Acorn Archimedes A310 with VIDC monitor recommendations

[oo00Kman00oo]

The monitor I previously used on my Acorn Archimedes A310 recently died and I am now looking for a suitable alternative. At present I have it working on a 15" flat screen via the monochrome video output (definitely not desirable). I am not the most clued up person in the world when it comes to Acorn computers and was just wondering what my cheapest option might be. Looking for full colour and smallest possible display foot print. I would like if possible to avoid another CRT display. From my own research, the only real option I found was to buy an A310 -> VGA adapter (about £60 on eBay). I just wanted to know whether I might have missed a trick. As the machine has a VIDC enhancement, is it possible to just buy an RGB 9 pin -> VGA cable and to create a custom working mode?

Many thanks.

[geraldholdsworth]

My A3000 works fine, with the VIDC enhancer and a 9pin to 15pin adapter, into the LCD screen I have. I'm afraid that the best way is to just to try it.

[oo00Kman00oo]

I guess that should really be the first thing I try. Do you run in any particular mode? - Will try and get hold of a suitable cable and test it. Thanks.

[oo00Kman00oo]

Thanks, cable now ordered and will test on arrival. It does sound like it should just work with the VIDC.

[hubersn]

The monitor I previously used on my Acorn Archimedes A310 recently died and I am now looking for a suitable alternative. At present I have it working on a 15" flat screen via the monochrome video output (definitely not desirable). I am not the most clued up person in the world when it comes to Acorn computers and was just wondering what my cheapest option might be. Looking for full colour and smallest possible display foot print. I would like if possible to avoid another CRT display. From my own research, the only real option I found was to buy an A310 -> VGA adapter (about £60 on eBay). I just wanted to know whether I might have missed a trick. As the machine has a VIDC enhancement, is it possible to just buy an RGB 9 pin -> VGA cable and to create a custom working mode?

In my experience, a standard 9pin-15pin VGA adaptor (should be less than a pound really) is sufficient to connect any old analogue VGA LCD to an A310, if it is not really picky about "this is not true VGA timing!". A VIDC enhancer might be nice, but it is not necessary if you don't need 800x600 (and on an ARM2 machine with 8 MHz RAM, the high res modes are quite slow anyway). Just remember to configure the monitortype to SuperVGA (is it type 4? I always forget). There is also an add-on module available that might help with making the screen modes look less letterboxed and let you run typical games without too much problems - it is called "LCDGameModes", see here: https://www.retro-kit.co.uk/LCDGameModes/

If you want a new, widely compatible LCD which even supports the good old 15kHz screen modes (aka "PAL"), look at the BenQ BL912. Not cheap, but the most compatible "modern LCD" I know of. Unfortunately its native res is 5:4 (1280x1024), but since none of the old modes will be pixel-perfect anyway and the scaling is quite good, you can get used to it.

Have fun
hubersn

[oo00Kman00oo]

Thank you so much, that's some excellent advice. I got the 9pin-15pin cable today and gave it a try but nothing, no signal being received by the monitor. I can still see a picture via the monochrome out which is helpful. Tried changing WIMPMODE a number of times but didn't achieve anything other than messing up the monochrome video out. Managed to get that back with a reboot DEL. I did try reboot and 3 which I thought set VGA mode but there were no changes at all. Will give reboot and 4 a try later. It just feels like a sync issue. I just wondered if there were any specific modes I should put my A310 into to see the display.

[oo00Kman00oo]

I am starting to wonder now if I don't actually have a VIDC enhancer. I could have sworn there was one in the machine. Would they always be installed just behind the RGB out above the main board?

[steve3000]

Yes, just behind the RGB socket, Paulv's website shows how his modern VIDC fits in an A310, here: https://www.retro-kit.co.uk/Ultra-VIDC-Enhancer/

Enhancers from back in the day plug in the same location, but look older

But even without an enhancer you can usual get some sort of picture, providing your sync is configured correctly (on the A310 if you have no enhancer fitted you'll have to modify a PCB tracked link to provide separate syncs, and be prepared for odd colours as the A310 suffers the sync-on-green issue without an enhancer). See Paulv's ultraVIDC installation manual at the link above for useful information on this.

Also, you say you bought a 9pin to 15pin cable - just a warning that some of these available on popular auction sites do not work on the Archimedes. I bought one a few years back and the HSync and VSync pins were wired incorrectly for the Archi 9pin socket. I'm sure there's an Acorn tech note which details the correct wiring, but I don't have a link to this at the moment.

[DutchAcorn]

The tech note is here: https://www.retrocomputers.online/wp-co ... nitors.pdf

This site is also very helpful: http://www.riscos.org/legacy/monitors.html

[DutchAcorn]

The trouble with connecting a VGA monitor directly to the analogue RGB port of an A310 without a VIDC enhancer is that you are stuck with the VGA modes. RiscOS applications are fine but most games will not run.

So you either need a VIDC enhancer or 15KHz->VGA conversion hardware if you want to play games.

See here for a short discussion on the GBS-8200 converter: viewtopic.php?f=16&t=12754&p=167627#p167627

*Edited to add a link for the GBS-8200.

[oo00Kman00oo]

Many thanks for all the replies. It definitely looks like I don't have a VIDC enhancer. I think my machines has a MEMC1 upgrade in addition to a riser panel with lot's of memory chips on. I think the latter was so it could run RISCOS 3.1 if I recall correctly. I have dropped the chap at Retro Kit an email this evening to see whether he still makes or has any of the Ultra VIDC enhancers. Alternately I see that CJE might still sell them.

[oo00Kman00oo]

I have checked out various images from the internet and can confirm that my machine doesn't have a VIDC enhancer

My specs are:

Acorn Archimedes A310 mainboard with A420 info panel on front (no idea why, guess the original was lost)
IFEL 4MB upgrade
VLSI VL86C020 - ARM3 upgrade
RISC OS 3 ROM set in an IFEL carrier board
Watford Electronics 4 way backplane
ICS ideA IDE interface
IDE-SD adapter with 1gb SD card (using 500mb partition) (original HD is broken)
Working floppy drive

The only thing I am stuck on is whether or not it has the MEMC1/MEMC1a chip. I have a attached a photo but it doesn't seem to match with any MEMC chip photographs I can find online. Anyone know which version this is? Thanks.

[danielj]

Without the VIDC enhancer, the BL912 will give you all the PAL screen modes quite happily. Not sure what'll happen trying it with the "pseudo VGA" modes without an enhancer, but on an arc of that generation, you weren't really looking at VGA. You could drop PaulV a note and see if he's got any enhancers going at the moment?

edit: that chip's the I/O chip. The MEMC should say ANNA on it if it's the first version. See here: https://www.retro-kit.co.uk/page.cfm/co ... 0-RISCOS2/

d.

[oo00Kman00oo]

OK thanks, I think I found the correct one now, just by the floppy drive. Updated photo included. It doesn't look to be the original chip, but it also doesn't seem to match the MEMC1A on the link you sent danielj. Could it be a MEMC1 instead? - I dropped PaulV a message last night, so will wait and see whether he has any Ultra-VIDC's available at present. Thanks.

[DutchAcorn]

If you have the ARM3 upgrade, you will have the MEMC1a installed. The MEMC upgrade is needed for the ARM3 upgrade.

[oo00Kman00oo]

I assumed after looking at the datasheets for the VLSI VL86C020 chip that this is my ARM3 upgrade. Again it's just behind the floppy disk drive.

[DutchAcorn]

I assumed after looking at the datasheets for the VLSI VL86C020 chip that this is my ARM3 upgrade. Again it's just behind the floppy disk drive.

Yes, that’s an ARM3.

[hubersn]

It just feels like a sync issue. I just wondered if there were any specific modes I should put my A310 into to see the display.

Remember to configure your machine for seperate sync - not sure how that is done on A310, but the A3000 needed that to be compatible with later monitors (even the NEC MultiSync 3D was "later" in those times of the past). You also need to do a configure sync 0 (or CMOS reset with T hold). Configure monitortype to SVGA and put mode/wimpmode to 27. This is pseudo VGA 640x480@60Hz, but works OK for most screens.

If it doesn't work with your screen, I would suggest finding a more tolerant screen instead of trying to tweak the hardware with a VIDC Enhancer. A VIDC Enhancer is great to make 800x600 possible, but it won't help to make game XY compatible with your picky screen if it uses a custom mode.

Have fun
hubersn

[trixster]

If I remember correctly on my A420/1 I had to set LK1 to north, LK2 to closed and *configure monitortype 3. My LCD monitor (a dell 2001fp) will then display the desktop in mode 27 640x480x16

This page talks about the A300 series:

http://www.riscos.org/legacy/monitors.html

[alienkidmj12]

where do i buy vidc enhancer for a3000

[SmellyGeekBoy]

Any advice on using an A305 with a slightly later AKF50 monitor? I'm using a cheapo eBay 9-pin to 15-pin adapter. First time I booted I got a signal that seemed like the sync was broken. I tried a few reboots holding down various number pad keys and now all I get is a blank screen!

I'm not against the idea of buying and soldering a VIDC enhancer if it will fix my issue but I just thought I'd check if there's anything obvious I should be doing first. I even checked the (printed) manual but to no avail!

Edit: It has a RiscOS 3 upgrade, if that changes anything...

[SmellyGeekBoy]

OK, I got the AKF50 working with my A305. I couldn't find this documented anywhere so the process is as follows:

• Connect another monitor to the mono composite output (I used a PVM-type CRT monitor)

• Hold down "Delete" while switching power on

• You should have a usable picture on the mono output

• Use this to run !Configure and then go into the "Screen" option

• Uncheck "Interlace"

• Uncheck "Automatic Mode Selection" and change the mode to 20. The screens will flicker every time you change mode.

...Voila! A lovely crisp colour output on your AKF50.

(I assume this works on the AKF60 and AKF70 series too as they're also multisync. Will give it a try with my AKF65 when I get a moment...)