Amiga.org

Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: raoulduke on April 09, 2016, 06:34:27 AM

Title: How to Use an A2320
Post by: raoulduke on April 09, 2016, 06:34:27 AM
Hey, I'm very new to Amiga and there are aspects of it I find confusing.  After reading the manual I think, but am not sure, that an A2320 card if working should just output to a monitor.  Mine does not (with the bypass switch in either direction).  I haven't bothered with fine tuning but is it broken or am I missing something (a la drivers etc.)

I haven't tried it with WB fully booted, so if it does need drivers it's possible/probable they're installed.

[I'm really concerned about trying to reformat and reinstall because the machine won't seem to boot from a floppy with my Great Valley SCSI card for some reason (or bc of the memory on it, not sure).]
Title: Re: How to Use an A2320
Post by: Effy on April 09, 2016, 10:00:01 AM
Think the A2320 was limited to 16 colours only, so it may appear faulty when you plug it into an A4000 with 256 colours enabled ... doesn't it even show screen when you boot with two mouse buttons down ???
Title: Re: How to Use an A2320
Post by: guest11527 on April 09, 2016, 10:00:35 AM
Quote from: raoulduke;806965
Hey, I'm very new to Amiga and there are aspects of it I find confusing.  After reading the manual I think, but am not sure, that an A2320 card if working should just output to a monitor.
The A2320 does not require any software installation. As soon as it is installed in the RGB slot (you put it there, right? It does not go into the Zorro slots) it should give you a picture. Probably not ideal, but at least a 31kHz signal your average VGA monitor should be able to display.

Is the cart really fit tightly into the slot? Try to push it down firmly.

Just one additional note: While the card doubles the horizontal frequency from 15kHz to 31kHz, it does not change the vertical scan frequency. In specific, the average VGA monitor will not sync down to 50Hz (PAL), so you'd probably want to change that to NTSC (60Hz) in the early startup menu. Hold down both mouse buttons while turning the machine on, press space.  Greetings, Thomas
Title: Re: How to Use an A2320
Post by: raoulduke on April 09, 2016, 07:05:13 PM
Forgetting the port, which idk how to debug with no obvious output, will the card working/not working affect my video memory count?  The A2320 has 384k? How much should show up normally on an A2000 Rev. 4.4?
Title: Re: How to Use an A2320
Post by: midway on April 09, 2016, 07:39:57 PM
The A2320 is supposed to be used with ECS or OCS Amigas only.
It displays all of these modes normally. That's including HAM interlaced (4096 colors)
 Its not a graphics card, doesn't matter how much buffer it has, it wont show up. What you see is Chip Ram. 512 KB for your Amiga 2000.
Title: Re: How to Use an A2320
Post by: Oldsmobile_Mike on April 09, 2016, 08:23:50 PM
Check in early startup, or maybe with a program like Scout or SysInfo, is the card detected?  (not sure if video slot is scanned by those utilities)
Title: Re: How to Use an A2320
Post by: Matt_H on April 09, 2016, 10:42:48 PM
@ Oldsmobile_Mike

I don't believe the video slot contents can be detected by anything.


@ raoulduke

To expand upon what others have said, the 2320 is intended for the A2000 and no drivers are required - plug it in and it should work. If you have a PAL (European) machine and you are using a modern LCD monitor, you may have problems. Most LCDs can only sync to 56Hz vertical refresh and PAL is 50Hz vertical refresh. Some LCDs can handle 50Hz - try to find one of those or an older CRT display to test.

But to back up a step, can you confirm that the Amiga is working (read: booting up) at all? There's a black and white composite video port on the A2000, which is handy for diagnosing basic signs of life.
Title: Re: How to Use an A2320
Post by: raoulduke on April 10, 2016, 12:59:40 AM
Yeah the machine works great... after I destroyed and rebuilt it.  I'm using a 520 adapter with the video out to a large lcd television; the mono output also works.  I think I've run down the manual for my monitor which says that it'll work at 31.5khz with 640x480.  The monitor itself reads a signal (but stays on standby) but there's no actual display.  The card is in the proper socket.  I took it out and put it back in but I haven't done much else including popping the ROM.  I'm replacing the HD at the moment.
Title: Re: How to Use an A2320
Post by: raoulduke on April 10, 2016, 03:19:17 AM
So the skinny is this: On my Dell 1704FPS monitor in analog mode, with the bypass away from the fan, which I think is off, the monitor oscillates between green power light, meaning either power or signal - not sure, and orange power light standby mode.  When it goes to green there's backlighting but no picture.  The same test on my large LCD television shows no signal.  

I thought I'd read I was looking for one that supports 31.5khz, but so should I be looking for an old (like mid-90s branded) CRT or a just older-than-mine LCD...?  I'd really rather not use a CRT; but if I have to pay $5 to definitively test the card I will.

Whether or not the utilities you suggested would work I haven't figured out how to transfer files and it just occurred to me that when GVP Utilities accidentally wiped my Zip Drive backup I lost PC Utils; so I'll have to grab it off the original HD again.
Title: Re: How to Use an A2320
Post by: raoulduke on April 10, 2016, 05:49:32 AM
Actually there is a test disk: http://amiga.resource.cx/install/A2320-12.dms  (*Actually it may just be the flicker test disk...)

And actually instead of the $5 for a CRT; maybe I'll just get the Amiga display to VGA cable.  Is there some reason that would be inferior?
Title: Re: How to Use an A2320
Post by: Oldsmobile_Mike on April 10, 2016, 01:16:04 PM
Quote from: raoulduke;806987
And actually instead of the $5 for a CRT; maybe I'll just get the Amiga display to VGA cable.  Is there some reason that would be inferior?


If you're talking about just converting the 23-pin output to a 15-pin (VGA style connector), this isn't the same as scan doubling to 31Khz. It will only be 15Khz. Very few modern monitors will support it (and only a few screenmodes).

If you want to display native Amiga output on a modern monitor, why not just get an Indivision?
Title: Re: How to Use an A2320
Post by: guest11527 on April 10, 2016, 01:24:54 PM
Quote from: Oldsmobile_Mike;806977
Check in early startup, or maybe with a program like Scout or SysInfo, is the card detected?  

No chance. The video port does not participate in the autoconfig detection, and there is also no hardware logic that allows software to check whether a card is plugged into the video port or not.

The most likely problem of the OP is that the monitor does not synchronize to the frequency of the scan doubler. It is a 31kHz signal, but possibly a 50Hz vertical scan frequency the monitor does not pick up. It is neither 100% VGA compliant (i.e. even the scan-doubled NTSC signal of a 640x200 - then 640x400 - frame does not exactly conform to VGA).
Title: Re: How to Use an A2320
Post by: midway on April 10, 2016, 04:07:18 PM
I had an issue once with an A2320 and a TFT. I needed to use the calibration device forgot the name of it in English sorry (a little part at the back of the card were you can use a (grounded/shielded) screwdriver turning clock or counterclockwise with the Amiga running and open (so be careful) and a CRT first to see the picture staying in sync. I had to borrow one from a friend, after that it worked fine with my TFT
Title: Re: How to Use an A2320
Post by: Matt_H on April 10, 2016, 05:58:48 PM
@ raoulduke

In the old days, the issue for Amigas was finding a monitor capable of displaying 15KHz horizontal, or scandoubling the Amiga's display to 31KHz horizontal. Nowadays the issue is finding a monitor capable of displaying 50Hz vertical. Every display can handle 31KHz horizontal now, but 50Hz vertical - common in the CRT days - is unusual.

Many of us have had luck with a variety of Dell displays, mostly those that also have HDMI ports. There are a few threads around the forum about this. I'm using a Dell ST2320L, a U2410, and a U2412M successfully at 50Hz vertical.

The Indivision ECS is a more modern internal scandoubler that plugs into a chip socket (instead of the video slot) and has some extra logic to optionally bump 50Hz vertical output up to something that just about any LCD can display.
Title: Re: How to Use an A2320
Post by: raoulduke on April 11, 2016, 12:34:10 AM
So I got a Viewsonic VA1912wb.  It's not a great monitor but it also detects no signal; and purportedly supports 50hz - someone (please) feel free to contradict me there.  It's starting to look like the problem is with the card itself.
Title: Re: How to Use an A2320
Post by: paul1981 on April 11, 2016, 12:50:14 AM
Quote from: raoulduke;807018
So I got a Viewsonic VA1912wb.  It's not a great monitor but it also detects no signal; and purportedly supports 50hz - someone (please) feel free to contradict me there.  It's starting to look like the problem is with the card itself.


Have you tried 60Hz yet (NTSC) ?
Title: Re: How to Use an A2320
Post by: raoulduke on April 11, 2016, 12:56:49 AM
You need to treat me like a total noob.  Do I need to move stuff from Monitor Store to Monitor?  How do I control the frame rate?  Do I need to adjust the display mode[/resolution; is there a difference?] before I get a picture on the monitor?  If it just involves adjusting resolutions on the Amiga, then the only options I have are NTSC hired and interlace, and nothing works.  I've gone through every 60/70 mode and neither works.

It looks like I was misled, though, the Viewsonic looks like it cannot do 50hz.  Both monitors seem to have settings that variably use 60hz (but it doesn't work on either).  Clearly my 1704FPT is actually getting some type of signal.  So I guess I'll look for another screen tomorrow.
Title: Re: How to Use an A2320
Post by: guest11527 on April 11, 2016, 07:27:07 AM
Quote from: raoulduke;807022
You need to treat me like a total noob.
Well, essentially, based on your questions... you know, what else would you expect....  
Quote from: raoulduke;807022
Do I need to move stuff from Monitor Store to Monitor?  
Once again: No.  
Quote from: raoulduke;807022
How do I control the frame rate?  
You don't. PAL is 50Hz, NTSC is 60Hz. There is no other way of control. That are also the only modes the 2320 can handle.  
Quote from: raoulduke;807022
Do I need to adjust the display mode[/resolution; is there a difference?]
No. Pick a NTSC screen. Make sure the 2320 is *on* (switch in the back). Make sure it is properly seated. Make sure you connect to the right plug (yes, it is the VGA plug that comes out of the 2320), with the right cable (a standard PC VGA cable).  
Quote from: raoulduke;807022
before I get a picture on the monitor?  If it just involves adjusting resolutions on the Amiga, then the only options I have are NTSC hired and interlace, and nothing works.  
If you've checked all the points above I mentioned, and you've tested on another monitor, then the 2320 is just broken. Happens with old hardware.
Title: Re: How to Use an A2320
Post by: raoulduke on April 11, 2016, 08:55:02 AM
Thanks.  Wait...  I only get two options - both NTSC options - in the Screen Mode Pref.  Is that because it's detecting the A520 but not a monitor?  In other words, if it detects a valid VGA monitor (and also, of course, the A2320) then other options will pop up on the Amiga?

I assume there's no problem with simultaneously outputting via the A520 and the A2320 (?).  I just tried all my monitors with just the vga cable and then checked with mono to see if there were any other options, which there were not.  But I don't really have a good conception of how this is supposed to work other than turn it on and it works...

So to return to the issue, I'm still looking for a VGA monitor that can support 50hz vertical?  That's not really an NTSC or PAL thing.
Title: Re: How to Use an A2320
Post by: guest11527 on April 11, 2016, 09:39:43 AM
Quote from: raoulduke;807039
Thanks.  Wait...  I only get NTSC; is that a model issue and not a mode issue (I'm in the US)?  And if NTSC is only 60hz and my monitors can do 60hz... that doesn't seem great.
NTSC = 60Hz is ok for most monitors. I say "most" because the output generated by the 2320 is scan-doubled 60Hz NTSC, which is "almost, but not quite" VGA. Hence, if your monitor is really picky, it might not be able to synchronize to this signal. Actually, I have never seen this happening, but in principle, it might be possible if the monitor requires the precise VGA timing.

There is no need to try the PAL modes, and whether you pick interlace or hi-res makes no difference. The output signal timing is exactly the same for both.
Quote from: raoulduke;807039
So other than the specific models Matt_H listed, what should I be looking for?  
Only what I already said. Make sure the monitor is connected to the right output (that of the 2320) with the right cable (VGA), the input of the monitor selects the VGA input (not HDMI, not DVI, not DP, not SCART), and the 2320 is turned *on* (note the switch on the back).

If *that* doesn't give you a picture, then either your monitor doesn't like the signal (unlikely, but possible) or the 2320 is just broken (also happens).  
Quote from: raoulduke;807039
And I can get a CRT; I just don't see that as a great solution.  And will any of this be a problem for the Amiga to VGA cable converter (just a cable)?

Look, if you believe you need an Amiga to VGA cable converter, you did not read responses properly. Once again: Do *NOT* connect the monitor to the "MONITOR" output of the Amiga. This is the *wrong* output. Connect it to the VGA output on the back of the 2320. You do not need a VGA cable converter for that. The output of the 2320 is a standard VGA plug, not a 25-pin Amiga MONITOR plug. You need a standard, off-the shelve, VGA cable. There is no converter needed, neither for the monitor, nor for the 2320. It is a standard cable you can pick up for a few bucks in the next electronics store.

Leave the MONITOR output of the Amiga open. Do not connect anything to this output anymore. You don't need the MONITOR output. Use the VGA output of the 2320. There is only one plug in the back of the 2320, and that's the right plug for the VGA cable. Attach it with the little screws on the back, fit the cart firmly into the computer. That's all what is needed.

If your TV or your monitor does not have a VGA input, you cannot connect it to the 2320. Do not try to fit a SCART connector by adapters to the 2320, this wouldn't work. A standard VGA cable, one end in the 2320, the other in the monitor, will do. Nothing else needed.
Title: Re: How to Use an A2320
Post by: raoulduke on April 11, 2016, 09:52:39 AM
I finished editing way before you posted...  sorry.  But thank you for the info

[and lol.  I got the Amiga to VGA cable because this doesn't seem to be working.  It'd be pretty nice to be able to use my current second monitor that's on my desk rather than a gigantic television.  I also suspect the resolution is likely better?  I think we may be speaking past each other, I'll grant you that.  But I'm not sure it's because I'm not reading the responses.]

Okay it's very clear I misled you by asking you to treat me as a noob and that you didn't read my context there or my follow-ups about it.  I am explaining to you that I am not familiar with the Amiga operating system.  I got very, very angry writing the follow-up.  So suffice it to say either I have failed to include any relevant information with respect to how I've been testing this system, or you have not read my posts.  I will post only to confirm success.  Thank you again for the information.

Maybe it was me.  The A520 and the mono output are both via composite...  It's nice to see the screen, so I've been using those.  I was curious if using those while testing the A2320 might interfere with the A2320.  It doesn't matter, none of the 3 VGA monitors I've tested it on work.
Title: Re: How to Use an A2320
Post by: paul1981 on April 11, 2016, 01:04:45 PM
Your Amiga won't mind or even know that you're using the A520 and/or the A2320 output or even the mono composite output.

As Mike said earlier, if you'd like the best picture on a VGA monitor you'd be best to purchase an IndivisionECS.

http://amigakit.leamancomputing.com/catalog/product_info.php?products_id=918 (http://amigakit.leamancomputing.com/catalog/product_info.php?products_id=918)

If you want a new monitor, then you might want to read this thread from start to end:

http://www.amibay.com/showthread.php?72457-BenQ-BL702A-perfect-monitor-for-amigas (http://www.amibay.com/showthread.php?72457-BenQ-BL702A-perfect-monitor-for-amigas)

BenQ BL702A does work with the Amiga series without anything extra, but you will need a buffered VGA converter adapter for your Amiga video output port on 'big box' Amiga's, as yours is an A2000. Read the last page regarding the Dell monitor... it gives the best picture by far but it doesn't remember screen position!

I'd sway towards an Indivision. But, how about getting a 1084S or something for the authentic experience?
Title: Re: How to Use an A2320
Post by: Matt_H on April 11, 2016, 07:49:55 PM
Also have a look at the 2320 manual: http://amiga.resource.cx/exp/a2320
Title: Re: How to Use an A2320
Post by: utri007 on April 11, 2016, 08:36:27 PM
If you are located to Europa, you could also use bog cheap SCART cable to connect it to your LCD-TV. Most of them works also as a flicker fixer.
Title: Re: How to Use an A2320
Post by: raoulduke on April 12, 2016, 08:14:25 AM
Matt_H, thanks.  I had browsed through the manual but I read it in more detail and tried random stuff like changing the jumper to openloop for the same tests I'd done with it on closedloop as its default; checked the J300 jumper on the 2000's motherboard.  Utri007, I've tired it on like 6/7 monitors one of which was a TV, but I'm in the US.

Thanks Paul; the manual also mentions that mono/Amiga display port connections don't interfere.  But i had missed that at first.  I've gotten a bunch of monitors at this point, the last of which - a Dell E773c has a vertical frequency scanning range that starts at 50hz.  Unless I'm misunderstanding the vertical frequency scanning range thing on the E773c (like unless that doesn't mean it supports 50hz, but I think it means that it does) I think that's a definitive failure with the card.  The E773c senses that its VGA cable is connected but otherwise gets no signal.

But I also think Thomas Richter has a point; I think I probably wouldn't have gotten no indication of a signal even if the monitor didn't support 50hz (maybe I'm wrong); but also monitors that at least claim to support a 50hz vertical scanning frequency are not necessarily easy to find (the first CRT I bought today only went down to 55).  Pity; but ... lucky I ordered that Amiga to VGA adapter cable...  Thanks for your help guys.
Title: Re: How to Use an A2320
Post by: Matt_H on April 12, 2016, 11:42:06 PM
Unfortunately, I don't think the Amiga-to-VGA adapter is going to solve your problems unless it's the so-called Commodore silverbox adapter (http://www.bigbookofamigahardware.com/bboah/product.aspx?id=733) (or compatible - there are a few) and your monitor is capable of 15KHz horizontal. The straight-through 23-pin to 15-pin converters don't work on A2000s (or at least, not on mine) and will prevent the machine from booting - something to do with the machine's genlock features. The silverbox contains some extra circuitry to deal with this issue. The straight-through pin adapters do work on later Amigas.

Actually, speaking of genlock issues, have you been running all your tests with the A520 still connected? Just a thought, but try booting up without it and see if it makes a difference. It shouldn't, but if you've tried every other variable...

After that, I think it's time to start playing with the 2320's potentiometer per the manual. While CRTs used to display garbage if something wasn't calibrated correctly, LCDs tend to just give up and not display anything.
Title: Re: How to Use an A2320
Post by: Oldsmobile_Mike on April 13, 2016, 12:01:11 AM
Quote from: raoulduke;807091
I've tired it on like 6/7 monitors one of which was a TV, but I'm in the US.

Thanks Paul; the manual also mentions that mono/Amiga display port connections don't interfere.  But i had missed that at first.  I've gotten a bunch of monitors at this point, the last of which - a Dell E773c has a vertical frequency scanning range that starts at 50hz.  Unless I'm misunderstanding the vertical frequency scanning range thing on the E773c (like unless that doesn't mean it supports 50hz, but I think it means that it does) I think that's a definitive failure with the card.  The E773c senses that its VGA cable is connected but otherwise gets no signal.

Why are you trying to get 50Hz?  You're in the US, get it working at 60Hz (NTSC) before you muck around with PAL settings.

IMHO if you've tried it with seven different monitors and none of them produce a picture (and you've confirmed that the monitors and cables otherwise work), the card is probably toast.
Title: Re: How to Use an A2320
Post by: Matt_H on April 13, 2016, 03:41:57 AM
Quote from: Oldsmobile_Mike;807137
Why are you trying to get 50Hz?  You're in the US, get it working at 60Hz (NTSC) before you muck around with PAL settings.

IMHO if you've tried it with seven different monitors and none of them produce a picture (and you've confirmed that the monitors and cables otherwise work), the card is probably toast.


The 50Hz stuff was just a diagnostic approach on the (since nullified) assumption that this was a PAL machine in Europe - wanted to rule out a 50Hz-incapable monitor as the cause of no display. Now we're onto the hard stuff! :)
Title: Re: How to Use an A2320
Post by: QuikSanz on April 13, 2016, 04:13:14 AM
Amber is from around 1990.Caps?
Title: Re: How to Use an A2320
Post by: raoulduke on April 13, 2016, 08:21:30 AM
I was going to ask about caps.  I think there are really just those two (http://amiga.resource.cx/photos/a2320,1), but I can replace them.  They smell fine but without (your) help I don't really know how to diagnose any of the issues with the card.  I can replace the two caps though.

Matt_H I didn't realize you were working on the assumption that it might be a PAL issue; I could have told you it wasn't.  I got it from its original owner here in New Jersey.  But he hadn't used it in a long time; I'm not sure he realized what condition it was in (regardless of the card), and it also had battery corrosion damage.

Is it possible that traces around the battery affect the display port?  My other thought in addition to the card itself was that the port may not work (properly).

And as for the cable; I just realized I bought a 23-pin to 9-pin VGA... so... but it'll make it slightly easier to graft a homebrew adapter onto the end of it.  Part of the circuit diagram for (essentially) the silverbox is here: http://eab.abime.net/attachment.php?attachmentid=16650&d=1211448710 , and you add a 100uf according to them cap between the VCC and GND.  What does that mean 5v 100uf, then?

And the silverbox looks like it also has extra circuitry on the underside.  What's the deal with that and how limited would that homebrew adapter be?  (http://eab.abime.net/showthread.php?t=36781)  I feel like they were saying it wasn't working properly at 15khz; does that mean it'll only work at 30khz?  Or ... what am I missing here.  Is it just not possible to adapt to VGA...?
Title: Re: How to Use an A2320
Post by: QuikSanz on April 14, 2016, 03:38:29 AM
The 2 you see are of electrolytic type but, every part with a "C" in front of the part # is a cap. All types can go bad after 26 years.

Edit: I count about 32
Title: Re: How to Use an A2320
Post by: Oldsmobile_Mike on April 14, 2016, 04:11:53 AM
Quote from: raoulduke;807154
What does that mean 5v 100uf, then?

It's an electrical measurement.

https://en.wikipedia.org/wiki/Farad
Title: Re: How to Use an A2320
Post by: raoulduke on April 14, 2016, 04:47:53 AM
No, oldsmobile_mike what i meant was that the actual discussion of the schematic mentions adding a 100uf cap but it doesn't list a voltage measurement.  I was curious if someone with more electronics knowledge could infer what the voltage is supposed to be - and I was suggesting that it might be 5v but that is truly a guess.

//

Also the LCD I got the other day can do 30khz and 50hz so I think it'll work.  I didn't realize those other caps were apt to go bad.  On most of my older machines that use those types they've never gone bad.  But I suppose it's possible.  Still for the moment I'd prefer to just be able to ditch the composite output; I've had the amiga sitting on my floor in front of the tv for a week or two.
Title: Re: How to Use an A2320
Post by: QuikSanz on April 14, 2016, 05:00:43 AM
Look again. VCC to ground, Pin 23 is VCC = +5V. They want this in the adapter for a trash filter on the power to the chip.

Edit: A bit large for that. Maybe typo, 10Mf maybe.
Title: Re: How to Use an A2320
Post by: raoulduke on April 14, 2016, 05:08:29 AM
I understand.  I studied electronics a little bit as a young child, but I don't understand the impact of what you're saying.  Are you saying my inference that it needs a 5v 100uf cap was correct, or that it was incorrect?  Better still... could you just please tell me what the answer is?  :)
Title: Re: How to Use an A2320
Post by: QuikSanz on April 14, 2016, 05:14:13 AM
Se edit, yes your assumption is right, 5V, but I question 100Mf. Sounds high to me but the voltage on that bus may have some other heavy current loads causing a fluctuation.
Title: Re: How to Use an A2320
Post by: raoulduke on April 14, 2016, 05:18:33 AM
Thanks; as I said, I really don't know... I'm taking that discussion at face value - as I said because I just don't have the knowledge.  If someone has one of those silverboxes and can check the cap that'd possibly be useful; but I think it's got different circuitry.  [And I couldn't make out a rating in the pics on the site Matt_H posted.]

I mean... I guess putting a cap with too high a rating isn't likely to do damage, right?  (Whereas I think the other way around possibly could?)  I'm happy to experiment a little; wait and what would it possibly damage - the monitor?  I honestly don't care about that.
Title: Re: How to Use an A2320
Post by: QuikSanz on April 14, 2016, 05:22:01 AM
This cap is only designed to keep power clean so 100Mf won't hurt, just have to wedge it into the adapter. Big size diff between 100 and 10.
Title: Re: How to Use an A2320
Post by: raoulduke on April 14, 2016, 05:57:52 AM
I appreciate it.  Thanks.  I have spare PCB; I guess I'll buy a female vga connector - or I may have one, actually.

One last question: The 9-pin vga has a sync ground and separate R, G, and B grounds; the 15-pin vga only has one ground (that hits multiple pins).  So should I just 'tie up' all the separate grounds and just put them all to the single ground of the 15-pin?
Title: Re: How to Use an A2320
Post by: raoulduke on April 14, 2016, 10:47:58 PM
[Well that's my plan for the grounds.]

Yeah so much for last question... Re: the A2320 and recapping, if I'm reading this: (http://www.mouser.com/catalog/supplier/library/pdf/avxmultilayerceramicld.pdf) correctly, it seems to be that the codes are highly dependent on the type of cap.  And I don't know enough to differentiate the caps on the a2320; they should all be visible in the hi-res pics posted earlier [at least to see the types].

The only one that looks substantially different in type from the others is the "101".  And one of mine looks "chipped" or maybe even zapped, subtly though.  So that one would be what I'd replace first and then test before recapping the rest.  Anyway, any help would be much appreciated, but I want to leave the list up in case anyone else wants to recap in the future.

// I don't know if any of the first bit is right...

Code         / #of Caps / Meaning
A5E 104M / 13           / 5V 0.1uf; +/- 20%; tolerance control
476 +16k / 2             / 16V 47 uf
101          / 3             / 0.1nf
019 A5M   / 4             / 5V ?; AVX; +/-20%
334 E5Z    / 3             / 5V 0.33uf; +80%; tol. cntl.
102 C5K    / 1             /
101 A1[4?] / 1
040 ACF    / 1
043 AAM   / 1
045 ACP    / 1
001 AMF    / 1
010 ANP    / 1

And then those two electrolytic caps are 16V 470uf.
Title: Re: How to Use an A2320
Post by: QuikSanz on April 15, 2016, 02:00:58 AM
Quote from: raoulduke;807191
I appreciate it.  Thanks.  I have spare PCB; I guess I'll buy a female vga connector - or I may have one, actually.

One last question: The 9-pin vga has a sync ground and separate R, G, and B grounds; the 15-pin vga only has one ground (that hits multiple pins).  So should I just 'tie up' all the separate grounds and just put them all to the single ground of the 15-pin?


It appears as though the 15 pin has 3 grounds next to RGB pins, so 1 for each color, to keep out crosstalk/color bleed. #5 should be power ground, that's the ground you want.
Title: Re: How to Use an A2320
Post by: raoulduke on April 15, 2016, 03:18:34 AM
"Normally," though, I think they're wired together anyway.  Usually that second row and then a few first and third row pins are wired together.  I can't find my d-sub female connector (to evidence that thought), but: http://www.blogcdn.com/www.engadget.com/media/2006/11/vga_pinout.jpg .  But I can wire them specifically to the pins near the R, G, B; no biggie.  [I am a little curious if that explains a quality issue with my ST adapter, though.]
Title: Re: How to Use an A2320
Post by: QuikSanz on April 15, 2016, 03:35:11 AM
I suppose the layout is for all formats including RCA type cable just put the cap near the chip close to the legs. Maybe underneath.

Edit: Use electrolytic
Title: Re: How to Use an A2320
Post by: raoulduke on April 15, 2016, 07:54:06 AM
Cool.  Thanks.  I couldn't find 5v 100uf caps at mouser or digikey, so I'm going to go with 6.3v.

I think I'll actually make a little PCB connector board and leave the cables detachable on both ends.  I've had not great luck with my 8 or 9-wire Atari ST bus mouse adapter.
Title: Re: How to Use an A2320
Post by: raoulduke on April 24, 2016, 05:33:37 AM
Didn't work [my VGA adapter]... I guess there's a small possibility that I wired it wrong (which I think is unlikely, though) and that starting from scratch would help.

Actually the only thing I couldn't try is the Dell CRT monitor I bought that has (by a wide margin) the widest scanning range - bc it has a male VGA plug and my ... apparatus ... also has a male VGA plug.  So I think I'll start there (with an adapter).

I recapped the two electrolytic 470uf 16V caps on the A2320 but that had no obvious effect.  I bought these 101(-labeled) caps but the ones I got only have two axials/leads and the originals have three.  Is one a ground?  I assume I should just look for another set of caps that have 3?
Title: Re: How to Use an A2320
Post by: raoulduke on April 25, 2016, 05:20:07 AM
Could I be misunderstanding the purpose of all this?  I just wanted a higher resolution display mode.  Currently I'm also locked into max 16 colors.  I just assumed this was a limitation of composite output mode.
Title: Re: How to Use an A2320
Post by: guest11527 on April 25, 2016, 06:44:52 AM
Quote from: raoulduke;807511
Could I be misunderstanding the purpose of all this?
Probably.

Quote from: raoulduke;807511
I just wanted a higher resolution display mode.
You don't get one. You get a higher frequency output to be able to connect a standard VGA monitor to the system. You get the interlaced modes without flicker.

Quote from: raoulduke;807511
Currently I'm also locked into max 16 colors.  I just assumed this was a limitation of composite output mode.

No, that's a limitation of the chip ram DMA bandwidth. The flicker fixer cannot change that in any way.
Title: Re: How to Use an A2320
Post by: raoulduke on April 25, 2016, 06:51:55 PM
Can you explain the chip ram DMA bandwidth issue?  Or is there an easy link that would explain it?
Title: Re: How to Use an A2320
Post by: kolla on April 25, 2016, 07:06:45 PM
Quote from: raoulduke;807541
Can you explain the chip ram DMA bandwidth issue?  Or is there an easy link that would explain it?


You are essentially asking why buying a new fancy TV does't make the picture quality from your ancient VCR any better. The "chip ram DMA bandwidth issue" is simply that it is too low for higher resolutions, and those who designed it knew that much.
Title: Re: How to Use an A2320
Post by: Oldsmobile_Mike on April 25, 2016, 07:14:16 PM
Quote from: raoulduke;807511
Could I be misunderstanding the purpose of all this?  I just wanted a higher resolution display mode.

Get a real graphics card.  Or even an Indivision ECS offers several additional higher resolution modes (HighGFX, SuperPlus, HD720).
Title: Re: How to Use an A2320
Post by: paul1981 on April 25, 2016, 07:14:49 PM
Quote from: raoulduke;807511
Could I be misunderstanding the purpose of all this?  I just wanted a higher resolution display mode.  Currently I'm also locked into max 16 colors.  I just assumed this was a limitation of composite output mode.


It sounds as though what you're looking for is a Zorro graphics card. These will give you higher resolution screen modes in Workbench with more colours. You'll be also wanting a CPU expansion to drive it though, so there's more expense...
Title: Re: How to Use an A2320
Post by: guest11527 on April 25, 2016, 07:24:47 PM
Quote from: raoulduke;807541
Can you explain the chip ram DMA bandwidth issue?  Or is there an easy link that would explain it?

Well, with the clock rate of the custom chips as low as it is, and the amount of data lines between the ram and the custom chips, there is a certain upper limit of how many bytes can be pushed out of the display at a time, and that limits the available resolution and the available number of bitplanes.  

The OCS/ECS chip ram bandwidth saturates at 4 hires bitplanes, or (theoretically) at 8 lowres bitplanes. At that rate, the maximum amount of data theoretically possible goes from the RAM to the custom chips.

At that time, this was the highest achievable rate possible with state of the art technology.

Nothing can really fix that, within the limits of the ECS machine, this is as far as it gets.  

If you want more colors, or higher resolution, get a graphics card.

CBM had a special monitor, the A2024, that also accepted refresh frequencies as low as 15Hz to enable higher resolutions. This monitor had an internal framebuffer to quadrupel the frequency from the system to the actual tube. There is some custom support in the Os to enable it - it requires a very specific chip setup to send an entire video frame in four iterations (four tiles) to the monitor.

The standard flicker fixer cannot do that. It can buffer a field (half a frame) to double the vertical frequency of interlace screens, but that's as far as its operation goes. It cannot interpret the special A2024 modes. (Which are really just a hack in the system).
Title: Re: How to Use an A2320
Post by: guest11527 on April 25, 2016, 07:40:51 PM
Quote from: Thomas Richter;807548
CBM had a special monitor, the A2024, that also accepted refresh frequencies as low as 15Hz to enable higher resolutions.

Now that I look it up, it is even as low as 10Hz. Surprisingly - I didn't know this before - there was *also* a custom flicker fixer that essentially used the same logic the A2024 had, but fitted it into the video slot and gave you the same resolutions the A2024 had - based on the same exotic technology, with the same drawbacks (slow refresh, of course!).

Here's more information: http://amiga.resource.cx/exp/moniterm

No, it's not useful technology I would recommend buying. A graphics card is the better investment.