7th Mar 2021, 12:47 am | #21 |
Pentode
Join Date: Mar 2021
Location: Liphook, Hampshire, UK
Posts: 125
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Re: The Transam Triton Personal Computer
The Keyboard on My Triton came from an old CA (Computer Automation INC) Syfa systems VDU. It has a nice action as it used hall effect key switches I hope it still works.
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7th Mar 2021, 3:48 pm | #22 |
Octode
Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
Posts: 1,363
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Re: The Transam Triton Personal Computer
I am sure it can be repaired - you seem to have a few more than needed so like my BBC - I had to swap one of the relatively unused F keys for a main one. Thanks for the detail.
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7th Mar 2021, 9:05 pm | #23 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,560
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Re: The Transam Triton Personal Computer
Briefly OT, a guy over on VCFED found a load of Acorn keyboards lying on someone's driveway and rescued them. In Oz, unfortunately, but you might be able to persuade him to put a keytop or two in the post.
http://www.vcfed.org/forum/showthrea...n-side-of-road |
7th Mar 2021, 11:10 pm | #24 | |
Pentode
Join Date: Mar 2021
Location: Liphook, Hampshire, UK
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Re: The Transam Triton Personal Computer
Quote:
I am working towards getting a hex dump of these EPROMS and see if they work, I have the Triton emulator written by Robin Stuart up and running on a Raspberry PI 3 and it works well. |
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8th Mar 2021, 6:38 pm | #25 | |
Pentode
Join Date: Mar 2021
Location: Liphook, Hampshire, UK
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Re: The Transam Triton Personal Computer
Quote:
Thank God I wrote the Checksums on the EPROMs when I programmed them more than 30 years ago. These EPROMs are HN482764G with a 250ns access time looking at the data sheet from Hitachi there in no mention of the data life but they have a wide storage range from -65 to +125 C. When I read them with my PIC processor reader after slowing it down to deal with the access time I get the correct checksums for both the BASIC and the TRAP (Triton Resident Assembly Language Package). So I am confident the data I have from them is correct but neither work on the Triton emulator written by Robin Stuart. I know I modified the BASIC so it could be used with my floppy disk file system. but can not remember if I modified the TRAP. Given it may be the only copy out there I will have some work to do to disassemble it and find out what the problem is. But given I get the correct checksums on both EPROMs looks like Hitachi did a good job as they still work, be interesting to see how they preform in a real system at Tritons full clock speed. Next Stage is to read the four 2708 EPROM's and use these with the emulator, I hope these are in as good shape as the HN482764G are. But now we have to deal with the multi rail power requirements of the 2708. I did see a post on here regarding 2708 EPROM Power Sequencing so this is of concern. |
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8th Mar 2021, 7:16 pm | #26 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,560
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Re: The Transam Triton Personal Computer
If you have potential access to an EPROM programmer you may wish to consider 'refreshing' the original 2764 EPROMs to set the data fade 'clock' back to zero - but first, stash copies of the code you've read out from them absolutely everywhere.
A less fraught approach (than over-programming the original devices) would be to obtain some more 2764 EPROMs and copy the contents into those and keep them as your 'hard' backups. As you may have noticed there is another thread concerning a project to replicate the old SOFTY 1 2708 reader / programmer, but maybe you can read them with your PIC / Pi hybrid if you can somehow juggle all those exotic supply voltages. |
8th Mar 2021, 9:46 pm | #27 | ||
Octode
Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
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Re: The Transam Triton Personal Computer
Quote:
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11th Mar 2021, 1:13 pm | #28 |
Pentode
Join Date: Mar 2021
Location: Liphook, Hampshire, UK
Posts: 125
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Re: The Transam Triton Personal Computer
Having now built a multi rail power supply with a 7805 and two zener diodes to achieve the +5 v -5v +12v voltages required by the 2708 Eproms .
some mods to my raspberry pi reader program the four 2708 1k Eproms read ok and produced the correct checksums. info here:- https://sites.google.com/view/transa.../eprom-reading I now have all Eproms backup and using the emulator written by Robin Stuart after some mods to the memory access they work !!!! on the emulator at least. they can be down loaded from hear:- https://sites.google.com/view/transam-triton/home. Now the task is get the real machine up and running I do however need the graphics prom or a hex dump. |
11th Mar 2021, 2:10 pm | #29 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: The Transam Triton Personal Computer
Brilliant, well done - and you deserve a medal for managing to keep it all connected while using those Arduino-style jumper leads as they are notoriously unreliable.
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11th Mar 2021, 2:49 pm | #30 | |
Pentode
Join Date: Mar 2021
Location: Liphook, Hampshire, UK
Posts: 125
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Re: The Transam Triton Personal Computer
Quote:
Thanks, thats the first time I used the Arduino-style jumper leads as I was given these some time ago but never used. I would normally use the good old veroboard. |
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11th Mar 2021, 3:54 pm | #31 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: The Transam Triton Personal Computer
What sort of device is the graphics PROM which you need?
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11th Mar 2021, 6:13 pm | #32 |
Octode
Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
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Re: The Transam Triton Personal Computer
That is excellent work Sir - I shall try the TRAP on my Triton as soon as I can get it set up. The images you need for the two PROMs are in the ZIP attached:
IC54 - 74S287 (256 x 4bit) IC70 - 74S472 (512 x 8bit) If you are struggling I am sure Ian on the FB group would burn you one. It is possible that Sirius has a programmer that can do them as well for a UK source - he is a very helpful chap like that. Tim |
11th Mar 2021, 6:42 pm | #33 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: The Transam Triton Personal Computer
I can do those devices as long as they are Nat Semi (DM prefix) and not Tesla (MH) prefix - and as long as they are blank and have not previously been programmed, but it sounds like the other party may already have the code and a machine to test them in?
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13th Mar 2021, 5:59 pm | #34 |
Octode
Join Date: May 2018
Location: Northampton, Northamptonshire, UK.
Posts: 1,440
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Re: The Transam Triton Personal Computer
My (a bit old now) Dataman 48XP can also do the National Semi DM54/74S287 and DM54/74S472.
I can also usually do Tesla MH74S287's (but no other makes 74S472's) on a later (& different Elnec-designed) Dataman 48Pro-series, when I can access it again. Although there may also be some other, different-numbered, equivalents, here: https://www.mikesarcade.com/cgi-bin/...ge=PromRef.txt that these programmers will do. You may also be able to substitute an EPROM / Parallel EEPROM (You can these down to 45ns, although mainly larger / more modern CMOS types, and often quite cheap - as little as 50p for W27C512, (actually an EEPROM)) for these - like has often been done with C64's unreliable custom PLA (Although it does mean converting logic equations into an all-combinations lookup table and some pin-adapters) |
15th Mar 2021, 4:52 pm | #35 | |
Pentode
Join Date: Mar 2021
Location: Liphook, Hampshire, UK
Posts: 125
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Re: The Transam Triton Personal Computer
Quote:
I have also found the Original Transformer 8.5, 12-0-12 volts this I believe this was custom made for the Triton and is hard to come by now. There is a photo here https://sites.google.com/view/transa.../photo-gallery its looking a bit old the 8.5 volts is unusual but I understand this was done to keep the heat generated by the linear voltage regulator (IC1 LM323K) down. But I do seam to remember this did get quite hot which is why I added the external switch mode power supply. |
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15th Mar 2021, 8:56 pm | #36 |
Octode
Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
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Re: The Transam Triton Personal Computer
Yes indeed the 8.5v is to reduce the strain on the 5v rail. Mine is running on a 9V transformer (as you say the real one is 'rare') and I have a bit bigger heatsink on the LM323, it seems to cope quite well but does make a nice handwarmer - the diodes on the Bridge circuit get quite toasty as well, as does the dropper resistor for the zener!
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15th Mar 2021, 10:26 pm | #37 | |
Pentode
Join Date: Mar 2021
Location: Liphook, Hampshire, UK
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Re: The Transam Triton Personal Computer
Quote:
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15th Mar 2021, 11:41 pm | #38 |
Octode
Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
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Re: The Transam Triton Personal Computer
Mine is the respin that uses 2114 but draws about 1.4Amps on the 5V with 6 of them onboard (3K) and two 2708 for the level 7.2 HUMBUG. The Expansion board has 1 6264 RAM and now (thanks to you) two 8K EPROMS but has its own 5V regulator so not including the consumption on that.
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15th Mar 2021, 11:43 pm | #39 |
Octode
Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
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Re: The Transam Triton Personal Computer
I should add that that is powering the keyboard (uses a PIC controller chip) and the few chips to complete that and the expansion board for the AUtoRepeat and Beeper as well on the circuit.
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16th Mar 2021, 3:02 pm | #40 | |
Pentode
Join Date: Mar 2021
Location: Liphook, Hampshire, UK
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Re: The Transam Triton Personal Computer
Quote:
So the respin PCB is not the same design as the original PCB ? are there any unbuild original PCB out there ? I found the old Transam catalogue ( https://sites.google.com/view/transam-triton/transam ) from the summer of 1979 the 2111-2 back then cost £2.32 so the 3k onboard memory would have cost £55.68 then and would be £260 now. Its interesting to see the the VDU chip was the most expensive chip on the board at £15.95 in today money ( from this site https://www.inflationtool.com/britis...alue?amount=16 ) that would be a massive £74.51 to produce a display of only 64x16 thank God for Moore's law. I found a site in Canada that will do 24x2111-2 for £45 but they only ship to Canada and the USA so about the same price back in 1979. From the catalogue ( https://sites.google.com/view/transam-triton/transam ) the transformer only cost £7.00 I wonder how much it would be to have one made today given its unusual 8.5 volts secondary winding. |
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