I want to take a Plus cartridge and solder a socket onto it so I can change the EPROM. It looks quite easy according to CPC Rulez (http://cpcrulez.fr/hardware_montage_DIP32_GX4000.htm) and CPC Mania (http://www.cpcmania.com/index.asp) (copying GX4000 cartridges).
However, I can't find out how these people above did it without worrying about the LK1 to LK6 bridges. It appears from the photographs that they left them all open, but on this website (http://www.vieuzordiland.fr/index.php?option=com_content&task=view&id=23&Itemid=34) the author says you have to set them differently according to the ROM you are using (if I understand correctly, the article is in French)...?
So does anyone know what I do?
No, you definitely need to set the correct LKs, otherwise it won't work. The CPCRulez picture where the Pang EPROM is intalled has LK1 and possibly LK6 (under the sticker) bridged, which must obviously be the correct positions for the EPROM they're using.
If you intend using lots of different types of EPROMs, you could put jumpers where the LKs are, but I would suggest just using one type of EPROM, the largest one possible and then set the LKs to suit it. That way you don't need to set anything ever and if the Game doesn't use the entire EPROM then who cares, the price difference between a 128k / 256k / 512k EPROM is minuscule.
Bryce.
Edit: A word of advice. If you try to remove the original EPROM in one piece, you'll probably create so much heat that you destroy the ACID chip in the process, unless you have a special head for your soldering iron to do this. The safest way to remove it, without causing damage to the ACID, is to cut all the legs first, remove the body of the EPROM and then de-solder each leg individually.
About LKs , you can find usefull informations there :
http://cpcwiki.eu/index.php/GX4000_cartridge (http://cpcwiki.eu/index.php/GX4000_cartridge)
http://pulkomandy.ath.cx/projects/ReACID/wiki/HardwareSchematics (http://pulkomandy.ath.cx/projects/ReACID/wiki/HardwareSchematics)
Quote from: Bryce on 19:35, 18 October 10
If you intend using lots of different types of EPROMs, you could put jumpers where the LKs are, but I would suggest just using one type of EPROM, the largest one possible and then set the LKs to suit it. That way you don't need to set anything ever and if the Game doesn't use the entire EPROM then who cares, the price difference between a 128k / 256k / 512k EPROM is minuscule.
Ah I see, the LKs determine the size of the EPROM being used.
Quote from: Bryce on 19:35, 18 October 10
Edit: A word of advice. If you try to remove the original EPROM in one piece, you'll probably create so much heat that you destroy the ACID chip in the process, unless you have a special head for your soldering iron to do this. The safest way to remove it, without causing damage to the ACID, is to cut all the legs first, remove the body of the EPROM and then de-solder each leg individually.
That's a great tip, thanks - I would definitely have done it the other way and wrecked the cartridge :)
Quote from: fano on 20:40, 18 October 10
About LKs , you can find usefull informations there :
http://cpcwiki.eu/index.php/GX4000_cartridge (http://cpcwiki.eu/index.php/GX4000_cartridge)
http://pulkomandy.ath.cx/projects/ReACID/wiki/HardwareSchematics (http://pulkomandy.ath.cx/projects/ReACID/wiki/HardwareSchematics)
Thanks Fano, I hadn't found these resources so far and they're very useful. So as far as I can see, most cartridges used 128k EPROMs and had LK1 and LK6 set. I can't find any 128k (or 256/512 either) on Google or eBay, they're all 1Mbit (128 x 8) versions which of course there isn't a LK setting for. Any ideas where I can get some compatible M27C1001s from...?
:( okay it's seems a bit more complicated than I though...
You can get the 27C1001 or equivalent (27C010) almost anywhere, here's where I get mine (€2.40):
http://www.reichelt.de/?ACTION=3;GROUP=A321;GROUPID=4510;ARTICLE=1911;SID=22vezn6tS4ARYAADKbObc6073d9b8a75f658e5ba1c07905e75c0b (http://www.reichelt.de/?ACTION=3;GROUP=A321;GROUPID=4510;ARTICLE=1911;SID=22vezn6tS4ARYAADKbObc6073d9b8a75f658e5ba1c07905e75c0b)
However, the Cartridge can evidently take ROMs up to 27C4001, which will give you a whole 512K (€4.25):
http://www.reichelt.de/?ACTION=3;GROUP=A321;GROUPID=4510;ARTICLE=1929;SID=22vezn6tS4ARYAADKbObc6073d9b8a75f658e5ba1c07905e75c0b (http://www.reichelt.de/?ACTION=3;GROUP=A321;GROUPID=4510;ARTICLE=1928;SID=22vezn6tS4ARYAADKbObc6073d9b8a75f658e5ba1c07905e75c0b)
I'd go for the 4001 with the LKs set permanently for that. A 128k program will still work on the larger chip with the rest of the space just left empty.
Just in case you're not used to buying EPROMs, the ones with OTP in their name means "One Time Programmable", make sure you don't order this type (for obvious reasons) by mistake :D
Bryce.
Quote from: Bryce on 10:55, 19 October 10
I'd go for the 4001 with the LKs set permanently for that. A 128k program will still work on the larger chip with the rest of the space just left empty.
That's cool, but why do they say 512kb * 8 ? I assumed this meant the capacity is 4096kb, does this not matter (i.e. the CPC only sees the first 512kb)?
Quote from: Bryce on 10:55, 19 October 10
Just in case you're not used to buying EPROMs, the ones with OTP in their name means "One Time Programmable", make sure you don't order this type (for obvious reasons) by mistake :D
Yes, I am still very new to this :) I thought making a custom cartridge would be a good next step for my electronics development and thankfully you've already helped stop me make two big mistakes...!
No, you're confusing bits with bytes.
EPROM part No.s usually refer to how many single BITS the chip can store, not BYTES. The 27C4001 stores 4096 bits, but because the chip has an 8 bit wide data bus, this is referred to as 8x 512k. The 512k is how many 8bit bytes the chip stores.
Another example, the 27C4002 can also store 4096 bits, but it has a 16bit Data bus, so this would be referred to as 16x256k.
So the CPC is using all 4096 bits, but it needs eight bits for each address.
Bryce.
So does anyone know if it's possible to use the extra space available on the EPROM (lets take 128kb as an example) to fill with other software or even existing ROMs with a Plus Cartridge?
For example, I know that you can get an image for BASIC and Parados to replace the BASIC/Burnin' Rubber ROM. But Parados just replaces the whole AMSDOS so this doesn't really answer my question...
Can the rest of the space be used for other stuff? So could you have BASIC, AMSDOS/Parados, Maxam, Protext etc etc in one cartridge? Or is this not possible?
If it is not possible, I guess the only other solution would be to use the wasted space used by AMSDOS (if I remember correctly it has a lot of CP/M Logo routines or something in there) in the same way Parados does and squeeze your own software into this space...?
Technically, there should be no problem putting Maxam, Protext or whatever in the extra space as long as you put each program at the start of a 16K block, but it won't be automatically activated like it normally would be on a simple ROMBoard. At start-up the CPC only probes ROMs 15 to 0 (in fact only 7 to 0 on the original 464). So the CPC won't know that Maxam is there because the cartridge ROMs are mapped to ROM 128 onwards. A simple routine or even a patched ROM 0 could change this though.
Bryce.
Quote from: Bryce on 14:29, 31 October 10
A simple routine or even a patched ROM 0 could change this though.
This is very interesting Bryce. Has anyone every actually attempted to do this?
I have finally managed to open my cartridge and the hairdryer trick did make it much easier and more malleable.
I have a Robocop 2 cartridge and none of the LKs are visably linked with solder. Vieuzordiland's website (http://www.vieuzordiland.fr/index.php?option=com_content&task=view&id=23&Itemid=34) says that Robocop 2 is a 512kb cartridge, but the ROM in mine is a M27C1001 (it also says -20XF1 after it) which I am sure is a 128kb? Also, the CPC Wiki (http://www.cpcwiki.eu/index.php/GX4000_cartridge) says that on some cartridges no LKs are linked but they are hardwired, and it has an example at the top of the pictures in the article - problem is, I can't tell on the picture or my cartridge how to see which are hardwired...?!
Anyone got any ideas as to what size ROM my cartridge has and what LKs are set?! I am going to buy some EPROMs for my burner and want to get the right ones so I don't have to mess about too much or run into problems thinking its not working as it's just because I got the LKs wrong.
Quote from: redbox on 19:23, 31 October 10
I have a Robocop 2 cartridge and none of the LKs are visably linked with solder. Vieuzordiland's website (http://www.vieuzordiland.fr/index.php?option=com_content&task=view&id=23&Itemid=34) says that Robocop 2 is a 512kb cartridge, but the ROM in mine is a M27C1001 (it also says -20XF1 after it) which I am sure is a 128kb?
This site also says it's not uncommon to have the same cartridge contents dumped several times in sequence into one image:
Quoteen réalité l'eprom est une 27C1001 donc 128ko maxi sur la cartouche. [...]
comparons une image trouvée sur le net et un dump propre à partir de l'eprom de la cartouche [...]
Ainsi dans la rom de 512k d'internet il y a juste 4 fois l'image du jeu (+ les flags cbxx [qui indiquent sans doute le changement de banque lors du dump. Cela va de cb00 à cb31]). [...]
Car la personne qui dumperai la cartouche sans démonter et dessouder l'eprom, c'est à dire en fabriquant par exemple un adaptateur cartouche pour brancher sur un lecteur eprom ou en dumpant par le biais du CPC+, se retrouverai alors par exemple avec un dump de 512K car les LK cablés sur la cartouche tromperait le hardware en donnant des adresses qui vont au delà de ce que gère l'eprom contenant le code original.
To make an attempt at approximately translating these excerpts for the less froggily inclined ;D (native speakers who'll hopefully approve of how this is conveyed to English will no doubt concede that starting even with its very own name and logo, that site has made misspelling into a form of art ;) ),
Quotethe EPROM actually is a 27C1001, hence a maximum of 128 kilobytes in the cartridge. [...]
Let's compare an image found on the Internet to a correct dump from the cartridge's EPROM. [...]
So the 512 kilobyte ROM from the Internet simply holds 4 times the image of the game (and the CBxx flags [telltale signs without a doubt of the bank switch during the dump. These go from CB00 through CB31]). [...]
This is because anyone going to dump the cartridge without disconnecting and desoldering the EPROM, i.e. by making e.g. a cartridge adapter to connect [it] to a EPROM reader or by dumping through a CPC+, would get for instance a 512 kilobyte dump as the LKs wired on the cartridge would mislead the hardware by yielding addresses that go beyond what is stored in the EPROM holding the original code.
Thank you for the translation, I can't always understand the French correctly.
So my Robocop 2 cartridge is 128kb but has the LKs wired as if it was a 512kb cartridge, which according to the wiki page (http://www.cpcwiki.eu/index.php/GX4000_cartridge) means that LK2, 4 and 6 are wired. This would suggest that you can actually use a 128kb (i.e. M27C1001) ROM and have the LKs are wired for 512kb it will still work?!
Also, I still can't see the 'hardwired' connections on the PCB even though I now should know which ones to look for :-[
Have you taken a look at the cartridge PCB pictures here (http://www.cpcwiki.eu/index.php/Mainboard_Versions#System_Cartridge_.28BIOS_of_CPC.2B.29_and_Game_Cartridges)?
Quote from: robcfg on 22:52, 31 October 10
Have you taken a look at the cartridge PCB pictures here (http://www.cpcwiki.eu/index.php/Mainboard_Versions#System_Cartridge_.28BIOS_of_CPC.2B.29_and_Game_Cartridges)?
Yes, but I still can't see where LK1 and LK6 are hardwired, for example on Board: 2700-023P-1.
And it doesn't tell me if I can use a M27C1001 (128kb) ROM when my cartridge has the LK settings for a 512kb ROM. The configuration for Robocop 2 would suggest that you can do this?
They're not soldered on bridges you should be looking for, they're part of the PCBs tracks. Have a look at the pictures below, I've highlighted the bridge tracks...
Bryce.
Thanks Bryce, I can see them now.
So my Robocopy 2 cartridge has LK1 and LK6 hardwired and is a M27C1001 128kb EPROM. It's definitely not the 512kb one that's mentioned elsewhere which is odd as it is an original.
I'm not going to mess with the LKs for now, I shall just order some 128kb EPROMs and see if I can get them working first!
So why would they do that? Copy protection mechanism?
I'm not 100% sure but I think the pinouts for the MC27... is the same regardless the capacity of the eprom so, in case of need, you could use a 512kb one if you don't have 128kb ones.
The capacity isn't directly what's important, the physical size of the IC is the reason the LKs are needed. A 128K EPROM has 28pins, the 1Mbit / 2Mbit ICs have 32pins. The shorter 28pin EPROM needs 5V on a pin that is used as an address pin on the 32pin IC, so the LKs are used to disconnect the address pin and connect it to the 5V line.
Bryce.
Edit: Here's the pinouts, as you can see if you start from the bottom, the pins are identical on both ICs, the larger IC just adds the new address lines, but shifts the 5V Vcc in the process. Pin 30 (NC) is A17 on larger EPROMs.
Quote from: Bryce on 21:56, 02 November 10
The capacity isn't directly what's important, the physical size of the IC is the reason the LKs are needed. A 128K EPROM has 28pins, the 1Mbit / 2Mbit ICs have 32pins. The shorter 28pin EPROM needs 5V on a pin that is used as an address pin on the 32pin IC, so the LKs are used to disconnect the address pin and connect it to the 5V line.
That makes sense (even to me) but doesn't explain why on the wiki page (http://www.cpcwiki.eu/index.php/GX4000_cartridge) it says that different LKs are needed for different capacity EPROMs even though these (128kb/256kb/512kb) all have 32 pins...?
I'm just glad my Robocop 2 is a 128kb ROM with LKs to match as I've been able to buy some cheap EPROMs on eBay. Can't wait for them to turn up.
The chart on the Wiki Page only shows what's 100% NEEDED, for example, LK4 on an 128K EPROM could be connected if you wanted, it wouldn't do any harm, but because the 27C1001 doesn't have an A17 you don't need to connect it.
With LK2 it's a little different, whereas most EPROMs have a PGM pin, the 27C4001 doesn't because it needs an A18 pin and they ran out of pins. The PGM pin gets pulled low to signify that the EPROM is to be programmed, but NEEDS to be held high otherwise. Because of this 27C4001 has a different programming sequence and if this pin was left connected to the CPCs A18 on a 27C1001 or 2001, the EPROM would keep switching to program mode (not a good thing).
Bryce.
So I finally have some time to have a go at making my custom EPROM cartridge (my second ever hardware project).
I bought a solder sucker, EPROM socket, EPROMs and EPROM programmer and have undertaken the first step of removing the Robocop 2 ROM and putting the socket into the PCB. It went better than I thought it would, but I did manage to break a PIN off the Robocop 2 ROM when removing it >:(
Now I have to program an EPROM to see if it worked (I was hoping just to put the old one in the socket for my first test) and am currently setting up my EPROM programmer.
Here are some pictures:
I wouldn't worry too much about breaking the pin off. If you de-soldered the entire EPROM pin for pin with the desoldering pump, then it has probably been internally damaged anyway.
Otherwise, it looks like you did a very neat job, hope it all works fine.
Bryce.
Well, I programmed an EPROM (when I found one that was actually blank - damn Chinese eBay sellers!).
And guess what. I doesn't work.
So I guess I'm going to have to check all the solder connections on my board?
Or have I fecked the ASIC like Bryce said I would? I only used a 12w soldering iron as per the CPC Rulez (http://cpcrulez.fr/hardware_montage_DIP32_GX4000.htm). But I didn't cut the legs of the original ROM (as they didn't either). :(
I get nothing on Plus boot-up, just black screen of the pink with lines that you get when ASIC doesn't connect.
::)
Quote from: redbox on 15:58, 16 November 10
Well, I programmed an EPROM (when I found one that was actually blank - damn Chinese eBay sellers!).
And guess what. I doesn't work.
So I guess I'm going to have to check all the solder connections on my board?
Or have I fecked the ASIC like Bryce said I would? I only used a 12w soldering iron as per the CPC Rulez (http://cpcrulez.fr/hardware_montage_DIP32_GX4000.htm). But I didn't cut the legs of the original ROM (as they didn't either). :(
I get nothing on Plus boot-up, just black screen of the pink with lines that you get when ASIC doesn't connect.
::)
I think Bryce meant the eprom.
But I think you are worried about the ACID?
Well, difficult to know what's happened.
Oh, that doesn't sound good. Are you sure that the image you burnt to the EPROM was a good one (with the header removed etc) and did you verify that it was properly burnt to the EPROM? These would also cause the CPC to react that way.
If all is OK with the EPROM, then you probably have fried the ACID chip, which would be rather annoying.
The 12W specification of the Iron isn't really the important factor, the temperature of the iron is very importantant and also, that you don't hold it on any pin for more than around 2-3 seconds. Too hot or too long will definitely destroy any IC.
Bryce.
Edit: @Arnoldemu, It was the ACID that I cautioned he might destroy, which is why I suggested cutting the EPROM off to reduce the time required for de-soldering.
Quote from: Bryce on 16:27, 16 November 10
Oh, that doesn't sound good. Are you sure that the image you burnt to the EPROM was a good one (with the header removed etc) and did you verify that it was properly burnt to the EPROM? These would also cause the CPC to react that way.
Yes, I tried the AMSDOS/ParaDOS image and the Switchblade one. I converted both from CPR to BIN using CPR Tools (http://www.cpcmania.com/). I then programmed them and verified them using the programmer and all came up ok.
Quote from: Bryce on 16:27, 16 November 10
If all is OK with the EPROM, then you probably have fried the ACID chip, which would be rather annoying.
Sh*****************t! I did try to have the iron on the pin for as little time as possible, but I did muck it up a couple of times, so maybe that's when it happened. I will have to get another one.
Quote from: Bryce on 16:27, 16 November 10
It was the ACID that I cautioned he might destroy, which is why I suggested cutting the EPROM off to reduce the time required for de-soldering.
I'm not worried about destroying the ROM, just the ACID. I thought you suggested cutting the ROM legs so that I didn't conduct heat through the circuit and up to the ASIC, or am I getting this wrong? Is it just so I can get it out quicker?
I assume you mean the ACID when you say ASIC (the ASIC is in the CPC so it shouldn't be effected). The reason for cutting the EPROM off is so that each pin can be removed very quickly and the heat doesn't spread over to the ACID through the PCB tracks. If you try to get the EPROM out in on go, then you have to put the iron on each pin several times, which will most likely destroy the ACID from the excessive heat. Which I think you've just found out :(
Bryce.
Quote from: Bryce on 17:23, 16 November 10
I assume you mean the ACID when you say ASIC (the ASIC is in the CPC so it shouldn't be effected). The reason for cutting the EPROM off is so that each pin can be removed very quickly and the heat doesn't spread over to the ACID through the PCB tracks. If you try to get the EPROM out in on go, then you have to put the iron on each pin several times, which will most likely destroy the ACID from the excessive heat. Which I think you've just found out :(
Thanks for the explanation Bryce and I know I should have listened to you in the first place! I also watched some YouTube videos about doing similar things and they all cut the chip legs first like you suggested.
The reason I tried to get the ROM out whole is because I wanted to put it straight back into the socket to check it as I didn't have the programmer setup when I started (but I put paid to that myself by breaking a pin on it anyway) and also because I saw they'd done it on CPC Rulez - I expect that they did it a lot quicker and are much more experienced than me though.
Anyway, I'll get another cartridge and try again. The Willem EPROM programmer is really good btw and I would love to make some stuff with it in the future - hardware is cool!
I had a thought about the custom EPROM cartridge: wouldn't it be good it there was a cartridge extension cable with an edge connector (to plug into the Plus) linked to a socket on the other end that you plugged the cartridge into. This would mean that on the cartridge you could use a ZIF socket (which you can't on a normal plug straight in cartridge because of the height restriction) and rest it on top of the Plus. I saw the same blue ZIF that's in my Willem on eBay for a couple of quid and if you combine this with one of the IC sockets I'm trying to solder in it gives you the clearance you need over the ACID to put it straight on top... What do you think? Or is it hard to get the edge connectors wired up etc?
No, now that I have a plus too, I was thinking of doing something similar, but my plan was to make a card with 1 ACID but 4 normal Sockets and a Dip-switch to choose which ROM is activated. That way I can have my 4 favourite titles on hand without having to do much IC switching. The only slightly difficult bit is that it has to be a double-sided PCB.
Bryce.
Well, for one of the four sockets you should use a Textool-socket, since the "favorite" ROM can change after some time ;-)
A Texttool / ZIF socket is a very expensive part (€11.70 for 1 = €46.80 for 4!!!) just to swap the EPROMs occassionally. On an EPROM burner they make sense, but not on a Multi-cartridge system.
Bryce.
Quote from: Bryce on 09:03, 19 November 10
A Texttool / ZIF socket is a very expensive part (€11.70 for 1 = €46.80 for 4!!!) just to swap the EPROMs occassionally. On an EPROM burner they make sense, but not on a Multi-cartridge system.
Bryce.
Fair enought. I was just thinking how it would be in my case. I would burn my four favorites, but after using them a while .... well, you long for something new then.
Right, thery are expensive. But one of them probably could make sense :-) Imagine you meet a friend of go to a CPC meeting and you intend to show somebody the 20 Plus games that you have on EPROM ;-) I mean ... come on ... one textool equals three beers ;-)
Quote from: Bryce on 09:03, 19 November 10
A Texttool / ZIF socket is a very expensive part (€11.70 for 1 = €46.80 for 4!!!) just to swap the EPROMs occassionally. On an EPROM burner they make sense, but not on a Multi-cartridge system.
There are ZIF sockets on eBay (http://cgi.ebay.co.uk/32-Pin-Universal-ZIF-DIF-IC-Test-Board-Tester-Socket-/110589673229?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item19bfa87f0d) for £3.50. I hope to use one on my cartridge when I stop frying ACIDs :(
Got my new cart today to try again. So I am guessing I should cut the legs first (looks difficult as the ROM is low in the PCB with not much leg exposed - any ideas?) and then desolder/pump really quickly (under 2-3 seconds per pin), put IC socket in then re-solder really quickly... is this right?
Cut the legs as close to the chips body as possible so that the remaining pins are as long as possible. When the chip has been completely cut free, mount the PCB in a vice or PCB holder. To remove the pins, grip them on the chip side with a small pliers, apply the soldering iron and pull the pin with the pliers at the same time. This way you should only need to apply the soldering iron for a second or less and nothing should get damaged.
If you want to be really really sure, you could add a binder clip (like this one: http://www.istockphoto.com/file_thumbview_approve/420111/2/istockphoto_420111-binder-clip.jpg ) on top of the ACID pins to absorb any heat that does make it to the ACID.
Bryce.
Great tips Bryce, thank you, will be sure to do that this time.
When I remove the old solder left after removing the ROM, should I just be really quick again with the soldering iron and pump?
And when I solder the IC socket back onto the PCB, I'm assuming be really quick again? And what size solder would you recommend...?
Exactly, always make sure the heat is there for the minimum amount of time and pause between pins to give it time to cool back down. The exact solder size isn't all that important as long as it's not way too large. I normally use a 0.75mm solder - Leaded! Because this whole ROHS thing is a joke and CPCs weren't ROHS to start with anyway.
Bryce.
I have started with another cartridge and taken all the precautions this time...!
But I have come across another problem: on the pin holes where I have removed all the solder, when I try to resolder the IC socket pins, the solder won't stick. It only sticks on the pin holes where some of the old solder remains for it to join to.
I bought a flux pen and tried applying that but the solder still won't stick. Any ideas?
Either it's not getting hot enough (ie: the iron is touching the pin but not the pad) or it's a problem due to trying to mix unleaded and leaded solder.
Bryce.
Ah I see, my solder is lead-free and I'm guessing the 1990s Amstrad solder is leaded...
Maplin didn't have any lead solder. Probably some bullsh*t EU law about that!
Will get the iron hot and make sure I'm touching the base and report back.
It won't solder because the metal circle at the pinhole on the PCB I want to solder is missing.
I think it became removed when I unsoldered the pins. So all that is left is the PCB board which the solder won't stick too.
>:(
No, problem, depending which pin it is, you can either scratch the solder-mask off the track and solder a piece of wire to the pin and track to bridge the gap (if the track only goes to the edge connector) or if it's a pin that goes to a different component, then solder a wire bridge to the next solder point.
Bryce.
Looks a bit difficult (for a hardware n00b like me) as it's a double-sided PCB but will give it a try!
I think I might have pulled the metal circles at the pinholes (solder point?) off when removing the ROM legs that might not have been completely unsoldered, will have to be more careful (again).
I got another (!) cart, took all the precautions (including bulldog clip on the ACID) and... it seems to have worked.
Only slight snag is the only EPROM I have blown is a borked copy of the normal Plus cartridge, but I think it was enough to prove the ACID is working.
Thanks for all your help Bryce, really appreciated. I will be back here when it breaks ;)
I now need my EPROM eraser to turn up so I can get some proper software on there!
Congratulations. Pity you had to destroy some good ones to get there, but it's all experience gained and any future mods will be done with more confidence and hopefully success on the first attempt.
Bryce.
Quote from: Bryce on 16:54, 24 November 10
Congratulations. Pity you had to destroy some good ones to get there, but it's all experience gained and any future mods will be done with more confidence and hopefully success on the first attempt.
Bryce.
talking about destroying cartridges.
I have two cartridges, both have EPROMs. Both didn't work to well so I stored them in a box along with other electronics (z80's, old 3" disc drive motors).
Have I damaged them by storing them with the motors? And have I damaged the other stuff in the box?
Anyway, I tried them out. One turns the screen black like it tries to execute something but the rom is blank, the other shows some corrupted lines and the usual pink/purple background, like it tried to initialise the crtc and failed.
So are they stuffed, or could they be reprogrammed to work?
(I wish I had an eprom eraser and programmer btw - perhaps it is time to invest in one)
Is there any way I could tell if the acid is responding by putting a basic multimeter on one or more pins or similar?
I would like to repair them if possible, or at least re-use them for a future project.
Well, you can replace the EPROM by a socket, then get a burned new EPROM and see it it works.
Other than obvious physical damage, there are only two things that can damage the cartridge PCB:
1) Strong UV light (direct sunlight is enough) can and will delete or corrupt the program on the EPROM.
2) A static electrical dis-charge could damage either the EPROM or the ACID permanently.
Magnetism (from the motors magnets) has no effect on either of the ICs. There are other factors however, that could cause the cartridge to malfuntion. Oxidised contacts will cause crashes / non-starts and is very easy to solve, you just need to clean the edge connection. Slightly more difficult are dry joints. This is when a crack appears in the solder joint. Under a microscope they are obvious but not always visible with just the naked eye.
If you're not sure and afraid you'll only damage them worse, send me them and I can check them out.
Bryce.
Quote from: arnoldemu on 21:39, 30 November 10
Anyway, I tried them out. One turns the screen black like it tries to execute something but the rom is blank, the other shows some corrupted lines and the usual pink/purple background, like it tried to initialise the crtc and failed.
These are exactly the kind of things I was seeing with my attempts at customising the cartridges with EPROMs.
After speaking to Bryce, I'm hopeful that it's just oxidised contacts or dry joints (my dodgy soldering!) and that the ACID isn't fried.
Quote from: arnoldemu on 21:39, 30 November 10
I wish I had an eprom eraser and programmer btw - perhaps it is time to invest in one
If you want some EPROMs programmed to test your boards, PM me and I'll send you a couple.
reflote :) .
I bought a top 853. I don't have (at the moment) m27c1001. But I remember i conserve and old chip bios from my old pentium 200 mmx.
So I rescue them from a old box and put it in the programmer to test it.
My surprise is the chip is flash 128k x 8, but with a little diferent requeriments in the pin supply.
Is posible this chip can work in the gx4000/plus.?
http://pdf.datasheetcatalog.com/datasheet/macronix/MX28F1000PRC-90C4.pdf (http://pdf.datasheetcatalog.com/datasheet/macronix/MX28F1000PRC-90C4.pdf)
http://pdf.datasheetcatalog.com/datasheet/stmicroelectronics/2380.pdf (http://pdf.datasheetcatalog.com/datasheet/stmicroelectronics/2380.pdf)
In the table The chip need high voltage in we (p in m27c1001) in read mode, but the m27c1001 work with the two states.
But in the cartridge(i not sure) pin 31 is connected to vcc permanently?
This chip will work fine in a standard cartridge if the links have been set correctly.
Bryce.
Thank you.
And 29C010?
I ask, becasue i can buy this memory localy. I can buy a m27c1001, but if i buy the m27, i need buy an eeprom eraser to china.
http://www.diotronic.com/semiconductores/memorias/flash/memoria-128kx8-dip32-flash_r_56_12068.aspx (http://www.diotronic.com/semiconductores/memorias/flash/memoria-128kx8-dip32-flash_r_56_12068.aspx)
PD the links default is the burning rubber links
I think the 29C010 has the same pinout as the 27C1001 (you'd have to check the datasheet), so it should be fine. Only the 512K Flash/EEPROM has a different pinout to its EPROM equivalent.
Bryce.
Finally i bought 29f010, and it works perfect. The chip from pentium bios also work o.k. Unfortunly, the original gx4000 power supply broken ??? and the pentium chip bios die with it wtf.(gx4000 an acid is o.k).
I have extracted the eprom from cartridge withouth hot issues in the acid, i used this: www.youtube.com/watch?v=mv4uFaX3UbI (http://www.youtube.com/watch?v=mv4uFaX3UbI#ws)
Works perfect, after finish, acid is cold and i can extract and recicle the eprom.
I found rick dangeorous and beyond of ice palace(cartridge from cpc power) not work in gx400 and amstrad classics is unusable(no keyboard in gx4000).
Quote from: dragon on 11:38, 17 November 13
I found rick dangeorous and beyond of ice palace(cartridge from cpc power) not work in gx400 and amstrad classics is unusable(no keyboard in gx4000).
Many of these "homebrew" or cartridge "hacks" have not been tested on gx4000 and never modified to work with joystick.
I took a lot of time to make the Stryker cart work on gx4000.
Quote from: arnoldemu on 10:30, 18 November 13
Many of these "homebrew" or cartridge "hacks" have not been tested on gx4000 and never modified to work with joystick.
I took a lot of time to make the Stryker cart work on gx4000.
Thats why mark it as gx4000 games in cpcpower has no sense :).
great work in stryker cart. The other big game fault in gx4000 is prehistorik 2 maybe with no$scart.