Different versions and revisions of Amiga 1200?

iddqd

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What are the differences of the various revisions of the motherboards of Amiga 1200?

Also, are there any differences between a "Made in UK" and "Made in Philippines" Amiga 1200?
 
What are the differences of the various revisions of the motherboards of Amiga 1200?
That's a weird story, better ask something more specific. If you're looking for the most easily obtainable, generally "foolproof" board, that's probably the 1D.1 with an 1D.4 sticker (i.e. 1D.1 PCB factory-upped to 1D.4 specs) but everyone has their own experiences.

Also, are there any differences between a "Made in UK" and "Made in Philippines" Amiga 1200?
No. Maybe they have different shades of green on the PCB. If you're asking if one is "better built" than the other, I have no idea, but I wouldn't think they're any different that way, either.
 
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That's a weird story, better ask something more specific.
Well, I'm just looking to be educated, and was hoping there would be a write up or wiki somewhere going through this, as I'm (almost) new in the Amiga scene. (For some reason I only used my Amiga 500 to play games, and wasn't interested back then in the "nerdy" tech details that I am now)

Anyway, thanks for the info.
 
The thing is even a given revision can be different in various production runs. In a nutshell:
Named revisions are:
1A, 1B, 1C, 1D, 1E and 2B. 1C is likely the 1D precursor and 1E a precursor to 2B, so you won't come across them.
1D has subrevisions: 1D.1, 1D.2 (very uncommon), 1D.3 (uncommon), 1D.1 -> 1D.4, 1D.4 (Commodore version), 1D.4 (Escom version)
2B also exists as a Commodore version and an Escom version.
Due to the series of 1D subrevisions, the timeline is most likely 1D.1 < 2B < 1D.4, so 2B is not necessarily more recent than 1D.4, there's some overlapping.

1A has full clockport headers (may interfere with some expansions) and "incorrect" resistor values for the audio circuit (1.5 kOhm instead of 680 Ohms)
1B is rather solid, one full clockport row instead of two (may still interfere), audio resistors corrected
1D.1 / 1D.4 are the most common, 1D.1 also exists factory upped to 1D.4 as already stated. A visible difference is "pure" 1D.4's don't have a link wire which is visible on 1A through 1D.1 boards. Upped 1D.4s do have it.
1D.4 Escom version usually lacks the RDY signal for the floppy drive, having replaced it with the CHNG signal. There's a link wire underneath between pins #2 and #34 of the floppy connector. Disconnecting it from pin #2 and resoldering it to pin #1 of the external floppy connector brings the board back to Commodore specs and allows genuine Amiga drives to be used correctly. The same applies to 2B Escom version, although strangely some are identical to the Commodore ones (no wire) and don't need any modification.
1D.4 has a detachable mouse port, so does 2B but in the form of a plug-in board.

Some 1D.4 boards have the partial clockport header on the left side of the row instead of the (correct) right side. Factory blunder, but can be corrected with some desoldering/soldering.
2B boards have solder spots for a header to easily connect an Amiga 500 keyboard, bypassing the handicapped A1200 keyboard controller that way.

Lisa chips have been produced by Commodore, HP and NCR. They're functionally identical but plugging an Indivision 1200 scandoubler/flickerfixer can be a hit and miss deal with respect to proper contact. Everyone has their own story with this, but generally the Commodore version is more likely to work "out of the box" without sanding the Indivision socket. The MK2 version is supposedly more tolerant.

Budgie has been produced in two versions, earlier boards may consistently have the -01 version, with later boards it's more or less random.
(If you want to get very geeky, even the plastic casing and the LEDs have undergone two revisions :p )

Complete Escom systems (with the floppy-handicapped 1D.4 or 2B boards) also don't have a genuine Amiga floppy. After fixing the board, it must be replaced or converted for Amiga use.
Genuine Amiga floppies for the A1200 usually come from Chinon, Teac, Panasonic and maybe Epson. The keyboard comes exclusively from Mitsumi and the keys are identical to the A500 Mitsumi ones, so if perfect colour matching isn't an issue replacements may be obtained from A500 ones. In fact, the A1200 keyboard plastic base has a crossed-out "A500" engraving.

All revisions have a PCMCIA reset problem, there exist both hardware and software fixes.
All systems more or less function well on a basic level. When pushed by expansions etc problems may occur, this has gained the collective name "timing bugs". For a rather thorough treatment of the subject, consult this page. Some history on the subject also here.

Some other info and photos here.
And some more info and photos here.
You'll see more subtle differences on the photos: Modulator size, power filter shape, RAM chip size. Just look around.

Some ideas on floppy modifications (convert PC floppies for Amiga use) here.
The AmiOracle section here is also a good source of general info.

This will keep you busy for a while :) Just keep reading and you'll soon get past the "overwhelmed" stage. Any other question, ask away and someone will likely jump in.
 
Wow, big thanks! A lot of info there. This will keep me a long while.
 
Sorry to dig up an old thread, but I did quite a bit of searching trying to identify my new replacement board. It is a 1D (period, without no subrevision). Is this correct, or is it actually a 1d1 board? See the attached picture. I have little or no info regarding this when it comes to compatibility, stability issues and the like. So if it is an 'ugly duckling' revision I would like to know...

a1200_1d.jpg
 
It's obviously correct, the pics in BBOAH have also been recently amended with a "pure" 1D board courtesy of Dave Haynie.
They both have late 1992 datestamps, so it may be that a small initial 1D batch was made.
Perhaps you could post a full photo of the board?
Stability/fixes-wise I wouldn't expect it to be much different from 1D.1, that is mostly trouble-free. Only look into fixes if you encounter specific problems.
 
Thanks for the input, @BLTCON0. I have done some tests with the board, and I notice that E123C & E125C have also been removed. Did not check the Budgie rev. yet, but I assume it is probably Rev0.
It seems to not be as picky with accelerator cards as the 1d4.

I can post a full photo if it is of interest! :)
 
A photo is always of interest!
Especially to see if any particular factory rework has been done. At times it feels as though every A1200 that came out of the production line had its own personalised reworks done (ok slight exaggeration here :) ).

As for revision pickiness, I think so too, although it's barely possible to make any sound predictions when it comes to the A1200 :)
 
I've added some pictures of this rev. 1d (period) board now - sorry for the delay. :cool:

btw. I'm experiencing a very curious issue with it when compared to my other rev. 1d4 board: the middle mouse button does not work with this board(!). (LMB/RMB both work, in both CN1+CN2 ports, no other issues with mice or joysticks were detected). Could it be bad CIAs, or a different issue? The board was supposed to be 100% working (refurbished)

Anyway; I hope the pics are of some use!
 

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[btw – I realize the previous comment relating to the middle mouse button might sound a bit weird as no Ami-mice that I know of had this. The issue was with a DB9-to-USB adapter (TOM+) where the middle mouse button worked with my existing 1d4 board.]

Is this some kind of defect with the board/chips (CIAs?) Or are the 1d & 1d4 boards really that different? The board was supposed to be fully recapped and tested... (not something I am able to verify)
 
[btw – I realize the previous comment relating to the middle mouse button might sound a bit weird as no Ami-mice that I know of had this. The issue was with a DB9-to-USB adapter (TOM+) where the middle mouse button worked with my existing 1d4 board.]

Is this some kind of defect with the board/chips (CIAs?) Or are the 1d & 1d4 boards really that different? The board was supposed to be fully recapped and tested... (not something I am able to verify)

The CIAs (actually one of the CIAs) only take input for the left mouse button on each mouse port, middle/right mouse button detection is a different story and not CIA related, the pins connect to Paula.
 
[btw – I realize the previous comment relating to the middle mouse button might sound a bit weird as no Ami-mice that I know of had this. The issue was with a DB9-to-USB adapter (TOM+) where the middle mouse button worked with my existing 1d4 board.]

Is this some kind of defect with the board/chips (CIAs?) Or are the 1d & 1d4 boards really that different? The board was supposed to be fully recapped and tested... (not something I am able to verify)

The CIAs (actually one of the CIAs) only take input for the left mouse button on each mouse port, middle/right mouse button detection is a different story and not CIA related, the pins connect to Paula.
That's useful to know, thanks. So the issue is potentially with Paula. The RMB does work properly, though, in both ports. No sure what other diagnostics I could run to verify if there is a defect as Paula at least appears ok wrt. sound and floppy operations.
 
@BLTCON0: do you know which pins on Paula control the RMB+MMB mouse detection? If there is a schematic for this somewhere it could also prove useful. (Again, it is quite weird that it works properly on rev 1d4 but not 1d.) :)
 
its on pins 35 and 36 i think,reading the schematics would of got you that answer

it should work properly on both,they are essentially the same

there is a program on aminet for testing the ports,i think its called joytest
 
Thanks @roy. Yes, I could have checked the schematics but I do not have those. ;) I use Keir Fraser's SysTest program to test the buttons, btw. It is also very useful for other diagnostics.
 
Does anyone have access to the schematics, btw.? I can't seem to find them, and it would be interesting to determine whether there is a difference in the MMB detection for the older 1d board as opposed to the 1d4 rev. where this works – or whether there is some strange defect within this particular 1d board itself.
 
@Drag0nFly
The schematics can be found scanned around the web, google is your friend, they have also been reworked and available as hi-res PDF at amiga wiki.

But IIRC right/middle button reading is not direct 0-1 logic level as with the left one, the circuitry is a bit more involved (which is why you won't see any boot-time switchers/selectors using the right mouse button, it takes some 68k code to decide its state. On the other hand the state of the left mouse button is directly available on the relevant CIA pin).
 
Thanks once again @BLTCON0, and for the AmigaWiki link. I'm a little more enlightened looking at the schematics. I see the first PDF covers rev 1 -> 1d (and if that implies that it covers both 1d & 1d4 boards there, presumably, isn't any difference between the two?) The only other PDF is for rev 2, which has a slight difference in the CK_I signal on U34, from what I can see.

So basically it is pins 35+36 and 38+39 which hook up to the left/CN1 & right/CN2 ports respectively (which in turn has four of the pins hooked up to U34 as well). Interestingly neither U7 or U8 is involved in any of this.

But as you say, the circuitry is probably more involved for the rmb/mmb. Although I certainly did not get any smarter as to what exactly from looking at those schematics. (But perhaps the person designing the DB9 mouse adapters will!)
 
Yes the schematics are good for all (up to) 1D revisions, the differences are minor and mostly down to some form factor details, the PCB is largely the same.
Some discrepancies that exist are immaterial.
For proper right/middle button detection see the hardware manual, chapter 8, pages 234/235. The button state reading procedure is outlined there.

For more conclusive testing, isolate the middle button pin and wire a separate switch to it. That'll leave the USB-DB9 adapter out of the equation.
 
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