A500 and jumpers situation - how to get the rest of mem

[JackTheKnife]

Suspects:
- A500 Rev. 5 + Super Agnus
- ICD AdRAM 540 (all full banks of mem)

Acording to the manual (
http://.com/files/17443567..._560D.pdf.html) I should to have additional 4MB of mem but I have only 512kB more and all is 1MB Chip, even I will put all or only 512kB anywhere on AdRAM 540



I did mobo inspection and found those situations:

JP2:



cut the line aka JP7:



JP3:



Why all of them was cut for? And each jumper is for?

According to the AdRAM 540 manual to get 1MB of Chip (marked red on the picture above) user needs to solder wire between JP2 and JP2-2 from AdRAM 540 (photo below).



A person from I bought that A500 doesn't know nothing about those changes because he is only "eBay basement store" (somebody left A500 for sale).

The final question is what was the purpose to do those modifications on mobo and what I need to do to get 1MB of Chip and the rest of mem to work (as manual said).

[Zetr0]

hmm

looking at the pictures that motherboard has had the 1mb chip hack done to it. If so you will have to (undo) it for the card in the trapdoor to work properly.

what revision is the motherboard btw?

[JackTheKnife]

Originally Posted by Zetr0

hmm

looking at the pictures that motherboard has had the 1mb chip hack done to it. If so you will have to (undo) it for the card in the trapdoor to work properly.

what revision is the motherboard btw?

As I mention above - Rev.5

But why he used to do that and lost 3MB from the expansion card? He can do this according to the AdRAM 540 manual without hacking mobo. Also why he hack JP3 when only needs to do JP2 and JP7? How to undo this (which connections are correct). I know only JP7 how to fix. Also what will happen when I will connect JP7 to JP2-2 from AdRAM board?

[JackTheKnife]

Help me, Zetr0-Wan Kenobi; you're my only hope

[JackTheKnife]

Can anybody tell me what is JP3 for and which one position is default? I want to redo everything to get regular A500 then go over AdRAM 540 manual.

[prowler]

Hi Jack,

Have a look on this page:
http://www.amiga-hardware.com/showhardware.cgi?HARDID=8
They have some hi-res pictures of A500 motherboards. See if they can give you a clue regarding the JP3 default setting.

[Edit] I have an A500 English User's Manual, but it only makes one reference to motherboard jumper settings: "U32 and JP2 are mutually exclusive" in one of the schematics

[OddbOd]

Good god, that motherboard has certainly been butchered.

To repair it all you should have to do is clean the excess solder off JP2 ensuring there are no connections between any of the 3 pads then solder the jumper wire between the middle pad and the Gary adapter. Now bridge the lower two pads of JP3 and reconnect JP7 (this should not be strictly necessary but do it anyway).

I believe JP3 sets how the Column Address Strobe lines are connected on a Revision 5 motherboard but you would be better off asking Chain/Toni/Jope/<insert name of hardware geek here> as I don't understand the implications of the modification made to your board.

[JackTheKnife]

True, mobo has been butchered IDK who had that A500 before but he was not good geek

[Chain]

JP2 is A19 adress line, on this mobo is switched to expansion port, which causes you are usin whole adram as chipram. desolder upper blob and solder wire from middle pin to adram jp2-2 asi oddbod says.

now other jumpers..

[JackTheKnife]

What about JP3 and JP7? Why JP3 was modded?

[Chain]

JP3 is a RAS0/1 espansion switch, in original state are pins 2-3 connected (middle with lower).
If manual doesnot mention it, just reverse it to this state.

and gimme a sec there is a ful room of schematics now and i barely can see a table .)

[JackTheKnife]

It looks like somebody cut JP3 (middle off the bottom) and try connect top/middle to somewhere else. Also I can see some soldering near "JP7" (try to connect to somewhere else).

Big thanks anyway!

[Chain]

jp7(A) is a EXTICK signal, if its unrepairable on that small space just connect wire from expansion connector to nearest solderable place (and meanwhile excuse my english )

[JackTheKnife]

My English is not perfect too. Just came to US from Poland

[papa_november]

Any chance someone could re-post that manual? The link has expired.

[prowler]

Originally Posted by papa_november

Any chance someone could re-post that manual? The link has expired.

It's in the Zone for you.

[papa_november]

Thanks!

Has this been submitted to the appropriate places yet?

[prowler]

Yes, it's also on the EAB File Server.

And now that it's in the Zone, thals will make sure it's added to the Amiga Hardware Database.