A500 (r6a) 1MB CHIP RAM Modification: Caution dialup users: excessive H/W pr0n!

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16th February 2010, 23:08
Zetr0

A500 (r6a) 1MB CHIP RAM Modification: Caution dialup users: excessive H/W pr0n!

Hello there my fellow AmiBayers

Recently I put up for sale a 512KB A500 Upgrade -

If plugged into a Basic A500+ it adds it to the CHIP ram (giving 1.5MB CHIP), however if plugged into a basic A500 it would add the 512KB as OTHER ram, thus leaving the precious CHIP ram at 512KB =(

Well we cannot have this so here is a modification that you can do at home with just a craft knife, two track cuts and a soldering iron.

Skills Required

1. Ability to handle a *sharp* craft knife
2. Basic multi-meter use *continuity mode*
3. Ability to solder one point

First Notice

This (HOW TO) is based on a Rev6a A500 motherboard, with an 8372a Agnus, If I find an older board I will do a how-to as well.

Second Notice

If you perform these alterations it is on your OWN ONUS; that means if kill the A500, you hurt yourself or others,or blow-up the street its YOUR FAULT, you do this on your OWN responsiblity

This disclaimer includes but is not limmited by you wanting or having the urge to sing anything by "Barbra Streisand", "Wham" or "Miami Sound Machine" has NOTHING to do with me.

Now, with that in mind we can begin =)
16th February 2010, 23:11
Zetr0

[update]

Sadly the sever housing these images no longer exists, as such some images have been lost.

Overview of the Mod
http://s6.postimage.org/53hat1xkh/A500_6a_1_MBCHIP.png

With Jumper location JP2 (cut and soldered)
http://s6.postimage.org/nllndafch/jp2_zoom.jpg

with Jumper location JP7A (trace cut)
http://s6.postimage.org/uas6tb0oh/jp7a_zoom.jpg
16th February 2010, 23:18
Zetr0

Before the Modifcation

heres JP7A (click to enlarge)
http://www.guildserver.co.uk/data_im...efore/jp7a.jpg

Heres what Workbench says (click to enlarge)
http://www.guildserver.co.uk/data_im.../workbench.jpg

Need to get a *before* shot of JP2.... I forgot.... wheres that time machine got to?... i know its around here somewhere...
16th February 2010, 23:23
Zetr0

Modding Time

JP2 CUT
http://www.guildserver.co.uk/data_im...ing/JP2-00.jpg

JP7A CUT
http://www.guildserver.co.uk/data_im...dding/JP7A.jpg

JP2 SOLDER
http://www.guildserver.co.uk/data_im...ing/JP2-01.jpg
16th February 2010, 23:27
Zetr0

After Modification

As they say on most cooking programs - is should look like this =D

JP2 (click for larger images)
http://www.guildserver.co.uk/data_im.../after/jp2.jpg

JP7A (click for larger images)
http://www.guildserver.co.uk/data_im...after/jp7a.jpg
16th February 2010, 23:35
Zetr0

Testing the Modification

JP2 - Cut (testing disconnection of pad 2 and 3)
http://www.guildserver.co.uk/data_im...P/test/JP2.jpg

JP2 - Solder (testing connection of pad 1 and 2) *click to enlarge*
http://www.guildserver.co.uk/data_im...st/JP2-out.jpg

JP7A - Cut (Testing disconnection of pad 2 and 3
http://www.guildserver.co.uk/data_im.../test/JP7A.jpg
16th February 2010, 23:47
Zetr0

Making it Happen

So finally -

we have cut two traces and soldered two pads together -
we have also tested (continuity) to make sure our work is sound -

Whats next?

Turning it ON!!!!

Heres the Lashup - A500 with A501 and A500HC+ (8MB RAM)
http://www.guildserver.co.uk/data_im...after/jig2.jpg
(going to point out that the SCSI controller is connected to a SCSI->IDE adapter with a WinUAE formatted and prepped (OS3.1) on a 4.1GB HDD)

And there is LIFE!
http://www.guildserver.co.uk/data_im.../after/jig.jpg

Whats Workbench Say? (tell me tell me TELL ME!!!!) *click to enlarge*
http://www.guildserver.co.uk/data_im...workbench2.jpg

And there you have it, this took no more than 25 minutes to do AND I was taking pictures... this shouldn't take anyore more than 15 minutes in thier own home... just remember if in doubt ask before blowing somthing up.
17th February 2010, 00:00
inoel

dont have the ram cards yet can i pay any of you to do this for me ?
I will be geting two a500 in march also need 3.1 roms in them
17th February 2010, 00:00
Zetr0

Quote:

Originally Posted by keropi

this thread will be awesome to the max :bowdown:

Thanks my friend, this was a quick one -

Its important to note that IF one wanted to, you could populate the empty memory spaces at the bottom of the motherboard

http://www.guildserver.co.uk/data_im...efore/jp7a.jpg[I]

if you notice in the above picture, at the bottom of the board is the chip-memory - you will also notice that there are 4 unpopulated spaces -

With this mod - you can poluate those spaces with 4 20 pin 256x4 DIP memory modules - Thus rendering the trapdoor interface - for the most part - redundant.
17th February 2010, 00:01
r0jaws

Nice Tute chap,
I think anyone should be able to give that a go. :D
17th February 2010, 01:49
rkauer

Excellent tutorial, my friend!

I'm still looking for some spare time to dig a go on turning the trapdoor expansion into FAST RAM and using the spare spaces on the mobo to expand the chip RAM.

An humble A500 with 1Mb Chip & 0.5Mb (not so) FAST is a lovely machine on its own.:)
17th February 2010, 06:47
keropi

this thread is awesome to the max :bowdown:
17th February 2010, 08:52
MagerValp

Quote:

Originally Posted by Zetr0

With this mod - you can poluate those spaces with 4 20 pin 256x4 DIP memory modules - Thus rendering the trapdoor interface - for the most part - redundant.

Just to clarify - if you solder in 44256 chips, you need to apply the same jumper mods to get 1 MB of chip? And should they be 80 ns?
17th February 2010, 10:29
Zetr0

@MagerValp

Yes, to solder chips in place on the motherbaord you will need to perform this modification for it to be seen as CHIP ram, you can use any 44256 20pin dip of 80ns or faster =D

This Mod changes the memory location of the 512KB trapdoor slot - which also linked to the 512KB sockets on the motherboard, it moves the location from (SLOW) FAST RAM (cannot remember the $address) to be inside the 1MB CHIP RAM pool
17th February 2010, 12:17
matt020

Quote:

Originally Posted by Zetr0

if you notice in the above picture, at the bottom of the board is the chip-memory - you will also notice that there are 4 unpopulated spaces -

With this mod - you can poluate those spaces with 4 20 pin 256x4 DIP memory modules - Thus rendering the trapdoor interface - for the most part - redundant.

Hmm this was raised in another thread... about adding chips to the empty space... and I dont beleive it was concluded on whether chips could be just dropped in, or if resisters, similar to the ones already on the board, were required to be added along with the additional chips... ?

---------- Post added at 20:17 ---------- Previous post was at 20:15 ----------

Quote:

Originally Posted by rkauer

Excellent tutorial, my friend!

I'm still looking for some spare time to dig a go on turning the trapdoor expansion into FAST RAM and using the spare spaces on the mobo to expand the chip RAM.

An humble A500 with 1Mb Chip & 0.5Mb (not so) FAST is a lovely machine on its own.:)

@Rkauer

Im confused. If adding chips to the empty motherboard memory slots along with performing this mod makes the trapdoor expansion slot redundant, how do you add the additional 0.5 mb after performing the 1mb chipram mod to total 1.5mb in an A500?
17th February 2010, 13:07
AndyLandy

Quote:

Originally Posted by matt020

Quote:

Originally Posted by Zetr0

if you notice in the above picture, at the bottom of the board is the chip-memory - you will also notice that there are 4 unpopulated spaces -

With this mod - you can poluate those spaces with 4 20 pin 256x4 DIP memory modules - Thus rendering the trapdoor interface - for the most part - redundant.

Hmm this was raised in another thread... about adding chips to the empty space... and I dont beleive it was concluded on whether chips could be just dropped in, or if resisters, similar to the ones already on the board, were required to be added along with the additional chips... ?

---------- Post added at 20:17 ---------- Previous post was at 20:15 ----------

Quote:

Originally Posted by rkauer

Excellent tutorial, my friend!

I'm still looking for some spare time to dig a go on turning the trapdoor expansion into FAST RAM and using the spare spaces on the mobo to expand the chip RAM.

An humble A500 with 1Mb Chip & 0.5Mb (not so) FAST is a lovely machine on its own.:)

@Rkauer

Im confused. If adding chips to the empty motherboard memory slots along with performing this mod makes the trapdoor expansion slot redundant, how do you add the additional 0.5 mb after performing the 1mb chipram mod to total 1.5mb in an A500?

I think you need an A500+ for that, or at least replace the Agnus chip on your A500 to one that supports 2MB. The normal A500 Agnus only supports up to 1MB ChipRAM.
17th February 2010, 15:04
rkauer

I'll make a thread when my analysis ends.

For now, munch this bit of information: the trapdoor have just a few address lines, plus 16 data lines and the clock lines.

Slow-fast RAM on Amiga is found by asserting the right address area. This is made by Gary, not Agnus. It is just a matter of cutting traces on the trapdoor connector and route them to Gary, maybe adding some delay lines to RAS/CAS.
17th February 2010, 17:08
tiffers

I did this mod, but I made it switchable, so that I could drop back to 512k CHIP + 512k SLOW RAM, for badly behaving programs.

The topmost pad of J2 actually peeled off the motherboard while I was doing it, so I had to follow the trace to another solder point to attach my switch wire.

It works well and I'm happy :)
27th April 2010, 00:06
Seaside

@Zetro the A500 magician.......

Questions

How can i populate 2mb of chip to the r6a mainboard ?

I have a spare 8375 and 8373 denise.

I mean after the mod and after soldering chips on the mainboard i should be able to use the BaseBoard expansion correctly ? Or the trapdoor signal pins are useless ?

Note that the BaseBoard has 2 options by jumpers

a)Set to Agnus
b)Set to Fatter Agnus.

When set to Agnus all the memory from the Bboard goes as fast.

When set to Fatter (and depending) the board and amount of memory goes as chip.

By factory default on my r6a mainboard the second option does not work.
But if i change the Agnus with 8375 and do the mods along with the soldering of chips i will have a total of 2mb chip on my r6a. Is that correct ?
27th April 2010, 00:20
rkauer

The problem is: Fatter Agnus (8375) is not pin-compatible with older Agnii.
27th April 2010, 00:23
Seaside

So r6a is limited to 1MEG Chip one way or another..............

Ok.........thanks rkauer :thumbsup:

The only way to do this is to find a 500 on a rev8 board. which has already 8375 on it and is pin compatible.
27th April 2010, 00:29
rkauer

Not true, either.

A guy made a 2Mb chip A500 rev6, check on Amiga.org. He gave the "recipe". It just require the address decoder, some cut & solder and the RAM chips.

Oh, and the 8372 Agnus (the PAL/NTSC "agnostic" one).
27th April 2010, 00:41
Zetr0

Quote:

Originally Posted by rkauer

The problem is: Fatter Agnus (8375) is not pin-compatible with older Agnii.

Indeed, the 8375 3190544-xx is pin incompatible with the with the other range of Agnii

heres some more research

Code:

8375 8372 8372B 8370 [390544-01] [A3000] pin# #desc #desc #desc #desc 01 DRD13 DRD13 DRD13 RD13 02 DRD12 DRD12 DRD12 RD12 03 DRD11 DRD11 DRD11 RD11 04 DRD10 DRD10 DRD10 RD10 05 DRD09 DRD09 DRD09 RD09 06 DRD08 DRD08 DRD08 RD08 07 DRD07 DRD07 DRD07 RD07 08 DRD06 DRD06 DRD06 RD06 09 DRD05 DRD05 DRD05 RD05 10 DRD04 DRD04 DRD04 RD04 11 DRD03 DRD03 DRD03 RD03 12 DRD02 DRD02 DRD02 RD02 13 DRD01 DRD01 DRD01 RD01 14 DRD00 DRD00 DRD00 RD00 15 +5V VCC VCC 16 _RESET _RESET _RESET _RESET 17 _INTR _INTR _INTR _INT3 18 DMAL _DMAL _DMAL _DMAL 19 _BLISS _BLISS _BLS _BLS 20 _BLIT _BLIT _BLIT _DBR 21 _WE _WE _WE _RRW 22 _RW _RW _RW _PRW 23 _REGEN _REGEN _REGEN _RGEN 24 _AS _AS _AS _AS 25 _RAMEN _RAMEN _RAMEN _RAMEN 26 RGA8 RGA8 RGA8 RGA8 27 RGA7 RGA7 RGA7 RGA7 28 RGA6 RGA6 RGA6 RGA6 29 RGA5 RGA5 RGA5 RGA5 30 RGA4 RGA4 RGA4 RGA4 31 RGA3 RGA3 RGA3 RGA3 32 RGA2 RGA2 RGA2 RGA2 33 RGA1 RGA1 RGA1 RGA1 34 28MHZ 28MHZ 28MHZ 28MHZ 35 A20 A20 A20 _XCLK (,A20) 36 _CDAC _XCLKEN NC _XCLKEN 37 7MHZ _CDAC _CDAC _CDAC 38 CCKQ _7MHZ _7MHZ _7MHZ 39 CCK _CCKQ _CCKQ _CCKQ 40 14MHZ CCK _CCK _CCK 41 TEST PAL/NTSC TEST 42 CRA0 VSS1 VSS VSS 43 CRA1 DRA0 DRA0 MA0 44 CRA2 DRA1 DRA1 MA1 45 CRA3 DRA2 DRA2 MA2 46 CRA4 DRA3 DRA3 MA3 47 CRA5 DRA4 DRA4 MA4 48 CRA6 DRA5 DRA5 MA5 49 CRA7 DRA6 DRA6 MA6 50 CRA8 DRA7 DRA7 MA7 51 _LDS DRA8 DRA8 MA8 52 _UDS _LDS _LDS _LDS 53 _CASL _UDS _UDS _UDS 54 _CASU _CASL _CASL _CASL 55 CRA9 _CASU _CASU _CASU 56 DRA9 DRA9 _RAS1 57 _RAS0 _RAS _RAS _RAS0 58 _RAS1 VSS2 VSS VSS 59 A19 A19 A19 A19 60 A01 A01 A01 A01 61 A02 A02 A02 A02 62 A03 A03 A03 A03 63 A04 A04 A04 A04 64 A05 A05 A05 A05 65 A06 A06 A06 A06 66 A07 A07 A07 A07 67 A08 A08 A08 A08 68 A09 A09 A09 A09 69 A10 A10 A10 A10 70 A11 A11 A11 A11 71 A12 A12 A12 A12 72 A13 A13 A13 A13 73 A14 A14 A14 A14 74 A15 A15 A15 A15 75 A16 A16 A16 A16 76 A17 A17 A17 A17 77 A18 A18 A18 A18 78 _LPEN _LPEN _LPEN _LP 79 _VSYNC _VSYNC _VSYNC _VSY 80 _CSYNC _CSYNC _CSYNC _CSY 81 _HSYNC _HSYNC _HSYNC _HSY 82 VSS VSS VSS 83 DRD15 DRD15 DRD15 DRD15 84 DRD14 DRD14 DRD14 DRD14 8375 SRC: A500 PLUS MAINTENANCE MANUAL 8372 SRC: "FATAGNUS PRESENT DANS LES AMIGA 300" .GIF 8372B SRC: "8372B-AGNUS_PIN.TXT" 8370 SRC: "8370-AGNUS-PLCC.PNG"

[CAUTION: 8372 SRC]
The schematic indicates a oblique pin plcc offset (see included picture)

http://www.guildserver.co.uk/data_im...tAgnus8372.gif

Now, I believe the 8375 318069-xx is a pin compatible replacement for the 8372B (the 8372B even has the 318069-xx written on it) - these chips are on the A600 rev 1.1 and above

Interestingly on the A600 rev 1.0 "June Bug A300" its different designation on the chip. 390xxx I will take some pics.

Anyway for the most part the 8375-318069-xx I have to confirm this with the A600 specification to be 100% sure if its a 100% drop in compatible, I would suggest everyone does the same.

Now dropping in an 8372B into an A500 Rev6a *should* give it the capacity to address 2MB of chip, you will need to do some MUXING of the RAS/CAS lines, so you will need a small *fast* IC.

however this does assume ALL the angus addressing lines are on the board.

A little while ago RKauer and TheCorfiot sent me some links with some awesome info on, I shall drag these up.
27th April 2010, 00:45
Seaside

Thanks Zetro. :thumbsup: :thumbsup: So i need 8372B. This is rare.

P.S. Please check your PM's here and there.
28th April 2010, 21:19
protek

Great tutorial Zetr0! :thumbup:

I used to have a rev 6A A500, which had this mod already applied. It was a nice surprise, when I turned it on for the first time and discovered the complete meg of chip mem. I then souped it up with a 2.05 kick rom and CFIDE68k.
26th May 2010, 01:57
Zetr0

Quote:

Originally Posted by protek

Great tutorial Zetr0! :thumbup:

I used to have a rev 6A A500, which had this mod already applied. It was a nice surprise, when I turned it on for the first time and discovered the complete meg of chip mem. I then souped it up with a 2.05 kick rom and CFIDE68k.

Thanks protek, maybe one day it may become a sticky =D

I would love to see some images with your Rev6a and the CFIDE setup - that would be great!
28th May 2010, 19:53
protek

Quote:

Originally Posted by Zetr0

Quote:

Originally Posted by protek

Great tutorial Zetr0! :thumbup:

I used to have a rev 6A A500, which had this mod already applied. It was a nice surprise, when I turned it on for the first time and discovered the complete meg of chip mem. I then souped it up with a 2.05 kick rom and CFIDE68k.

Thanks protek, maybe one day it may become a sticky =D

I would love to see some images with your Rev6a and the CFIDE setup - that would be great!

Here ya go:

First my old A500 with Mrmkl's CFIDE68k with 1 GB Kingston and WB 2.11. It doesn't show here but the CFIDE68k provides connection for an activity led, which I had glued in the A500's upper case. The kickstart is 2.05 (37.300). The mobo is rev 6A with 1 MB of chip (it maps the trapdoor memory as chip RAM). This particular A500 took some effort from me to get it working but it turned out pretty nicely. Unfortunately, I've passed it on to a new owner.

http://koti.mbnet.fi/tsaarela/TF/08102008049.jpg

Secondly, my A600 with Mrmkl's earlier CF IDE adapter, also fitted with 1 GB Kingston and OS 3.1 and 3.1 kickstart. Nowadays it has an A603 fitted. The Indivision ECS would be nice but I'm not that keen of removing the floppy.

http://koti.mbnet.fi/tsaarela/TF/21052008003.jpg
28th May 2010, 20:15
tokyoracer

This is the first time I have seen this tutorial and what can I say. Just WOW! Your skills ceace to amaze me Mr Z. :D

I'll have to employ you to fix all my broken Amiga's (your not 'that' far away) and pay you with tepid currys. Wachya' say? ;)
28th May 2010, 21:27
Tajmaster

Make sure the currys are "imported" from Yorkshire (preferably Bradford or my mums!) cos you southerners wouldnt know a decent curry if it hit you :D

Ive yet to find a good asian takeway place down here (Im in Potters Bar with the GF at the moment, the food sucks! lol)

And Zetr0 deservers a good curry, the mans a freakin genius :thumbsup::thumbsup::thumbsup: I did this mod on a friends A500 (McWilly aka Alison on here :) ) and it worked a treat, and simple and easy to do, thanks Zeet!
29th May 2010, 01:56
Zetr0

I absolutely LOVE curry!!

tonight my friends Winny and Yorkie came over and I cooked a chicken Jalfrezzi Masala with chipatties =) and Pilau rice... MmMmmMmmMmmmmmMMMmmm

yes... I make it meself... well the chipatties and chicken I bought, and I cheated a little bit with some jalfrezzi paste =D

but I am really liking this payment-by-curry method =D
29th June 2010, 17:04
TheoryBoy

Worked a treat.
http://amibay.com/picture.php?albumid=27&pictureid=209

http://amibay.com/picture.php?albumid=27&pictureid=208

Also solved my boot menu problem on 2.04 ks.
21st August 2010, 04:03
rkauer

As I am too lazy to flounder in my C= books, can someone confirm me the Agnus 8372A have two CAS lines, but only one RAS?

I think that's what stops using the A501 as 512kb slow-fast RAM...
_______________

Or, pondering what I'm pondering, can other brave soul swap the CASL to CASU lines on the trapdoor pins and run a wire from Gary's A21 pin to the cut-down JP7A? This will fool the Amiga to force the trapdoor memory to act as slow-Fast while the motherboard will have the full 1Mb chip RAM.
21st August 2010, 09:59
Zetr0

@TheoryBoy

Great Stuff :thumbsup:

@thread

Just to officially confirm, I have an 8375 - 318069-10 Agnus (2MB capable) Agnus working directly in my A2000 rev 6 (only 1MB at the moment though ;))

So this confirms its a "drop in" component for all the PLCC Agnii based machines (except A500+)

@rkauer

My friend, I do beleive the EXRAM signal (JP7A) from gary is used to bank the trapdoor port.

Because the onboard (unpopulated ram sockets) are tied to the trapdoor port to get the extra 512kb slow you would need assert a Garry Address and MultiPlex EXRAM (JP7A) for when Agnus is LOW.

Now I am pretty sure you are correct with the Agnus port not having enough RAS lines for a second 1MB - I also think that your ponder of swapping out the LCAS UCAS signals to the trapdoor port and a little A21 asert - you could get the 512KB, buuuuuut, if the lcas/ucas are not cut from the port (and then implemented with jumpwire this will cause issues with the existing 1MB of ram.

Hmmmm pondery ponders methinks =)
22nd August 2010, 23:57
rkauer

I was thinking hard on the matter last two days, and two things are known: the EXRAM signal from Gary is necessary to the Amiga know there is something hooked to the trapdoor connector, as then the Amiga puts that expansion in the slow RAM address. This is transparent to the system.

The device commonly have the same RAS & CAS lines as the Amiga chip RAM. Look in the slow RAM expansions: they all just use a multiplexer and two TTL buffers! So it's only a matter of redirecting the c00000 address to the expansion connector again after doing the 1Mb chip hack on the motherboard to have 512kb FAST RAM and activate it automagically!
23rd August 2010, 01:06
Zetr0

I like what I am reading...

I wonder how that would work though with the 8370 (half meg) Agnus?
24th August 2010, 00:04
rkauer

I think that will not work at all when using a 512kb-only Agnus. But since I have at least 3 8372A-equipped A500 here...
5th February 2011, 20:53
Zetr0

Update

because guildserver hosting is currently suspended - I have uploaded these images

The basic overview
http://s2.postimage.org/8o0x83w69/A500_6a_1_MBCHIP.png

JP2
http://s2.postimage.org/8o10j6l5t/jp2_zoom.jpg

JP7A
http://s2.postimage.org/8o0yvn8o1/jp7a_zoom.jpg
5th February 2011, 22:13
Tajmaster

Quote:

Originally Posted by Zetr0

Update

because guildserver hosting is currently suspended - I have uploaded these images

The basic overview
http://s2.postimage.org/8o0x83w69/A500_6a_1_MBCHIP.png

JP2
http://s2.postimage.org/8o10j6l5t/jp2_zoom.jpg

JP7A
http://s2.postimage.org/8o0yvn8o1/jp7a_zoom.jpg

I cant see the pics :blink:
5th February 2011, 23:30
scrappysphinx

no pics here either
6th February 2011, 08:16
Zetr0

how strange - I ca see them here =/

heres some thumb-links (click to zoom)

Modification Diagram
http://s2.postimage.org/1kt1shqjo/A500_6a_1_MBCHIP.png

JP7A
http://s2.postimage.org/1kt3g131g/jp7a_zoom.jpg

JP2
http://s2.postimage.org/1kt53kfj8/jp2_zoom.jpg

are these functioning okay?
6th February 2011, 08:22
jvdbossc

Yes they are, however the original postings "lost" every picture ;) I remember this thread with pictures.;) It was a nice hack-thread.:thumbsup:
6th February 2011, 08:31
Zetr0

Thanks my friend,

I do have the original pics somewhere, I will dig them up when I get time and upload them again.
6th February 2011, 09:59
Tajmaster

Quote:

Originally Posted by Zetr0

how strange - I ca see them here =/

heres some thumb-links (click to zoom)

Modification Diagram
http://s2.postimage.org/1kt1shqjo/A500_6a_1_MBCHIP.png

JP7A
http://s2.postimage.org/1kt3g131g/jp7a_zoom.jpg

JP2
http://s2.postimage.org/1kt53kfj8/jp2_zoom.jpg

are these functioning okay?

I can see these ones Zeets :thumbsup:
30th September 2011, 15:05
Fingerlickin_B

Got a Rev 5? JP2 re-jump is done as per Z-man's tutorial, BUT there is no JP7A.

No problem, just look at where the trapdoor expansion plugs in & cut a track as shown here:

http://www.amibay.com/picture.php?al...pictureid=1076

Obviously you'll need an 8372A Agnus for this to work ;)

PZ.
9th October 2011, 22:46
Zetr0

@Fingerz

I missed this update!! Great stuff!! :thumbsup:

A point to note though - an 8371 is also 1MB compatible for chip, its the 8370 thats only 0.5MB (512KB Chip only)
10th October 2011, 08:52
Fingerlickin_B

Good to know Z-money, thanks for the heads up! :D

PZ.
13th October 2011, 05:34
Matjam

Broken images :(

Suggest using imgur.com. Seems to be popular, no limits.
13th October 2011, 05:48
Fingerlickin_B

Quote:

Originally Posted by Matjam

Broken images :(

Suggest using imgur.com. Seems to be popular, no limits.

Do you mean mine, or Zetro's?

Some images won't show unless you are logged in (if you read this & only logged in to reply, you may have missed them).

PZ.
24th October 2011, 07:57
Fingerlickin_B

Hey Zetro, I have a question regarding the 8371 vs 8372A...

Can the 8371 *properly* address the RAM? I know it shows up, but does it really work properly?

I have a choice of both these Agnii & wondering if there really is any reason I should be using the 8372A?

*EDIT* - Guess I'll need the 8372A for ECS screenmodes once I install a Super Denise? 8372A it is then... :D

PZ.
18th April 2012, 18:45
Spaffy

I want to apply this hack adding the 512k from my old expansion to the spare seats on my rev6a but i have an ra5-2mb so dont want to render the trapdoor useless giving me 3mb of ram. I have the 8372a agnes too and the ra5 has a riser board that sits in the gary socket with the gary chip sat in that. The gary board is then linked to the trapdoor 2mb board via a cable.

Am i urinating in to a breeze or is this possible ?
Also due to the addressing of ram would my current setup be compatible with an external 8mb expansion in something like a supra ram ?

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