A couple of retros I'm working on.

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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-08 @ 20:56

Great info as usual JZ ..
I am hoping I can fix this slim floppy ..but good to know that there are alternatives ..
Certainly not built for easy access this one ..
A full strip down needed just to expose the hard drive ..
I'd like to use the original here too if possible ..
125mb is certainly large enough for win3.1
.much like the 5200 and conor..
I do like to keep things authetic if possible..
Same goes for my Commodore collection.
Not much chance of ever finding trackball mouse but you never know..
;)
rgds
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-08 @ 21:41

The general rule of thumb with this era of laptops is to take good care of the (mostly unique in length and uniquely bent) floppy/ide connectors. You are most of the times able to substitute the drives, but the connectors to the planar are a different story...

There are still various 2/3rds drives available on ebay and the like, if everything goes awry regarding to the floppy. In regards to the IDE, if it still works...splendid. If not, to keep it as original as possible, you would need another 500mb-2gb drive :P
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-09 @ 20:01

If this floppy ever works again..it will be nothing short of a minor miracle..
I have stipped it down to expose the motor turntable and tensioner pulley ..
..and yes the belt in this WAS plastcised and after a couple of rotaions turned to glop ..and bound to all drive surfaces ..
So ..I've stripped it down and cleaned all that goopy rubber out ..but the ususl problems ..what to do for a belt ?
Well I had a few left over from the days of VCR sericing ..
Found on roughly the right diameter ..but a bit thicker ..but worse ..3mm wide and I need 2mm at most ..
stretched it round a plstic peanut butter pot ..and with a blade removed from a disposable razor ..proceded to trim a 1mm circular strip off the edge of the belt ..
my eyes hurt after spending 20 minutes wearing a jewellers eyepiece..but I looks about right ..
see close up..
only time will tell ..
but I may well reassemble it to be presented with a lump of junk.
rgds
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-09 @ 20:20

Oh my. Yes, please. Do a complete cleaning of the insides and especially the heads before putting this back together... The self-made belt looks good, let's hope it works. Oh god, please clean it thoroughly, I cant look at it :P,
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-09 @ 20:45

jaZz_KCS wrote:Oh my. Yes, please. Do a complete cleaning of the insides and especially the heads before putting this back together... The self-made belt looks good, let's hope it works. Oh god, please clean it thoroughly, I cant look at it :P,

..Got as much crud out of the mech as possible ...and cleaned the heads with iso ..
Partial reassembly ..insofaras the unit now accepts and ejects floppies ..
Tomorrow I will try and re-fit the main pcb which sits on top of the mechanism.
rgds
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Re: A couple of retros I'm working on.

Postby Hamby » 2018-2-10 @ 08:17

Hey, Vipersan...

I don't know why, but I've been following this on ebay for a long time. It's an 8 mb memory card for a T4600.

I don't know if it would be of any use to you, or if you could get it, it being in the US, but just in case it might be of interest:
https://www.ebay.com/itm/8MB-Toshiba-T4 ... 1438.l2649
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-10 @ 10:00

IIRC, the T4500C also uses these types of DRAM cards that have the same dimensions of PCMCIA cards, albeit with a different connector at the end.

I think it's the only way to upgrade the memory on the 4500C and 4600C, as they do not seem to have any normal SIMM slots besides these DRAM expansion slots.
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-10 @ 10:52

Good news and bad news to report this morning ..
The Keyboard kindly aquired by JZ arrived ..so I wasted no time fitting it and it tests just fine..
Pic attached
My T4500C was examined closely ..and I found it came eqipped with a 4mb upgrade card ..
..and the bad news is ..
although the motor on the T4500C floppy now appears to run ..
It may be labouring ..
perhaps the belt is a bit tight ..?
However ..on boot the drive isn't even recognised by the bios as A:
So I rather think the floppy control board is damaged ..
I'll keep a lookout for a non working EME278TY ...
I may be able to make a hybrid worker .
Alternatively I could try and fit an ultra slim ..which has the same number of connections (26) ...but uses a different width ribbon.
rgds
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-10 @ 10:58

It already arrived? That was quickly shipped by DHL, nice.
Maybe you could find another 2/3rds drive, or even use a superslim. You can sandpaper the connector, and use layers of paper until the connector is thick enough to stay in the slot, if it is too thin. I did that on the old compaq. The cable I altered for it was way too thin and slid out of the connector. I put several layers of paper parallel to it, thickening it up. If it is the width that is different, then you probably have to find another cable.
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-10 @ 11:05

jaZz_KCS wrote:It already arrived? That was quickly shipped by DHL, nice.
Maybe you could find another 2/3rds drive, or even use a superslim. You can sandpaper the connector, and use layers of paper until the connector is thick enough to stay in the slot, if it is too thin. I did that on the old compaq. The cable I altered for it was way too thin and slid out of the connector. I put several layers of paper parallel to it, thickening it up.

Problem is JZ ..sandpapering it wont help ..the two cables are different widths ..at the floppy end.
I'd actually have to make my own ribbon ..or aquire one of the correct width and fold to fit ..
The photo shows what I mean though these are not the drives in question.
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-10 @ 11:06

Crap. Proprietary width. You could cut it before it gets wider, albeit it will surely be too short then. Back to the drawing board.
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-10 @ 11:10

jaZz_KCS wrote:Crap. Proprietary width.

The good news tho ..is they are pin for pin compatible ..
I've checked with both service manuals ..so I just need a length of 26 pin ribbon I can fold to suit..
rgds
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-10 @ 15:17

So..Im having trouble finding 26 pin ribbon cable ...
However it is possible to get 40 pin both forward and reverse (this would avoid sanding) ..
It is available from China in various lengths ..and relatively inexpensive.
https://www.ebay.co.uk/itm/40-Pin-FFC-F ... 9zxQRtom8Q

The 1mm is important as this is the needed 'pitch' I believe..?
Please feel free to correct me here ..
So ..I may well order one of each 'inversion' and roughly measure the length I need ..then trim to 26 pins with a sharpie
What do you think JZ ?
rgds
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-10 @ 15:56

All I can say is: Theoretically yes.
When I was in need of one, I looked throughout the basement and actually found 10cm of 26pin flat cable.
It was the wrong direction and not thick enough. Therefore I had to sandpaper it and "reinforce" the last 3 mm so they would stay in the connector (since it was a connector without a lock mechanism, purely holding with it's girth.)

With the cable you linked, you would have the right "direction" and thickness, it seems like. For that price, might as well give it a go. If you already know that it's standard pinout there's actually no reason I could think of why this wouldn't work.
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-11 @ 13:15

Spent the morning assembling my XT-IDE kit ..
without instructions ..but most of it is straightforward ..
I will need to get info before setting dip switches and jumpers etc..
Hopefully there will be a link on github ?
anyway ..my eyes need resting now ..
here it is assembled.
..obviously not yet tested..
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-12 @ 13:07

Bit of a disappointment ..
Got my Micromaster 1000 working with the software found on an old Toshiba T4900CT laptop ..
Flashed an Atmel 1024 no problem..
but the real reason I wanted to get this old programmer working was to program this chip type ..
MCM 68764C, 8K EPROM, equivalent to 2364 ROM
I have 6 of these chips and what makes them special is that these 2nd generation eproms are totaly pin compatible with the roms in a Commodore 64 .
In other words an 8k device in a 24 pin package ..which can be used as a straight swap for the 2364 ROM ...thus ..no adapter needed.
So I guess I'm either missing the neccessary library .lib file for this Motorola device or it is simply not supported electrically..
Does your programmer support this device Ian ?
Most of the modern programmers certainly wont entertain such a device which has almost disappeared into the fog of time..
I guess I'd have to spend a lot of money to get a programmer that will do ALL devices.
doh!
rgds
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Re: A couple of retros I'm working on.

Postby IanB » 2018-2-13 @ 15:14

Vipersan wrote:but the real reason I wanted to get this old programmer working was to program this chip type ..
MCM 68764C, 8K EPROM, equivalent to 2364 ROM
I have 6 of these chips and what makes them special is that these 2nd generation eproms are totaly pin compatible with the roms in a Commodore 64 .
In other words an 8k device in a 24 pin package ..which can be used as a straight swap for the 2364 ROM ...thus ..no adapter needed.

My Micromaster LV48 won't do them but the older ISA bus based Expro 80 appears to support them!

mcm.jpg

If you already know what you want programmed into them I can do that for you sometime.
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Re: A couple of retros I'm working on.

Postby Hamby » 2018-2-13 @ 20:27

IanB wrote:
Vipersan wrote:Ignore my PM Ian ..
I just ordered one stick from Germany ..
It may be a while ..but I'm in no hurry to start this mod ..

Got mine from Germany today, they work fine, even in the two 2MB slots. Obviously 6MB is wasted in those slots but if anyone wants to do the full 2+8+2 mod, not just the 8MB add on I documented so far and can't find 2MB sticks these would be OK.

samsung.jpg


Any reason one couldn't install an ISA based memory expansion card like for an 5160XT or 5170AT for additional memory beyond the 14mb limit?
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-13 @ 21:54

So this is my attempt at a battery pack for the T4900CT ..
Like the original it is rated at 2600mah/12volts ..and consists of 10 nimh cells ..
they were bought from bay for £13 ...and are AA sized ..and probably a lot less material than the original 4/3 cells ...therefore wont hold a charge as long.
You can see the pack does not occupy as much of the battery case as the original cells did.
I poked a hole in the cells wrap ..and inserted the temp sensor into a short length of shrink tube which was then inserted into the hole I made.
The T4900 has trouble now calculating charge remaining time ..though it does beep alarm 5 minutes from shut down ..and the pack takes approximately 2 hours to display 100% charged ..though this may not be accurate.
I left the laptop on battery to see how long until the 5 minute warning beeps sounded ..
90 minutes ..
So 2 hours to charge ..90 minutes battery life.
I really didn't expect miracles ..but am pleased with the result.
The pack never gets hot only moderately warm to the touch ..
I guess you could call this a result.
rgds
VS


..further tests have shown I can get around 2hrs 30minutes of discharge time providing I allow the laptop to turn off the screen after 10 minutes until mouse movement or key press reactivates it.
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-13 @ 21:59

IanB wrote:
Vipersan wrote:but the real reason I wanted to get this old programmer working was to program this chip type ..
MCM 68764C, 8K EPROM, equivalent to 2364 ROM
I have 6 of these chips and what makes them special is that these 2nd generation eproms are totaly pin compatible with the roms in a Commodore 64 .
In other words an 8k device in a 24 pin package ..which can be used as a straight swap for the 2364 ROM ...thus ..no adapter needed.

My Micromaster LV48 won't do them but the older ISA bus based Expro 80 appears to support them!

mcm.jpg

If you already know what you want programmed into them I can do that for you sometime.

Thanks Ian ..
I shall keep that in mind..
Not sure what I intend to do with them yet ..but it will be commodore related ..
VIC20 C64 or even PET ..
I may well take you up on your kind offer ..but will keep looking for suitable programming hardware myself ..in the meantime.
I will keep searching for an Expro 80 card ..now I know it will do the job and that you have suitable software..
Now I just want one ..
lol
;)
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