How to Use an A2320

[raoulduke]

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).]

[raoulduke]

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?

[raoulduke]

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.

[raoulduke]

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.

[raoulduke]

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?

[raoulduke]

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.

[raoulduke]

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.

[raoulduke]

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.

[raoulduke]

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.

[raoulduke]

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.

[raoulduke]

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...?

[raoulduke]

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.

[raoulduke]

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?  

[raoulduke]

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.

[raoulduke]

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?