside in your photo so thing look OK for that.

However, comparing the instructions with my actual circuit I may have swapped a few of the last connections I made between "A" and "B" as they don't match so I'm just checking through things now. (It's likely the row and column address strobes)

Reply 93 of 534, by Vipersan

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Thanks for the reply Ian..
Will start again tomorrow ..
as I keep saying ..this really gives me eye strain.
Just to confirm so I have it clear in my head ..
I've attached paper labels topside on what I now think is correct ..
rgds
VS

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Reply 94 of 534, by IanB

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Vipersan wrote:

I've attached paper labels topside on what I now think is correct ..

No that is not correct, as I said above, your underside labels were correct. "A" is the one straight row of 40 pins and "B" is the other straight row of 40 pins.

I'll post an update with some more explicit labelling once I've checked the connections.

Reply 96 of 534, by IanB

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Vipersan wrote:

So ..looks like I had it right first time ..and doubt crept in..
I'll wait for you more specfic labelling.

I hope this makes things clearer:

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I checked the pinouts on the instruction post and the RAS lines had their "A" and "B" swapped compared to the way it's wired up although it actually wouldn't make any difference as the "A" and "B" of those lines are connected together anyway.
I've edited the original pinout post to correct this and make it match the photos.
To change it you will need to move wires 33 & 34 from "A" to "B" as follows:
Wire 33 to Pin 20B (Row Address Strobe 3)
Wire 34 to Pin 17B (Row Address Strobe 2)

I also changed the other two but you haven't wired those up yet:
Wire 44 to Pin 17A (Row Address Strobe 0)
Wire 45 to Pin 20A (Row Address Strobe 1)

I have edited the original post so it shows the above corrected pin numbers and it also shows a copy of the above photo with labelling.
The rest of your wiring looks OK so far.

Reply 97 of 534, by Vipersan

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Well fwiw I completed the wiring ..
This mod is not for the faint hearted imo..
😀
Anyhoo ..tonight I shall try buzzing it out before applying power to test ..
..which should be relatively straightforward ..due to the simm mounting (all done from topside)
Thanks again for your help Ian
rgds
VS

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Reply 98 of 534, by Vipersan

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Another question for you Ian ..
Your list says ..If the pin is not designated with A or B ..then either row of 40 pins can be used ..
My question relates to Wire 47 to pin 19 read/write which does not have an A or B designation ..
I took wire 47 to pin 19 of the 40 pin slot closest to the 2 proprietory sims ...which I assume is correct ?
but on mine the two 40 pin slots (pin 19s) are not linked ...so I assume designation A ..
correct or not ?
I have pin checked all the others which buzz out ok ..
Is this an error on my memory board and should both pin 19s be linked ?
or is this an oversight in the pin list ?
rgds
VS

Reply 99 of 534, by Vipersan

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Working on the assumption my hunch was correct ..I popped the pcb in ..
..and entered the bios ..
see picture for result
rgds
VS

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