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britlord
9th February 2015, 23:25
Guys. I bought a 500 v6 Motherboard, that had no video. You see. I pressed the Denise chip in and Yeee Haa. The kickstart screen came on, so I bought a bargain here..:D I've now done the 1MB chip ram mod and did the 2 jumper cuts. But I notice that a track going to one of the JP4 pads is cut (It's next the the Angus). Anyone know if commodore did it or is there a reason why that was done.. Also, I can't get it to boot-up with a 3.0 kickstart rom (before the chip ram mod was done). Bad rom???? or was it because only 512k of ram...

voyager_1701e
9th February 2015, 23:33
Assuming you mean 3.1 ROM...as the A500 didn't have a 3.0 ROM upgrade available?

Sorry cant help with your question though :(

britlord
9th February 2015, 23:40
so that's why the rom didn't work. what Amiga has a 3.0 rom then...

Thanks..

BLTCON0
10th February 2015, 00:47
But I notice that a track going to one of the JP4 pads is cut (It's next the the Angus). Anyone know if commodore did it or is there a reason why that was done..

JP4 controls pin41 (PAL/NTSC) behaviour.
PIn41 grounded (JP4 shorted) the 8372A/B Agnus will assume an NTSC oscillator is present and behave accordingly.
Pin41 floating (JP4 open) the 8372A/B Agnus will assume a PAL oscillator is present and behave accordingly
Seems the cut track was meant to configure the Agnus as "PAL". The proper way would be to cut the bridge between the JP4 pads - that way it's easily undone with a solder blob. Post a photo if you can to assess damage.



Also, I can't get it to boot-up with a 3.0 kickstart rom (before the chip ram mod was done). Bad rom???? or was it because only 512k of ram...
As the 3.0 ROM was launched for 32-bit Amigas (A1200 and A4000), it is a two-chip part (32-bit = 2 x 16 bit) , chip1 contains words 0, 2, 4 etc and chip2 contains words 1,3,5 etc, so unless you have a custom-burned single-chip 3.0 ROM (16-bit), you're trying to boot the Amiga with half the ROM data :) (and not even a contiguous half of it, too).
Software-wise, the 3.0 ROM can boot the A500 fine, it was used in some Viper/E-Matrix accelerator or something like that.

britlord
10th February 2015, 01:18
This is what I can see. The JP4 pads are not joined together. Just the track going to left pad was cut, so I soldered a wire from the track hole to the pad (Under the board the track goes to the Angus chip), as for the oscillator. Its 28.37516 MHz, and the 3.0 rom. It is a original Amiga one (391523-01). I just don't know where I got it from LOL..

BLTCON0
10th February 2015, 01:53
This is what I can see. The JP4 pads are not joined together.

Which would be normal for a PAL configuration.


Just the track going to left pad was cut, so I soldered a wire from the track hole to the pad (Under the board the track goes to the Angus chip),


Not sure which view of the board you have in mind when saying "left", but the JP4 pad which is closer to the Agnus socket is meant to be connected to pin #41 of the socket. And the JP4 pad which is farther from the Agnus socket is meant to be connected to Ground.



as for the oscillator. Its 28.37516 MHz,

This is the frequency for PAL, so either it's a PAL build or a fully converted NTSC one.



and the 3.0 rom. It is a original Amiga one (391523-01). I just don't know where I got it from LOL..
That's indeed half of the A1200 ROM :)

britlord
10th February 2015, 02:24
I mean the pad further away from the Angus chip... If you follow the trace. From the pad, down the hole, other side of the board, and straight to the one of the Angus pins.. You see I bought the board from the UK, so it's PAL build.. If you bridge the pads, then the bottom track joins the other pad track (That goes to the Angus too)

Oh the rom. I'll throw it in the trash LOL...

BLTCON0
10th February 2015, 04:00
I mean the pad further away from the Angus chip...

This pad is grounded... it doesn't lead to any hole.


If you follow the trace. From the pad, down the hole, other side of the board, and straight to the one of the Angus pins..

This is wrong. It's the pad that's closest to the Agnus socket that should be connected to pin #41 and only that. The other, away from the socket, pad should not be connected to any Agnus pin, it should be connected to ground (it already is). Undo the connection to that other Agnus pin because now you're incorrectly grounding an Agnus pin!



You see I bought the board from the UK, so it's PAL build.. If you bridge the pads, then the bottom track joins the other pad track (That goes to the Angus too)


Here's a photo with the whereabouts of JP4.83008

britlord
10th February 2015, 04:28
Ok, so what you mean is that the one pad is ground and the other one goes to pin 41 on the Angus chip. But where goes the top track go from the hole. It look liked that it went to the ground Pad, as the cut was there. Not between the pads, so that's why I was confused (hard to see with the silkscreen right over the track)

Thanks for letting me know...

BLTCON0
10th February 2015, 10:57
No prob :thumbsup:
Here's another closeup - from your description it seems the cut is on the red track.

britlord
10th February 2015, 15:02
Yeah that's it. Though why would the red track be cut...