Calendar error & UniBIOS

Hey Razoola & others,

I've got Dimitri1983's board over here and fixed the memory error... but now it's coming up with the dreaded CALENDAR ERROR message.

It's not the D7990 clock/calendar chip, the 74HC32, or any of the traces between them. The battery has been charged up and I've flipped the dipswitches to do the Backup RAM test and flipped 'em back with the same result. I think it may be either the NEO-FO chip or a trace leading to it.

Is this something that the UniBIOS will help with? If so, is there anyone near Dallas that can burn one (or more) for me? I have plenty of the EPROMs for it - I think I have around 40 of 'em in the bins.

Thanks,

Raymond

The unibios can skip this error yes and you can get the latest version from the unibios homepage (link in my sig).

Raz

channelmaniac said:

I think it may be either the NEO-FO chip or a trace leading to it.

Click to expand...

Maybe this little scheme is of help:

http://img81.imageshack.us/img81/5886/2slotcalendarak9.jpg

BTW, I found that you get a calendar error also if you set the jumper above the 5814 vram chips (on a 2-slot) that's connected to a pin of the LSPC2 that on home systems controls the refresh rate (low 60Hz, high 50Hz). It would seem that on MVS hardware the 50Hz refresh is in conflict with the calendar clock (absent on AES)? Raz, do you think that skipping that calendar error with the unibios you can run the system at 50Hz?

Thanks MKL,

Do you happen to know which pin on the LSPC2 the jumper connects to?

I already found a copy of that schematic but had already pinned out all the connections by comparing this board to my 1 slot.

I figure it has to be a corroded plate through somewhere on the board. That was the cause of the video RAM issue and I found that one. The board had quite a bit of rodent mess on it but cleaned up pretty well. I had to replace the BIOS socket as it was gunked up and clean up some corrosion on the pins of the BIOS chip as well.

I don't have a UNIBIOS here so was hoping someone in Dallas could burn me one. I have 2 EPROM programmers - a TOP-2004 eBay special and a Data I/O Series 22 for doing old old EPROMs and those old assed 16 to 24 pin bipolar PROMs from the ancient machines - but neither of them do 16-bit chips.

Razoola - Are there any other tests the system does after the "calendar" test? I'd hate to spend a few more hours troubleshooting and fixing the issue just to find there is another error message popping up. Can you list out the order in which the tests are run?

Thanks!

RJ

channelmaniac said:

Do you happen to know which pin on the LSPC2 the jumper connects to?

Click to expand...

It's pin 64 and I've just checked that with the unibios it runs fine at 50Hz. Probably not a useful feature considering practically all PAL TVs today can handle 60Hz but it could be fun to see an MVS run at 50Hz, especially in a cab...

Hmmm... That's not it. Pin 64 goes straight to a pad that is for a non-existant resistor. Same on a known working board.

I pinned out the whole NEO-F0 chip and am reverse engineering some of the schematic... There are some strange connections to that chip... A4 through A7 from the CPU connect to it... but not A1 to A3... etc...

From memory after the calender check there is the memory card check (if a card is inserted and non formatted) and the z80 communication check.

Raz

Raz,

What can you tell me about the watchdog settings and the boot sequence for the Neo Geo?

On my 1 slot it boots to the crosshatch without a cartridge installed. On this board with the CALENDAR ERROR message it has the watchdog circuit firing and "click click click.... to infinity coming from the speakers.

I have a feeling that if I can figure out where that problem is, then the board will work fine. I'm suspecting the NEO-F0 chip is bad though...

RJ

Im not sure what I can actually tell you what will be helpfull. The watchdog port must be written to every so often or the NeoGeo will reset itsself. With or without a cart the system should still be doing the calander check so if its failing to give an error with no cart that is very strange. The cart check (wether to start splash screen or crosshatch) only happens after the system checks are complete.

From memory it is possible from what I remember for the calander check to become stuck in an infinate loop (if one of the lines is not pulsing (to get data back from the chip) but it should not cause the watchdog to fire as that sould be handled unless the bios you have in the system is one I have not seen before (there are many different bios versions across mvs and region.

Raz

Not sure why it won't come up to the error message and why it keeps firing the watchdog with no cartridge in it.

I have a working board here... it works fine without the cart slot board plugged in... comes up to the crosshatch. With a cart plugged in, it works.

The other board won't. It resets if it's by itself or if the cart slot board is plugged in. If I put in my Shock Troopers, 2nd Squad cart then it comes up to a CALENDAR ERROR.

I've narrowed it down that the BIOS is OK by substitution. I've looked at the cart slot board and don't see anything in it that looks like it would be connecting some of the address/data lines on that board. I'm wondering if there's some internconnections in the carts that are happening that are broken on the board. Time to take the cart apart & do some checks.

RJ