From: tomc@siesoft.co.uk (Tom Crossland) Subject: Multi[Sync/Scan] Monitors (Summary of Responses) Date: 5 Oct 92 18:23:16 GMT Thanks to all who replied to my original posting. Here is a summary of responses... >Can anyone recommend some good multisync (multiscan, etc) monitor to use >on an Archimedes? I don't want to spend TOO much on it, just something >that looks good in hi-res modes. ----- From: Andrew.Stevens@prg.oxford.ac.uk ----------------------------------- the Panasonic multi-sync I bought from Watford a year and a bit back was inexpensive and just about perfectly matched to the Arc. It is still working flawlessly too... (albeit attached to a 486 PC these days). The Panasonic was 240 or 260 pounds + VAT around 18 months ago. ----- From: gta@st-and.ac.uk (Graham Allan) ----------------------------------- I have an AOC multiscan monitor - I forget the model number - which I have recommended in the past (and still would). It's not as solidly built as Taxans etc, but at about UK#235 its about half the price. It will display the standard 50Hz screen modes as well as those extra high-resolution ones produced by a VIDC enhancer. Picture quality is fine. I got my monitor from College Computers. The first one died after 4 days but the replacement is fine. I can't say much about the failure of the first one, these things happen... (their quality control may be not as good as more expensive makes, but any fault due to that would occur during the first 2-3 weeks anyway). ----- From: chughes@maths.tcd.ie ---------------------------------------------- I'm waiting for the arrival of an Eizo 9060s I ordered a week ago from Watford, having used a Philips CM8833 (same as Acorn's standard medium res Arc monitor) for the past five years; they charge #389+VAT & carriage (carriage to Ireland is #12, so not a big cost) for it; if that's within your price bracket I'll let you know what I think when it arrives.. >From what I hear, the Taxan (795?) has good colour reproduction, but the Eizo has a sharper picture and so is better if you're more into text than art.. ----- From: Jon Thackray ------------------------------------ I've just bought an Eizo 9060S, which *wasn't cheap*, but before doing so, I was looking at cheap multisyncs. The short answer is, there aren't any. (good ones, that is...) The cheapest I found was an AOC CM326, at #249+VAT from most PC dealers, but when I came to buy it, found it was discontinued. Besides, that couldn't even do 1024 x 768 non-interlaced (a common test for PC SVGA monitors), so in the end, I decided to lash out for this one - and worth it - I would say. If it saves me eye-strain in the long run, it's worth it - mine goes up to 90Hz, although most of my Arc modes aren't defined past 70Hz. I haven't had any trouble switching modes, all the knobs are on the front underside, as rotary switches, the manual leaves a bit to be desired, and the model has been around for a couple of years at least, but quite a few people have them. ------------------------------------------------------------------------------- From: bdb@cl.cam.ac.uk (Brian Brunswick) Subject: Re: multi-sync monitors Date: 1 Mar 91 10:40:26 GMT >I am about to buy an A540 + multisync monitor ... >The monitor I am specifically interested in is the Taxan 795, ... Ok, I'll jump to this one, since I posted about the Taxan a while back. There are basically two parameters to a mode that affect whether it can be displayed by a given monitor - the horizontal sync rate and the frame rate. For a normal TV, the hrate is 15KHz, and the frame rate 50Hz - so thats 300 lines (These figures are approximate) The standard multisync modes like 20 double the hrate to 30KHz, and get 600 lines. The trouble with the 795 (which is otherwise very nice) is that it can only handle horiz rates of 30-57KHz, so any standard mode won't work, though the multisync ones will. However, it is possible to modify the format of existing modes to bring them into this range. This is done by loading a patch module - So if its a game that runs by some boot sequence that you can't get at, you're well Zogged, as certain people in Cambridge might say. There are two other issues here as well. Firstly, a standard Archi can only chuck pixels out at 24MHz, and with 8MhZ memory has a total memory bandwidth of about 25Meg/s. So not all existing modes can have their line rates increased sufficiently. There are hardware add ons which increase the max pixel rate to 36MHz, but you are still stuck. With a 540, I understand (check me on this) that it has such a mod built in, and also has 12MHz memory. So these figures go up, and its easier to fix things. Secondly, a lot of games take their timing from the fram rate. If your replacement mode uses a different frame rate, games will (attempt, and with an 540/ARM3 do quite well usually) to run fast. However, the frame rate can easily be reduced by leaving large gaps above and below the data, and adjusting the monitor to expand it vertically - make sure you get a version of the patch module with this ability. Basically, for the Taxan795, make sure you see it running before you buy, switch modes around, find out how to adjust it, and work out whether you personally can stand the irritation. But its a lovely picture - I recommend it. Brian.Brunswick@uk.ac.cam.cl Disclaimer. Short sig rules! From: osmith@acorn.co.uk (Owen Smith) Subject: Re: Monitor for both Arc and VGA PC Date: 22 Nov 91 13:21:37 GMT >Which of the various multisync types would be the best bet, based on >people's experience? I want one which gives minimal hassle - ie : there >shouldn't be problems with screen centring etc.... I would strongly recommend the Eizo 9060S, which I have been using for a year now. Screen centering is fine on all standard modes, and most of the AtomWide and CC extra modes. Some of the extra modes need moving a bit, but the controls on the Eizo 9060S are flexible and more to the point the monitor does what you tell it rather than trying to get clever and failing (many Taxan and NEC monitors suffer from this). The important thing is to match the monitor to the Archimedes. All the monitors are designed to work with PCs, so that PC should not be a problem. The other thing to watch for is monitors which are not truly multisync. The cheaper monitors have simple circuitry which says "is this signal CGA, EGA or VGA?" and set themselves up appropriately. These monitors have problems on the Archimedes, because some of the modes do not fit any of the PC standards. You want a truly flexible monitor which just displays whatever is sent to it. (The Eizo 9060S is of this type.) I would recommend against the Taxan 795 - it won't run slow enough for the standard Archimedes modes so you have to use fiddled versions of the modes with lettering boxing and stuff, and also games which time on the VSYNC tend to run fast due to refreshing the screen faster to get the pixel rate up high enough for the 795 to work. Owen. The views expressed are my own and are not necessarily those of Acorn. From: gta@st-andrews.ac.uk (Graham Allan) Subject: Re: Multisync monitors Date: 9 May 92 14:13:32 GMT I eventually managed to find a *cheap* multisync which works in all the Archimedes screen modes. This is made by AOC, model number CM-326. I'd never heard of the name, but looking round the physics department here noticed a few assorted AOC monitors which looked okay, and as if they'd lasted 3 or 4 years. The CM-326 costs around #240; I got mine from College Computers but lots of PC dealers probably have them. The AOC will scan the 'standard' modes 0-16 & 24, and the multiscan and VGA modes, plus any custom modes defined with a VIDC enhancer. I would imagine it's designed to go up to the SVGA spec. Resolution is up to 1024x768 with 0.28" dot pitch (standard Acorn is 0.42", to compare). The picture is reasonably sharp and clear; not quite up to a Taxan 795 - but it is about half the price. The tube itself is made by Panasonic, so is probably not bad. Only disadvantage is having to recentre the display when changing between multiscan / custom / standard modes - but that's a common problem. Only the horizontal centering needs tweaking so its not a big deal. The only other operational difference from a Taxan or Eizo is the amount of shielding (there isn't any) - the microwave in the kitchen is the other side of the wall from the monitor, and when it's running, the picture goes all wavy (as if introducing a 'dream' sequence in a bad 60's movie)! There is a word of warning, though - I suspect a lot of the difference in cost between cheap and expensive monitors is due to the amount of quality control at the factory. The first sample I got died after 3 days. The replacement one I have now has lasted a month so will probably be okay - if a piece of equipment like this can last for 10 days continuous running, then its likely to last for a few years; any badly out of spec component will generally fail in the first few days. Graham Allan Physics Dept., University of St. Andrews From: torq@hal.gnu.ai.mit.edu (Andy Mell) Date: 10 May 92 01:47:14 GMT >Is there a multisync monitor that works well with the Archimedes >in all modes? What is it? *THE* monitor for the archimedes has to be the Eizo 9060S, it displays all modes fine, it can scan analog between 15.5kHz and 38.5kHz, you do have to adjust it for SVGA modes (per 540,260,5000) but all normal and msync modes work fine. The picture is bright and clear. Easy access to the controls. BTW: If you are thinking of buying an Eizo from a PC dealer, dont, get it from a reputable archimedes dealer as Eizo set up the monitors internals specifically for the archimedes, they are a different model to the normal PC Eizos. Andy (Yes you guessed - I have an Eizo, and its a hell of a lot better than any other monitor that I have seen on the Arc) From: ee88jmf@brunel.ac.uk (J M Fielder) Subject: Re: VGA monitors for the Arc Date: 28 Apr 92 10:04:03 GMT >Since you can buy PC VGA monitors which now seem to scan frequencies upto >SVGA fairly cheaply, is it possible to connect one of these monitors to an Arc? >If anyone has got a PC VGA monitor on their Arc, what model is it, how good is >it, and what pin connections do you have to make to the connector on it. Seeing as this is coming up more and more, how about adding the below to the FAQ? Question: Can PC VGA Monitors be added to an Archimedes? Answer: It depends on what monitor you have, and what Archimedes you have. There are two main types of PC VGA monitors out there... 1) Fixed Frequency These monitors will only display video signals with certain line and refresh rates. They will typically only display CGA / EGA / VGA modes. 2) Mutil Frequency These monitors will display any video signal within a certain range, typically 30-50Khz line rate and 50-80Hz refresh rate. Type 1 almost always require seperate syncs as the monitor uses the polarity of the syncs (mainly positive going negative or mainly negative going positive) to determin what the line and refresh rate should be. Type 2 vary. Some require seperate syncs (vertical and horizontal) and others will work with composite syncs (vertical and horizontal EOR together). As PC monitors typically start at a line rate of 30Khz compared to the TV broadcast modes (mode 12 etc.) that have a line rate of 15Khz, VIDC has to do more work to obtain a 30Khz line rate. This means that you computer will slow down silghtly if you use a 30Khz+ line rate monitor. Now, depending on what type of Archimedes you have depends on what type of monitor you can use. A540 / A5000 Has software control over the polarity of the syncs and what frequency VIDC is clocked at. The A540 with RiscOS 2 can only use modes 26-28 (640x480) [I can't rember if an A540 has a mode 31, help?]. However, by changing links and a *configure option, you can get the computer to generate seperate syncs with no problem. The A5000 with RiscOS 3 can do even better. If you tell the computer that you have a VGA monitor it will re-map all of the 15Khz line rate modes upto 30KHz line rate. This means that you can play your games that require mode 12 / 13. However, as a PC monitor is designed to display 320 lines minimum then you will get a 'letterbox' effect as mode 12 has only 256 lines.i Both the A540 / A5000 have a 24Mhz, 25.175Mhz and 36Mhz crystals to drive VIDC with. The 25.175Mhz crystal is needed to obtain the correct video rates for PC monitors displaying 640x480 screens. The 36Mhz crystal is used to obtain higher resolution modes, like 800x600x16 colours. A3000 This can generate seperate syncs but requires links to be set to determin the polarity. It has only a 24Mhz crystal and can therefore only drive 'forgiving' monitors correctly that don't mind the 640x480 video mode timings being slightly incorect. In order to obtain proper timings, and software control of the sync polarity, you will need a Watford Electronics VGA VIDC Enhancer for the A3000 (See below) A400 series. The situation gets more complex. Due to an 'error' in the PCB / circuit diagram, the A400 series cannot generate seperate syncs satisfactorly. The video signal loses the green component when seperate syncs is selected. As standard, there is no polarity control over the syncs. In common with the A3000, there is only a 24Mhz crystal. If the PC monitor can handle composite syncs then the monitor can be used in 640x480 mode only. A300 series. Most, if not all, of the A300 series had the circuit board hardwired into composite mode continously. There is only a 24Mhz crystal, and only composite PC VGA monitors can be used. Concusion: Apart from the A5000, no computer as standard can drive either a fixed frequency or multi-frequency PC monitor in all of the Archimedes modes satisfactorly (how do you spell that?) [Note, the below is probably an advert, and I make no mention of any other VIDC enhancer, as there is no other that can generate composite syncs, and has the 25.175Mhz crystal needed for correct video timings] The Watford Electronics VGA VIDC Enhancer Available in two versions. A300 / A400 series If you have an A300 series computer, then your motherboard needs some surgury (?) on it to create a header for the expansion. Any 'competent' person can do this, or any local dealer will probably do it for #10 or so...... The VIDC Enhancer provides three functions. a) To split up the composite sync generated by the archimedes (so the video isn't disturbed) into horizontal and vertical seperate syncs. b) To provide software control over the sync polarity c) To provided software control over VIDC's clock rate. There is a 25.175Mhz and 36Mhz crystal on the VIDC enhancer. Supplied with the VIDC enhancer is some new modules that re-map ALL pratical modes (modes 0-15, 7 included) to the new higher line rate. These modes have been 'pre-optimised' for various VGA monitors already. Also supplied is a mode defining utility with alows software control over the clock rates, sync polarities, and will make a mode that matches defined line and frame rate for fixed frequency monitors. Supplied also is a 'tweaking' utility. Some monitors will display some modes 'off centre', with the result that you have to fiddle with the controls. With the WE software, leave the controls in a centeral position, and the screen can be 'moved around' the monitor until it is centeral. A3000 version Exactly the same as above, except the seperate syncs are generated by the Archimedes rather than the VIDC enhancer. There is no WE software only for the A540 computer to re-map all of the modes. Hope that helps.......... Joust