Wanted to Buy: Agnus Chip for A2000

[Argus]

@magnetic

send me your snail mail address and I'll post a NTSC 8370 512K  Agnus on Monday, gratis....

[alexh]

Before you send it him, any chance of a quick photo of it? I am collecting a database of AGNUS types and manufacture dates.

If not a photo, then post the numbers on the top of the chip.

[Argus]

Sure, it's a MOS chip 8370 with the numbers 4187 23 below.

[alexh]

Thanks (a picture would still be cool hint hint :-))

[Merc]

magnetic wrote:
Merc

Great. Thank you! I'm also looking for a 1.3 Rom for an a500/a2000...

Well you might be in luck!  I'm sure there's one  of those kicking around too...  I'm going to take a look this afternoon  and see if I can track down the Agnus if you still want it, maybe a 1.3 chip will turn up as well.

[Zac67]

The pinout differences of PLCC Agnuses are extremely small - not 100% sure if they are completely interchangable though.

However, any 512K/1M Agnus will run in any A500, A2000(B) or CDTV (with proper A19 line jumper setting) - I'm only unsure about the 2M types (A500+, A600, A3000).

[Generale]

Zac67 wrote:
The pinout differences of PLCC Agnuses are extremely small - not 100% sure if they are completely interchangable though.

However, any 512K/1M Agnus will run in any A500, A2000(B) or CDTV (with proper A19 line jumper setting) - I'm only unsure about the 2M types (A500+, A600, A3000).

I think the 2mb ones are a fairly major undertaking to retrofit. Doesn't mean I wouldn't try if given the chance  :-)

[Speelgoedmannetje]

Here is an interesting link :-)

[alexh]

I dont believe the information here is accurate.

[Zac67]

I definitely don't recommend using a screwdriver, those old sockets break VERY easily. If you remove the board, you can push through the holes from below - but CAREFUL!!

[Speelgoedmannetje]

alexh wrote:
I dont believe the information here is accurate.

Could you be more specific?

[alexh]

It says

you need an 8372A or an 8375 Agnus

That isnt true, you cannot use just any 8375 Agnus. For a start 8372A Agnuses are both PAL and NTSC while 8375 ones are two different chips. Get the wrong one for your motherboard and things wont work.

8375 Agnuses have at least 2 different pinouts. Wrong one and it is BANG you've fried your motherboard.

There is also the 8375B variant which may (but it is not confirmed) be designed for direct replacement on A2000 boards

http://www.aminet.net/package.php?package=hard/hack/A2K_agnus_hack.lha

But I would not try and fit one without much more research.

[Speelgoedmannetje]

Phew, this is not something I will do again.
I'll rather get myself an a600hd or something like that.
I installed the chip, wich ran, though the screen was aligned wrong and some games didn't run or were running with glitches, or were running too fast (I didn't do the modification mentioned on that site yet).
And I just did the modification, but then the Amiga (Amiga 500) crashed from the beginning; no video output at all. Then I soldered everything back as it was and put the old agnus (8371) back in. Everything's working fine again.
Scratching solder points away from the motherboard, 'tis not something I do regularly, or well, never, I don't know how many etched layers there are on such a board. :nervous:

[alexh]

You need to research Amiga hard hacks, especially Agnus ones thoroughly before attempting them.

You have to know all the niggles about the version of motherboard you have (relevant to the hard hack).

You have to know the hard hack inside out.

If it involves replacing chips (like an Agnus hack) you need to know all the different variants and numbers etc. and be absolutely sure that this is the right one for you.

If you tell us which A500 motherboard you have, which region (PAL/NTSC) which agnus it was fitted with and which agnus you tried to replace it with and maybe we can help?