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Old 27th Jan 2024, 1:14 pm   #141
SiriusHardware
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Default Re: An Enhanced MK14 (MK14E)

Chris, I'd like the built V1.0, with plastic 8154, if still available please. I'll PM you about it.

Quote:
I wonder why Sinclair switched to a DIN41612 for the VDU rather than an edge connector to match the MK14 ?
Sinclair moved in mysterious ways. If you recall, there was not one original version of the MK14 which had the signals required by the VDU tracked to the rear edge connector anyway - that didn't happen until Slothie's 'issue VI' replica came along.

Versions prior to issue IV didn't even have contact 'fingers' on the lower side of the rear edge connector - issue IV and V did but they weren't tracked to anywhere and users were expected to hardwire the necessary address, data, etc connections to them themselves. So it's not just that the connector types chosen were physically incompatible, the MK14 rear connector never had the signals required by the VDU available on it anyway.

The VDU (and in particular, how to connect it and how to provide it with an adequate amount of memory in which to run serious visual software) was very much an afterthought.
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Old 27th Jan 2024, 2:24 pm   #142
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Default Re: An Enhanced MK14 (MK14E)

Both of the ready built MK14E's have now found new homes.

Chris
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Old 27th Jan 2024, 8:25 pm   #143
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Default Re: An Enhanced MK14 (MK14E)

Quote:
Originally Posted by Timbucus View Post
I may be struggling with 3D orientation but, how does the backplane allow the VDU (I make a Lukasec repro) to be fitted as it ends up with the connections reversed doesn't it?
My guess is that the original vdu would be component side down if mounted above an MK14. The vdu board would then need to have the din connector on the track side of the board. You would need to check the orientation of the din connector on the edge of the MK14 matches the connector on the vdu and backplane.
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Old 28th Jan 2024, 4:56 am   #144
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Default Re: An Enhanced MK14 (MK14E)

Quote:
Originally Posted by Mark1960 View Post
Quote:
Originally Posted by Timbucus View Post
I may be struggling with 3D orientation but, how does the backplane allow the VDU (I make a Lukasec repro) to be fitted as it ends up with the connections reversed doesn't it?
My guess is that the original vdu would be component side down if mounted above an MK14. The vdu board would then need to have the din connector on the track side of the board. You would need to check the orientation of the din connector on the edge of the MK14 matches the connector on the vdu and backplane.
Although looking at Chris's MK14E

Quote:
Originally Posted by ChrisOddy View Post
>>
>>
Full details of the project can be found here: https://theoddys.com/acorn/replica_b...14e/mk14e.html
>>
Chris
It appears that his version of the VDU at least is component-side up, when mounted above the MK14E. And he'd said he tested with a close-copy of original SoC VDU board, so I assume his VDU board would have been made the same.

I doubt the backplane PCB is reversing the DIN41612 connection from left to right, as that would make the tracking rather involved.

So I can only presume he's done the left-to-tight 'mirroring' on his MK14E board, as he's intended it to be used with the backplane 'riser' board with the expansion boards above it (rather than sticking out the end as was originally necessary).
- Moving to the DIN41612 connectors means you wouldn't normally be wanting to plug Card-edge connector boards intended for original MK14 (were there ever that many. especially as original VDU board had the different connector) into the rear

But I guess Chris can clarify it a bit (I'll ask when I next see him in a couple of days, if he doesn't reply here first).
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Old 28th Jan 2024, 7:10 am   #145
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Default Re: An Enhanced MK14 (MK14E)

Chris might also have swapped the a and b rows of the connector, or the a and b rows of an original vdu might need to be swapped.
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Old 28th Jan 2024, 11:50 am   #146
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Default Re: An Enhanced MK14 (MK14E)

Not sure I've actually swapped any 'sides' over but anyway the backplane is described here: https://theoddys.com/acorn/replica_b...backplane.html

Hopefully that all makes sense !

Chris
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Old 28th Jan 2024, 1:10 pm   #147
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Default Re: An Enhanced MK14 (MK14E)

Thanks, Chris - As I suspected, the backplane is just simply 'straight-wired'
And you'd think that with it effectively folding over the connections, it would result in the VDU board would be upside-down.

However, I think I may now understand what's happening:
The Backplane board is all 64w 2row DIN41612 Sockets, with both the VDU and the MK14E Main board having Plugs.
Whereas, if you plugged an (original etc) MK14 VDU into the MK14, you would have needed to fit a DIN41612 64w 2row Socket to the MK14 Main board.
So by swapping from a Socket to a Plug, you automatically end up with the PCB footprint for the connector's rows being flipped (either left to right or top to bottom) in order that pin 1 of the plug always correctly goes to pin 1 of a socket when they are facing each other.

And, in summary, it is the fitting a plug rather than a socket to the MK14E Main board that makes this all work.
So I was kind of right when I presumed the expansion-bus tracking on the MK14E is kind of all flipped relative to the original edge-connector (that is no longer there), so that it all goes to the correct pins of a DIN41612 Plug to then effectively get flipped-back by the all-socket backplane for VDU etc compatibility.

It's similar to problem if you try to extend 2row IDC socket cables, by using a standard dual row header strip. When you need to flip the rows or columns (or use a rarer IDC cable mount Plug, that already has pins flipped).

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Old 3rd Feb 2024, 8:13 pm   #148
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Default Re: An Enhanced MK14 (MK14E)

I am (or will be) the new proud owner of one of Chris's early revision MK14E PCBs - unfortunately both of my currently owned SC/MP IIs are already allocated (one where it has always been, in my original MK14, and the other in my Issue VI which I don't really want to steal parts from because it is finished / completed to a fairly high standard and I really like it).

In accordance with forum requirements I have posted a request for another one in the 'wanted' section of the forum.
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Old 3rd Feb 2024, 8:55 pm   #149
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Default Re: An Enhanced MK14 (MK14E)

Hi Graham, I‘ve sent a PM
Quote:
Originally Posted by SiriusHardware View Post
I am (or will be) the new proud owner of one of Chris's early revision MK14E PCBs - unfortunately both of my currently owned SC/MP IIs are already allocated (one where it has always been, in my original MK14, and the other in my Issue VI which I don't really want to steal parts from because it is finished / completed to a fairly high standard and I really like it).

In accordance with forum requirements I have posted a request for another one in the 'wanted' section of the forum.
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Old 4th Feb 2024, 7:27 pm   #150
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Default Re: An Enhanced MK14 (MK14E)

Acknowledged RT, away from base just now so I will pick up the PM when I get back there later tonight, thanks.
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Old 8th Feb 2024, 7:46 pm   #151
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Default Re: An Enhanced MK14 (MK14E)

I've now received the MK14E and the SC/MP II which Realtime kindly made available for it. Thanks to both of you. I just need to find a good linear 5V supply for it before I can power it on.

Owen mentioned:

Quote:
Whereas, if you plugged an (original etc) MK14 VDU into the MK14, you would have needed to fit a DIN41612 64w 2row Socket to the MK14 Main board.
I have a habit / convention, wherever I have a main board (a) which can optionally have a secondary board (b) plugged into it, that the connector on the main board is always female and the connector on the secondary board is always male. That is so that if there is no secondary board plugged into the mainboard, the power rails and other driven lines are protected within the shrouded female connector. Thus, my original SOC VDU has a MALE DIN connector on it and the bridge board which goes between the issue VI edge connector and the SOC VDU has a FEMALE connector on its output end.

As supplied, my MK14E has a male connector on it, and I understand of course that that is because it is intended to plug into a backplane (on which the connectors are always traditionally female).

I'm not sure what I will do in this case - if the connections on the MK14E rear are numerically and position compatible with the pins of the SOC VDU I may just change the connector on the 'E' to a female one, or I may make a short 'bridge' board with a female connector on each end.
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Old 8th Feb 2024, 8:05 pm   #152
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Default Re: An Enhanced MK14 (MK14E)

Or you could add my backplane and the MK14E VDU !
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Old 8th Feb 2024, 8:08 pm   #153
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Default Re: An Enhanced MK14 (MK14E)

I'm in the unusual position of already having a choice of -FOUR- MK14 VDUs (Original SOC VDU, Ortonview, Realview, PiView).

Let me think about it.
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Old 9th Feb 2024, 3:58 pm   #154
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Default Re: An Enhanced MK14 (MK14E)

Quote:
Originally Posted by SiriusHardware View Post

>>
>>
Thus, my original SOC VDU has a MALE DIN connector on it and the bridge board which goes between the issue VI edge connector and the SOC VDU has a FEMALE connector on its output end.

As supplied, my MK14E has a male connector on it, and I understand of course that that is because it is intended to plug into a backplane (on which the connectors are always traditionally female).

I'm not sure what I will do in this case - if the connections on the MK14E rear are numerically and position compatible with the pins of the SOC VDU I may just change the connector on the 'E' to a female one, or I may make a short 'bridge' board with a female connector on each end.
You can't just swap a DIN41612 plug to a socket, as the pin numbers won't line-up. Although you could probably fit it to the underside of the board.
Using a pair of back to back soldered straight-pins sockets, probably isn't practical, as pin numbers wouldn't line-up to each other - So really need a PCB in-between to swap the rows over. Or have them face the same way and use Chris's Backplane PCB of parallel tracks / a cut-down version.

You can also get IDC-type DIN 41612 2 row connectors, so could also make a 'flexible' version that could be folded over (although VDU board would then be upside-down) - or maybe have the IDC ribbon long-enough to twist the cable 90degrees, so VDU is then correct way up.

Of course the original MK14 board didn't have provision for a DIN 41612 connector, but retro-fitting one to the pads of the edge connector made that suit a DIN 41612 socket pin-out (or at least match the DIN 41612 plug connections on the VDU board).
But IIRC, Chris's MK14E had to drop the edge connector (was there ever anything sold commercially that did plug directly onto this?) in favour of a DIN 41612 Plug, to allow plugging into a backplane and in the process the connections at the edge were 'flipped' in order for expansion board to sit the right-way-up above the MK14E.
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Old 9th Feb 2024, 4:24 pm   #155
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Default Re: An Enhanced MK14 (MK14E)

OK, that's obviously something I am going to have to look into in much better detail. I will probably end up making a female DIN -female DIN 'bridge' board with all of the connections rearranged on the way across.

Quote:
retro-fitting one to the pads of the edge connector made that suit a DIN 41612 socket pin-out (or at least match the DIN 41612 plug connections on the VDU board).
Even that wasn't entirely straightforward due to certain connections on the VDU landing on occupied connections on the MK14 side if the connections were made directly one to one. One example, the VDU CLK_IN signal wound up connected to one of the 0V fingers on the top side of the PCB. I drew up a sketch or table of the MK14 rear edge and SOC VDU connections and their relationship to each other if presented to each other one to one.

Of course, I can't find it at the moment.

Oh, wait, here it is:

Last edited by SiriusHardware; 9th Feb 2024 at 4:31 pm.
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Old 9th Feb 2024, 7:07 pm   #156
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Default Re: An Enhanced MK14 (MK14E)

And for some reason, the forum would allow me to attach the image but would not allow it to be clicked on. Very Odd. Let's try again.
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Old 9th Feb 2024, 7:11 pm   #157
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Default Re: An Enhanced MK14 (MK14E)

More to the point, I have just taken the MK14E for a short test drive by entering the now standard one-word display code via the keypad:
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Old 24th Feb 2024, 10:07 pm   #158
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Default Re: An Enhanced MK14 (MK14E)

I have upgraded the Expansion Board to Issue 1.1 which has an extra 16K EPROM in the upper 32K memory space.

https://theoddys.com/acorn/replica_b...ion_board.html

I have now successfully (with some help from Phil) managed to get NIBL-E with page3.sys running and with the new Expansion Board NIBL-FP as well.

I will soon have an alternative Backplane which will sit in-line (flat) with the Mainboard so that plug-in boards are vertical - this gives access to the Mainboard links etc.

I have a fully working Issue 1.0 Expansion Board and Backplane available if anybody is interested ? (drop me a PM)

Chris
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Old 25th Feb 2024, 4:29 pm   #159
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Default Re: An Enhanced MK14 (MK14E)

That's sounds a worthwhile upgrade - been looking at playing with these new developments - sure I can work out how to patch it into the 1.0 board. Finally got my MK14E running having found my spare SC/MP chips and proving one was dead the other works fine
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Old 25th Feb 2024, 5:29 pm   #160
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Photo attached, £30 incl postage ?
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