The Transam Triton Personal Computer
 

Has anyone heard of The Transam Triton Personal Computer it was launched in November 1978 as a Kit. I recently pull the one my uncle built from my out house were it has been stored in not ideal conditions for over 20 years.

This computer was an intel 8080-based single-board microcomputer running at 2MHz, which could be expanded to use a motherboard and various expansion boards. The hardware was all 5V TTL, and typically based on TI 7400 series logic. The firmware was on 2708 EPROMs and initially comprised a 1kB 'monitor' providing the os function, and a tiny BASIC interpreter which only implemented integer numbers variables.

Full construction and software details for the kit were published in the November 1978 issue of Electronics Today International magazine.

There was also a user group which produced a number of news letters and for speed you needed to program in machine code, I can remember spending many hours typing in hex codes for games like space invaders and then many more hours find the mistakes.

I was thinking of bringing it back to life and wondered is anyone else has one and got it up and running again.

Advice would be welcome Gerald

Re: The Transam Triton Personal Computer
 

My first computer! As a 'young' lad I actually had to get a bank loan to pay for the kit of parts IIRC it was around £300 (256 BYTES of memory) and I had a great time both building it and learning assembly language when I took it away to sea with me (merchant navy) as 'entertainment'.

It would be great to see it up and running. No unusual parts although the character rom might be a sourcing issue if it's dud but there's no real reason why it should go wonky. All the other parts are 74LS logic and my kit had every IC in sockets so replacement should be easy enough if needed.

The article (magazine) is still available at the usual archive site too so no shortage of information.

Please post some pics of the innards!

Re: The Transam Triton Personal Computer
 

I believe forum member Timbucus has one of these, either an original one or a working (or soon to be working) replica. I expect he'll be along soon...

Re: The Transam Triton Personal Computer
 

Is that a recent picture or an old picture from the 80s? The wallpaper, telephone and condition of the Triton would suggest an old picture from the 80s.

What kind of condition is it in now?

I remember the Triton from the magazines back in the day, but never owned one. I was always put off the 8080 by the multiple voltage supplies.

I think you should try and get it running again, but don’t just plug it in and turn it on. Probably best to disconnect the power supply from the main board until you know the power supply is working correctly. The old systems running on multiple voltage supplies could suffer some serious damage if just one voltage is missing or over voltage.

I know at least one other forum member is working on reviving a Triton, so maybe it makes it a little easier knowing you are not going it alone.

Re: The Transam Triton Personal Computer
 

Welcome to the forum Gerald, you may be replying to messages but, your early ones will be subject to moderation so will appear in a funny order - do not think you are doing anything wrong - after a few posts that will go away and it will become closer to real time.

As pointed out above I have been creating a modern rebuild of the Triton with old components as I was lucky enough to secure a modern reprint of the PCB. There is a small group of us over on the big Social Network that are doing so and indeed some original owners / inheritors restoring their beloved machines so plenty of help available.

Here is mine which will next need a case:

Attachment 228004 you can see it running https://www.youtube.com/watch?v=QLoXojMKH7U and with a PI loader... https://www.youtube.com/watch?v=h-l5eP4cEFA

One of the members is restoring his and documenting it on his channel starting with a good background video https://youtu.be/0cSRgJ68_tM subsequent ones cover the repair. One of the other members is a bit of an expert having created a modern respin of the board (if anyone here fancies a challenge:)) and also the memory expansion you see on mine which allows me to run the 7.2 HUMBUG.

I would echo the advice to not be tempted to apply power. The original circuit relies on a Zener and under specified dropper resistor - the failure of which is pretty fatal to several chips and it is likely the three big Electrolytics if not physically leaking fluid are likely leaky electrically... even to a dead short situation. The transformer is unobtainium and would likely not be too happy with that event and the failed chips will add £100 to the repair bill.

At least the main chips; CPU, CLOCK, LS154 and the Video Chips U61/69 need to be removed as they can be a bit pricey to replace. U69's presence in the Apple 1 pushes up its value... IC70 is a single use PROM which if it has failed will make the machine seem dead. IC54 is similar but, even some failed bits as Jim had will just display corrupt graphics. Certain of the EPROMs are not preserved online so again will be worth checking and securing their contents before proceeding.

That said once the power is stable if indeed as is likely it is all socketed there is no reason it cannot be restored to full glory. If you can supply some photographs of the current condition inside and out then we can asses a route to help get it going safely.

The User Group magazine you mention was called Triangle and then just the Newsletter of the Triton User Group - many are missing so if you have any some scans would be appreciated! http://www.computinghistory.org.uk/d...November-1979/

Re: The Transam Triton Personal Computer
 

Hi Tim, that keyboard was mentioned recently on the retro-comp google group.
https://groups.google.com/g/retro-comp/c/qBgAijt8ZOs

Re: The Transam Triton Personal Computer
 

Ha Ha - busted - look at the part number on the chip in the photo on the chat :)

Re: The Transam Triton Personal Computer
 

Hi Good to see the Triton lives on.

Based on a Look see today I think getting mine back up and running is going to be a major project.

I did a lot of modification which of course I documented very well (NOT), took out the original 3K memory and upgraded to 48K using memory cards from old barcode monitor/pestel terminals, replaced the power supply with a switch mode one, moved the 8k basic and assembler to 8K eproms, and designed and build a Floppy Disk Controller based on the Western Digital FD chip and a Z80 co processor to do the I/O.

I think a new modern reprinted PCB would be good, and can you still get the original static memory chips.

This is what mine look's like today

Re: The Transam Triton Personal Computer
 

That does look like a fun project! Are those 8" drives? If you have some custom ROMS with a CPM for it then preserving those will be worthwhile...

At least you still have the original Mullard C280 caps where the onboard PSU was...

It is still possible to get the original chips although it is becoming harder and expensive to put much capacity on. I would be tempted in your case to consider just securing a few to get it working and restore the expanded functionality with your cards or a modern replacement - especially if as it seems your expansion connector merely replicates the Triton expansion port.

The two modern respin boards switched to using 2114 which are slightly easier to get. But, it seems most people use a RAM expansion anyway more because as you found BITD there is a need to have 8K EPROMS for 7.2 HUMBUG and BASIC.

The photo system on here removes all good quality so some detailed shots close up across the whole board should be made to preserve the as now stage. Even underneath as you may have cut tracks etc. If you are prepared to share them I am sure people here will help identify the custom work...

The decision on how to proceed for you now moves to do you want to restore the original board and perhaps use a new one longer term to rebuild your original custom.

There is a member with a heavily modified MK14 that has suffered the same decision process.

It may also be possible perhaps to do both and restore the board but, build a separate power supply for your expansion systems. I suspect the Switch mode may be a project all by itself anyway.

Re: The Transam Triton Personal Computer
 

It is grainy but, I can see you are missing IC70 perhaps in order to modify the addressing. Most expensive chips are in sockets and those that are not are all usually easily available.

There is a project running on another thread to get a 2708 programmer running so we might be able to knock you up a single older EPROM that is known good so yours can be put aside and not risked.

Re: The Transam Triton Personal Computer
 

I notice you mention the Assembler - if you have an 8K EPROM with TRAP on it then please be careful it may be the only one in the world... In fact I can see it in the lower left - you have just made a lot of Triton owners very happy if that can be read and preserved.

Re: The Transam Triton Personal Computer
 

One thing I notice is that the EPROMs all appear to have 16-bit hex checksums written on the labels, which will be helpful if you get to the point of needing to know if they are still OK.

Re: The Transam Triton Personal Computer
 

Yes Ian and I were just chatting to check if they are the same as the known ones as there are a couple of 7.2 variants. The three that we do not have are the FAST VDU (CS=5D82? damn the lo res pics), the BASIC P?? (no checksum) and obviously TRAP whose checksum I cannot read.

Re: The Transam Triton Personal Computer
 

Easier to look at the name on the bottom right of the pcb.

Re: The Transam Triton Personal Computer
 

Been in the loft and found these four Independent user group booklets each around 45 pages of A5 put out on Nov 1982 Feb 1983 May 1983 and Aug 1983.

Booklet number three has the list for subscribers to this group including my uncle Terry its Approx. 150+ people from all over the UK and includes people from Switzerland, West Germany, Spain, Belgium, Norway, Denmark, Canada, and Finland. so looks like the good old Triton got around a bit in the 80's

With regard's to getting my Triton going I think the first approach will be to see if I can read the EPROMs. I did have a EPROM programmer which plugged into the Triton via my added I/O port (blue connector left hand front) but that would require a working Triton and the SW to drive it. Have not found my EPROM programmer so far but did find my intel 8080 book.

So looking for a EPROM reader / programmer , I also remember the 2708 had a strange program sequence were you have to cycle n times depending on the program pulse width and you needed a high program pulse voltage too (+25V).

Re: The Transam Triton Personal Computer
 

A few thoughts...

I remember the Triton article in ETI but it's one machine I never owned. Like one other poster here, I found the 3 power rails of an 8080 to be a pain and would have gone for a Z80.

But I still have my Intel MCS8i (early 1970s, paper tape based with a lights-and-switches panel) and MDS800 (early 1980s? 8" floppy based) development systems and all the manuals. And an Intel data book covering the 4004 up to the 8085 on the shelf.

I also have a device that can read (and program, according to the manual) the 2708. I used it to read out the EPROM in my Softy, so it seems to work. To be honest if I was making a copy of the Triton now I'd put the firmware into more common and cheap devices like the 2764, even if I wasted 7/8th's of each chip, and make little adapter boards for them.

Thinking about the keyboard, I recently needed a keyboard for an obscure terminal. I used a DEC LK201 (the keyboard from the VT220, etc) with an Arduino Micro as an interfaace. Now microcontrollers are not really my area but I am pretty sure I could have had a parallel interface on the output side without much work rather than the serial one needed for the terminal. And I think it's not too hard to use a PS/2 keyboard (USB keyboards are another matter, although maybe the Arduino Due can handle that). When I've tidied up my lash-up (which looks better even now than than that amplifier in the audiophool thread) I'll post some details of my interface in the appropriate thread.

Re: The Transam Triton Personal Computer
 

Nice systems - you always seem to have the best ones :)

Ian's board does put them mostly on the expansion card (as BASIC and TRAP need 8 EPROMS each!), as did Gerald's it seems so you only need two on the board - see note later on this post.

Sounds similar to the adaption I made to the Sirius PI Programmer project on another thread (which uses opto isolators - does your arduino solution?

Seriously though as Mark has spotted; the Triton owner Ian I mentioned, had put a lot of hours into the design of a keyboard PCB which he has had made, but at the time the specialist decoder chip was unavailable. I had spent a long time learning how to program PIC's by studying Karen's code in order to adapt a Dragon32 keyboard for my Triton. So we pooled our resources and made a ready to go replacement that looks more authentic and has a few tricks up its sleeve - more news soon.

Lovely - I don't think the ones from the 1990's are in the Nat Museum collection - either way they do not make the contents public so a scan to Archive.com would be a great way to preserve these.

As Tony mentioned he has a way to read 2708 at a push so I am sure he would help out if we asked nicely. It is likely the two with the arrows for MON are just variations of the ones we already have - perhaps even just some hooks for your floppy drive and a changed serial port speed. In that case securing the two 8K TRAP/BASIC ones off the board along with the two in the middle FastVDU and the BASIC (no CS but extension perhaps?) leaves you with enough to boot and use the machine at much lower risk.

The 8K ones could be read in any cheap modern programmer like the TL866 widely available - one of them may be useful to you to get the Triton running and then use your old programmer for any 2708 work...:)

Tony also mentions the keyboard and yours looks impressive - would like to find out more about that...

Re: The Transam Triton Personal Computer
 

I have a couple of ay-5-2376 keyboard encoders if there is any chance of getting a pcb, though it would probably be for my microtan rather than a triton.

Re: The Transam Triton Personal Computer
 

There is definitely already a third-party Arduino library for communicating with PS/2 keyboards, which as you rightly say could then pass through to a parallel port for communication with a system like this.

The thing about this approach is that there are some really nice old PS/2 keyboards with decent keys still out there dodging landfill, so you have a huge range of old keyboards to choose from if you go with a PS/2 connection.

Re: The Transam Triton Personal Computer
 

The PCB would not be of any use with an original decoder - it is 756 compatible only in the output edge connector and signalling. The matrix and pinouts are totally different - sorry.