A couple of retros I'm working on.

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

Postby Hamby » 2018-2-14 @ 15:32

Vipersan wrote:
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 ..



Maybe make a dual SID emulator ISA card for your T5200?
https://www.youtube.com/watch?v=3WCUxF4 ... freload=10

HardSID: https://en.wikipedia.org/wiki/HardSID
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Re: A couple of retros I'm working on.

Postby tegrady » 2018-2-14 @ 19:02

Vipersan wrote: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..


Can you buy the XT-IDE pre-assembled?
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-14 @ 19:42

Indeed you can ..though expect import duties if you are outside the US
https://www.ebay.co.uk/itm/NEW-XT-IDE-r ... 100623.m-1
rgds
VS
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-15 @ 17:19

Back with the T4500C
I managed to buy a 3/4 height slim floppy from Germany ..
Yes it was a bit pricey but claimed 'new' old stock.
Chances are this one is also belt drive ..
model number EME278TB.
This one came with a grey bezzle which hopefully can be removed for fitting..
more importantly has a wide 'ZIF' which I prefer to call a MIF socket
Max insertion force ...which meant assuming I could remove the soldered flex cable from the original FDD ..without damage ..and clean it up suitably .
Could be reused for the MIF socket .
Well it did come off with a hot air station and the contacts cleaned up nicely ..
It took a while to insert this reclaimed cable into the MIF socket ..but eventually ..
Job done ..and it works.
I now have a floppy on this old laptop.
rgds
VS
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-15 @ 20:15

Not perfect ..the FDD flap is grey not cream ..
The LCD info strip is only partially functional ..
but ..it is working and reassembled ..
Another to cross from the list
:D
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-18 @ 11:25

Not much I can do today ..
Waiting for my 486 cpu and rainbow ribbon cable to continue the 5200 mods..
So decided to take another look at the 3200sx and how it mght be used without plasma screen ..?
But ..I didn't want to remove the connections for the screen ...errr..just in case I ever found one.
Well that modem compartment underneath makes a ferfect flace to hide cables.
Lift up the hard drive..
unplug and remove the modem ribbon ..and re-route the display cables ito that empty space ..
This means the top half of the case can now be re-fitted (see pics)
The keyboard no longer fitted on account this has been repurposed for the 5200 ..but of course..
The 3200sx can be used with an external keyboard..
broke out the plastic case plug and tried an old viglen KB with an AT connector ..and the bios allows booting directly to external monitor ..

Fitted a new 3.6v lithium battery ..and powerd up ..
Nice ..it all works ..and I'm in DOS 5
I am still using the original BIOS for now ..but I will be trying a modded 3200sx bios ..later.
Which one is going to be best for me Ian ?
rgds
VS
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-18 @ 11:50

Next question ..
Can I upgrade the memory ?
..and if so ..with what ?
I do have a few old 30 pin sticks ..but I also know from reading that the 3200sx can be mighty picky about this ..
I've attached a photo of what I have ..
Sadly not much to choose from ..
I figure these need to be fitted in pairs ..and I assume left > right is the pairing?
starting at the back near the hard drive ?
Over to you with this one possibly JZ ....
I have tried a couple at radom ..but all I ever get is parity errors at boot ..enter setup etc etc ..
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-18 @ 13:22

So it would seem the T3200SX only accepts memory modules with parity ?? (unmodded)
These can be 1mb or 2mb only ?
Is there an easy way to determine what sort of modules I have ?
as I also found this posted on the net ...by a guy called SAM
---------------------------------------------------------------------
I have discovered out how to make a standard 2 Meg or 1 Meg 30 pin SIMM work in the T3200sx. What you have to do is cut the trace that is connected to the CASP line (pin 28) and connect that to the CAS line (pin 2). This will result in a 1 Meg module that will work with out the parity error that you will get with out this modification. I have noticed that your 2 Meg Toshiba SIMMs have only 4 chips on them instead of the usual 9 or 3. It would be interesting to try and find the datasheet for the chips and try and figure out the pinout of a 2 Meg Toshiba SIMM. In my T3200sx my 2 Meg modules have 6 chips and I have only been able to find the datasheet for 4 of them. I think that the other 2 are the parity chips but I am not sure. I have found out that pin 19 is grounded on the 2 Meg Toshiba SIMM. I am also guessing that pin 28 on the 2 Meg Toshiba SIMM is A10 but I am not sure. By the way feel free to post this information on your website where ever you think that people will read it.
--------------------------------------------------------------------------------------------------
Which gets round the Parity problem..
anyone tried this ?
rgds
VS
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-18 @ 13:45

Some close ups of the 30 pin simms I have ..
Odd numbers of each
5 .. 3 and 1
rgds
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-18 @ 14:00

You may have forgotten, Vipersan, but I did this a few pages back :)

viewtopic.php?f=46&t=57883&start=200#p646793

Basically take the last one's you photographed. They look like they could be made compatible.

Basically "what you have to do is cut the trace that is connected to the CASP line (pin 28) and connect that to the CAS line (pin 2). This will result in a 1 Meg module that will work with out the parity error that you will get with out this modification"

I did this as you can see in my pictures (although it's very hard to see the tiny trace cut I made, you have to zoom in)
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-18 @ 14:03

..and these of which I only have 2
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-18 @ 14:04

I am pretty sure it will work with the 9-chip ones of which you have 5. Not sure about these, but why not try as well?
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-18 @ 14:05

jaZz_KCS wrote:You may have forgotten, Vipersan, but I did this a few pages back :)

http://www.vogons.org/viewtopic.php?f=4 ... 00#p646793

Basically take the last one's you photographed. They look like they could be made compatible.

Basically "what you have to do is cut the trace that is connected to the CASP line (pin 28) and connect that to the CAS line (pin 2). This will result in a 1 Meg module that will work with out the parity error that you will get with out this modification"

I did this as you can see in my pictures (although it's very hard to see the tiny trace cut I made, you have to zoom in)


Done so many mods and fixes lately ..I get confused ..lol
and add to that the senior moments.
:D
cheers buddy.
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-18 @ 14:31

just found your mod photos JZ ..and I then looked at one of my 9 chip 'bricks' ..lol
Curiously I dont think I will need to cut the trace to pin 28 ..as it looks un-linked ??
pin 28 goes to a link pad which can be solder linked ???
see the poor close up.

There is also another link/bridge solder pad on pin 29 .. linked to pin 26.... DP/QP
no idea what it is for ..(also unlinked)
Perhaps the same memory simm is sold as parity or non parity ..depending on one or both of those links ?

If I read this right the unattached pin 28 would indicate these are already NON parity ???
rgds
VS

Just found this ..which might shed some light...
https://allpinouts.org/pinouts/connecto ... mm-30-pin/


Problem is ..these may be 4mb simms ..so not acceptable to the 3200 ?
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-18 @ 15:25

So popped a blob of solder on 2 simms linking the pads discussed above this effectively links pin2 to pin 28 ..
popped in the 2 simms and the 3200 booted straight into DOS 5 without complaint ..
No idea if these simms are active..
certainly no change in the extended memory checked at boot
still showing 384K
..but at least there are no parity errors flagged up ..
Now what ?
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-18 @ 17:32

Tried to catch the vga bios info for you Ian ..but either I'm too slow or not rebooting in a way that shows it ?
rgds
VS

btw ..
which bios is the most recently modded for the 3200sx (most versatile that will accept any Hard drive ?)
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Re: A couple of retros I'm working on.

Postby IanB » 2018-2-18 @ 19:29

Vipersan wrote:So popped a blob of solder on 2 simms linking the pads discussed above this effectively links pin2 to pin 28 ..
popped in the 2 simms and the 3200 booted straight into DOS 5 without complaint ..
No idea if these simms are active..

If you have connected pad 2 to pad 28, that's not what the mod requires and may have messed up the signals stopping the SIMMs from being detected altogether, although it looks like that solder link is designed as part of this mod. I think there should be another link that must be broken as well to isolate pad 28.
Before the mod you will have pad 2 connected to some chips and pad 28 connected to others, after the mod pad 2 should still be connected to it's original chips and also to the chips that originally went to pad 28. Pad 28 itself should be completely isolated with no continuity to anything. The pin 26/29 mod is for SIMM slots that don't have separate data in and data out for the parity bit and the link connects them together. I don't know if the T3200SX requires this.

Vipersan wrote:btw ..
which bios is the most recently modded for the 3200sx (most versatile that will accept any Hard drive ?)

this one here (beta3):

viewtopic.php?f=46&t=57998#p643529
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-18 @ 21:15

Hi Ian ..
flashed one of my 1024 chips (yes they did finally arrive from China)
with T3200SX Award 89 BIOS patch Beta0-3
..and yes it does boot just fine ..but does not run the 40mb Conor ..(DOS 5)
Hence missing operating system ..
???
I guess the new bios just doesn't like the geometry of these ancient legacy drives ..
rgds
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-18 @ 21:59

I've tried to represent what I believe to be the layout of the 9 chip simm with the solder bridge pads ..
normally open between 2 and 28
rgds
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Re: A couple of retros I'm working on.

Postby IanB » 2018-2-18 @ 22:10

Vipersan wrote:..and yes it does boot just fine ..but does not run the 40mb Conor ..(DOS 5)
Hence missing operating system ..

This appears to be the same problem you had with the T5200. I have a 64MB compact flash and looked into this a bit more.
This has a native drive shape of 490 cylinders, 8 heads and 32 sectors per track as read directly from the CF but when the shape is read via the BIOS (in this case XTIDE) it comes back as 124 cylinders, 16 heads and 63 sectors per track. This amounts to about the same capacity (125440 sectors vs 124992 sectors) so will still give about the same storage but with a different geometry so my initial suspicion when we discussed this previously was correct. Those very small drives usually have 17 sectors per track so the geometry will definitely be translated to 63 sectors per track when connected via XTIDE.
I don't know if this behaviour with small drives is standard with all translating BIOSes or just a feature of XTIDE but reformatting and reinstalling should make it work again.
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