15 replies to this topic

[GuybrushThreepwood]

Hello to everyone! I've found a genuine copy of Fat Bobby from Telegames but unfortunately the game hangs on the startup screen or, to be more precise, it seems that it hangs after a period of time... If I leave it at the startup screen then after some seconds I can't even have a reaction to any key press while if I press A immediately after the startup screen shows up then it goes to a black screen like it's starting the game but it hangs there.
Usually this kind of issues is due to dirty or oxidized cartridge contacts but unfortunately this isn't the case. I fear that the eprom could be corrupted. Is there anything that I could try? Has someone of you experienced the same issue with this or other games written on third party carts?
I'm confident that under the white stickers there is an eprom and I'm tempted to check it out but this would mean ruining the cart for collection purposes and I'd like to have some advices before...
Having found quite a rare game that seems unfortunately broken is a pity. I've found it in a lot (the Lynx and all the other games in the lot are working) so I have paid it more or less nothing but this doesn't meant that I don't like to sort this out.
Thanks to everyone for your replies!

[Havok69]

You're probably out of luck unless you have access to the ROM and an eprom burner. However, I would go over the contacts once more to see if that helps. Usually a good old fashion pencil eraser works wonders on those contacts.

Good luck!

[karri]

GuybrushThreepwood, on Wed Jan 19, 2011 4:35 AM, said:

I fear that the eprom could be corrupted. Is there anything that I could try?

The only way to find out bit-rot on an EEPROM would be to make a dump of the cart and compare the dump to a known good cart or a known MD5 sum.

The MD5 sum of Fat Bobby should be 69abd21c83390dae54630919c3c150d0

If you have a flash-cart it would not be difficult to make a small MD5 calculator that you load in RAM, then insert the cart to examine and press a key to make a MD5 sum of the inserted cart.

If the "wrong" bits are ones you can just try to re-program the chip. If the wrong bits are zeros you need to erase the chip using UV light first.

--
Karri

[GuybrushThreepwood]

Thanks for your replies! Unfortunately, the contacts aren't the culprits for sure: I've already done every effort to exclude that kind of issue though I was already confident that they were fine as they looked clean and shiny.
For what concerns what karri has said, everyhing is very interesting (I'd really like to thank him for his advices) but I fear that these kind of things are beyond my knowledge... First of all, I don't have a flash cart nor I'm able to program an MD5 calculator for the Lynx nor anything else. Apart from this, I think that the only available alternative to make a dump of the cart is desoldering (if possible) the eeprom (I've missed an 'e' in my previous post! ) and mounting it inside an eeprom burner and I can't do that neither because I haven't an eeprom burner.
I fear that I'm out of luck... Is there anything else that I could try? I don't believe it...

Edited by GuybrushThreepwood, Thu Jan 20, 2011 3:46 PM.

[karri]

GuybrushThreepwood, on Thu Jan 20, 2011 3:44 PM, said:

Thanks for your replies! Unfortunately, the contacts aren't the culprits for sure: I've already done every effort to exclude that kind of issue though I was already confident that they were fine as they looked clean and shiny.
For what concerns what karri has said, everyhing is very interesting (I'd really like to thank him for his advices) but I fear that these kind of things are beyond my knowledge... First of all, I don't have a flash cart nor I'm able to program an MD5 calculator for the Lynx nor anything else. Apart from this, I think that the only available alternative to make a dump of the cart is desoldering (if possible) the eeprom (I've missed an 'e' in my previous post! ) and mounting it inside an eeprom burner and I can't do that neither because I haven't an eeprom burner.
I fear that I'm out of luck... Is there anything else that I could try? I don't believe it...

There are two probable things that could have happened:
- bit rot = some bits get weak and change state
- cold solders = some pins on the cart are not properly connected

Fixes:
- re-program the chip. Needs a burner with some special clip to put over the chip.
- replace the chip
- re-solder all connections

One trick that is really amazing is to heat up broken electronics to 190 °C (370 °F) for 10 seconds. I have fixed completely broken motherboards, pci-cards and switches using just a heat-gun. The trick is not to over-heat or under-heat. You could also try an owen.

Making a dump of your cart is not really interesting as the image is available on the net. But the MD5 sum makes sense. The flash cart is the easiest way but there is also another tool called the BLL downloader that can do the trick.

If you are a little adventurous I can send you instructions of how to modify your Lynx so that you can change carts while the Lynx is powered up. The next thing is to get some game with a downloader on it (S.I.M.I.S. Championship Rally, Megapak perhaps some others too). You also need a download cable. I think Wookie just created an USB-based download cable.

Creating a small downloadable MD5 calculator would not be too difficult. I can help with that one.

Of course a bad MD5 sum will just verify that the ROM is bad. It won't fix it.

--
Regards,

Karri

Edited by karri, Fri Jan 21, 2011 12:13 AM.

[GuybrushThreepwood]

You're really tempting me... All of these things are very very interesting! I own Championship Rally and I'm ready to modify my Lynx to make possible the carts hot swap too but I'd like to be sure that I'm not going to take any risk of broking Championship Rally or my Lynx.
In the meantime, I will make a search about Wookie's download cable... Thanks for everything!

Edited by GuybrushThreepwood, Fri Jan 21, 2011 4:00 AM.

[GuybrushThreepwood]

I've found the Wookie adapter you're speaking of

http://www.classicga...blynx_board.png

but I have no way of obtaining a pcb like that so I fear that I would be forced to look for something simpler, even with serial or parallel connection. I would search on the forum.
Apart from that, I'm still waiting for some advices from you, karri. Thanks for your help and have a good day!

Edited by GuybrushThreepwood, Sun Jan 23, 2011 5:28 AM.

[GuybrushThreepwood]

I've done some digging around and I think that I've found almost everything that I need (even more than that, a lot of very interesting stuff: sad to have not enoguh time):

http://www.atariage...._1#entry1261237

http://www.monlynx.de/lynx/bll.html

http://www.monlynx.de/lynx/tools.html

http://www.atariage...._serial comlynx

Now I need to find the time to sum things up...

Edited by GuybrushThreepwood, Sun Jan 23, 2011 12:27 PM.

[karri]

This data is a little outdated.

I try to update the modification needed into Disable cart detection

And I also have a link to a site that sells USB-proto boards that can be used to connect to the Lynx directly. I believe the price used to be $15 or so.

I have been using this ftdi-board myself for years now.
--
Karri

[GuybrushThreepwood]

Hi and thanks for your reply! The modification needed to disable cart detection is very simple and I will do it ASAP. For what concerns the adapter needed to connect to the Lynx, please send me all the links and/or pinouts that you think may be necessary. I can't succeed in finding my comlynx cable anymore so it's better if possible to have a solution with a built-in jack to connect directly to the Lynx otherwise I would buy another comlynx cable. Have a good day!

[karri]

GuybrushThreepwood, on Tue Jan 25, 2011 6:25 AM, said:

Hi and thanks for your reply! The modification needed to disable cart detection is very simple and I will do it ASAP. For what concerns the adapter needed to connect to the Lynx, please send me all the links and/or pinouts that you think may be necessary. I can't succeed in finding my comlynx cable anymore so it's better if possible to have a solution with a built-in jack to connect directly to the Lynx otherwise I would buy another comlynx cable. Have a good day!

I did some surfing and found a really nice cable that seems to support the Lynx non-standard baud rates.

Have a look at ftdi cables


All the electronics is inside the USB connector

The price is not bad. £16 for a single cable. If you order one choose a +5V version without a connector.

The ComLynx connector is a 2.5mm stereo one. Leave the tip unconnected, connect TxD and RxD together to the middle ring and connect GND to the outmost ring.

You need my Mttty.exe application for downloader to work. My server is mostly crashed now. I try to find a new spot for my uploads.

I also committed a new BLL-configuration template to the cc65 compiler maintainer. The idea is to be able to create downloadable applications simply by adding "-C lynx-bll.cfg" to the command line of the linker command.

cl65 -C lynx-bll.cfg -o md5.com $(OOBJECTS) lynx.lib

If you rather build a cart you can use the standard config file like:

cl65 -C lynx.cfg -o md5.lnx $(OOBJECTS) lynx.lib

or you can leave it out and just specify the target to be a Lynx like:

cl65 -t lynx -o md5.lnx $(OOBJECTS) lynx.lib

Well. I still need to write the MD5 application.

--
Regards,

Karri

Edited by karri, Wed Jan 26, 2011 1:38 AM.

[GuybrushThreepwood]

Hi and thanks for your detailed reply. Could the Silabs CP2102 bridge be fine or not?

http://www.silabs.co...Docs/cp2102.pdf

If I remember well, I should have a cable based on that somewhere...

[karri]

GuybrushThreepwood, on Wed Jan 26, 2011 9:50 AM, said:

Hi and thanks for your detailed reply. Could the Silabs CP2102 bridge be fine or not?

http://www.silabs.co...Docs/cp2102.pdf

If I remember well, I should have a cable based on that somewhere...

The device does not support baudrates 62500 or 31250 by default. In the application note 205 there is enough information for re-compiling the dll to support also these Lynx-specific baud rates.

But you can always set for 9600 baud which is available. Or do the extra work to get 62500 and 31250 working.

--
Karri

[rdemming]

karri, on Wed Jan 26, 2011 1:05 AM, said:

I did some surfing and found a really nice cable that seems to support the Lynx non-standard baud rates.

Have a look at ftdi cables

All the electronics is inside the USB connector

The price is not bad. £16 for a single cable. If you order one choose a +5V version without a connector.

Indeed really nice solution. Especially the version with transparent connector so you see the electronics inside. But as an EU citizen, I have to pay tax and shipping, making it a total of 27.84 pound (about $44).

So instead I ordered ]this one eBay Auction -- Item Number: 360322100125 for $15 which uses the same chip (FT232RL). Maybe not as nice as the cable, but it only costs 1/3 including shipping and USB cable.
This chip also supports an unique serial number and storage of custom data in the internal EEPROM accessible over USB. Might be fun to play with that too although not much of use with the Lynx as the EEPROM seems not accessible from the serial end.

Robert

[karri]

rdemming, on Thu Jan 27, 2011 3:22 AM, said:

Indeed really nice solution. Especially the version with transparent connector so you see the electronics inside. But as an EU citizen, I have to pay tax and shipping, making it a total of 27.84 pound (about $44).

So instead I ordered ]this one eBay Auction -- Item Number: 360322100125 for $15 which uses the same chip (FT232RL). Maybe not as nice as the cable, but it only costs 1/3 including shipping and USB cable.
This chip also supports an unique serial number and storage of custom data in the internal EEPROM accessible over USB. Might be fun to play with that too although not much of use with the Lynx as the EEPROM seems not accessible from the serial end.

Robert

I have an application that can pass data at all Lynx speeds. As my own server is pretty much useless at the moment I put it in Ubuntu One for download. Mttty.exe

In Windows it should work by installing the ftdi drivers. In Linux it works under Wine directly. But of course you must add the com1 device manually.

Do it from the shell:

  cd .wine/dosdevices
  ln -s /dev/ttyUSB0 com1

You may also have to give user rights to it.

  sudo chmod a+rw /dev/ttyUSB0

--
Regards,

Karri

[GuybrushThreepwood]

After four months I've finally found some time to work on the issue with Fat Bobby. First of all, I need to say a great thank you to karri: he has helped me a lot and now I have all the necessary.

• I've modified my Lynx to disable cart detection
  
• I've bought a suitable serial interface and a comlynx cable
  
• I've built an adapter to connect everything to the Lynx following karri's advices in one of the previous posts

I've tried to use mtty following all the advices that karri has kindly told me in private (mainly about how to set up the port for the connection: 9600, 8 bit, space parity, 2 stop bits, No Reading tick mark took away).
By what I've understood, the loader built into championship rally should sense the connected interface by a magic cookie sent on the comlynx line and exit the game in favour of the loader then I should be able to send the dumper to the lynx by mtty but CHR starts normally and the loader doesn't take the control.
The comlynx cable is new and fine, the interface has the right specs and my adapter is ok (apart from the fact that it's so easy to be impossible that there are issues with it, I've checked it with a multimeter and everything's fine).
Do I fail at some point?

Edited by GuybrushThreepwood, Fri May 27, 2011 3:56 AM.