2MB Chip RAM directly on A500 rev. 6 motherboard?

[alexh]

You'd never sell any at $150-200!

This vendor has access to the back stock and has sold several of these for $90 in the last year or two.

Plus who in their right mind would pay $200 for a MegaChip when you can get an A500+ for $3-10

[alexh]

Same guy sold one recently for $99

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320282336765

I think I bought mine from this same guy 3-4 years ago for $59 which goes to show how many he's got / had.

redrumloa wrote:

alexh wrote:who in their right mind would pay $200 for a MegaChip when you can get an A500+ for $3

Err, right :lol:

Right.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=300266237314

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=300265527532

Wedge shaped Amiga's are practically worthless.

redrumloa wrote:
I just sold a reglular A500 with imperfect case for 10x more than $3 and it sold like lighting at that price.

Maybe the redrumloa in the auction makes it worth more. A sort of provenance?

[alexh]

I am just trying to urge people who might be reading this and considering paying those prices to stop and think again.

A500, especially in UK, is worthless. Millions were made and there is a large supply of them even the 2Mbyte capable A500+

Hold out for a bargain. I guarantee you wont have to wait long.

P.S. I would never recommend an A2000. They are the worst Amiga. They have no redeeming features.

[alexh]

Oh come on! They dont :-)

No AGA, no scandoubler, no Zorro III, no IDE. Unless you already have one, or can get one for free, you steer clear.

I imagine that MegAchips mainly end up in CDTVs? It's what I bought mine for.

They are the only Amiga where there is no real upgrade alternative. (CD32 just isn't the same)

[alexh]

redrumloa wrote:
Why don't you open am eBay store and sell this hardware for what you think is fair?

Totaly off on a tangent, I dont understand the economics of eBay for most second hand vendors. I cant be arsed to sell any of my old stuff via ebay. I can make more money doing something else in the time it takes to compose the advert and go to the PO.

[alexh]

tabuhuso wrote:
2mb DKB megachip no working on ecs PAL amigas...

Yes they do!! But you need a PAL version. (The ones being sold on eBay are mainly NTSC ones)

If you have an NTSC version you need to make a note of the EXACT model of 8375 Agnus in them and replace it with it's corresponding PAL version. They must be the same because the pinout changes between variants.

i.e. If your NTSC DKB MegAChip has a

8375 318069-11 replace it with 8375 318069-10
8375 390544-02 replace it with 8375 390544-01
8375 318069-19 replace it with 8375 318069-18

You can buy PAL 8375 Agnus chips from Amiga Center France for about €45 each (which is not cheap after you've already paid $89 for the MegAChip!) or you can scavenge them from broken A600's (if you have a hot-air gun) & A500+'s (which tend to break due to their battery leaking)

amigaksi wrote:
I have an Amiga 500 with 2MB chip ram; don't recall which revision of motherboard it is but there's no DKB or any other expansion installed.  

It's an A500+ (rev 8a)

[alexh]

Yes, NTSC on the left PAL on the right.

I have *some* documentation on the pin changes between the different Agnus main variants (8370, 8372, 8372AB, 8375) but very little on the differences between the minor variants.

Not for trying, I've run several threads to try and nail down Agnus details. Of all the Amiga chips it is the one that changed the most and known the least.

Amiga.org thread

EAB Thread

EAB thread about pinouts

Newsgroup thread

[alexh]

8372B 318069-03 is on record as having been seen in an NTSC A3000D. But I do not think it is accurate to call it NTSC. I *think* all 8372 Agnii are dual standard supporting both PAL & NTSC (at least some are). So this board probably works with both although you might need to mod your Amiga motherboard depending on its PCB version to make it drive the NTSC/PAL select pin correctly.

There is no direct mapping between model numbers and machines.

Rule of thumb:

A500+ = 8375 390544-01/2
A600  = 8375 318069-10/11
A3000 = 8372AB / 8372B 318069-03

But it is just a rule of thumb and it doesn't always hold true. Later revisions of A500+ motherboards sometimes have 318069-10/11, early A600 motherboards have 390544-01/2 and later revisions of A3000 have 8375 318069-18/19

[alexh]

A600 use AGNUS part numbers 390544 only on v1.0 motherboard. They use 318069-10(pal) and 318069-11(ntsc) on motherboards v1.3, 1.5 and 2D. No idea what the pinout differences are (if any).

I found it difficult to read the pin numbers on the A600 schematics I could find online they are too blurry. The ones I found had no validation data either (i.e. you've no idea where they came from, which motherboard version they correspond to or which agnus chip is described on them)

[alexh]

http://aminet.net/docs/hard/2MegAgnus50d5.lha
http://aminet.net/docs/rview/TwoMegAgnus.txt

Heh I guess you couldn't read the A600 one either.

[alexh]

The schematics look similar but the pin numbering is subtly different. Enough to make re-wiring a no go.