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Mystic_Merlin
Joined: 15 Oct 2007 Posts: 496 Location: Bangkok
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Posted: Wed May 13, 2009 3:06 pm Post subject: Supercom Pro.2 almost working... |
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Guess what I found out of a pile of junk this time?
A good old supercom pro (sp3200), this used to be my 1st copier back in the days so I was pretty excited to get its sexy blue screen up and running...well...not so fast...
The poor beast was in a pretty bad shape when I got it so I wasn't expecting much...moreover when I opened the case...
First time I switched it on I had nothing...then I put a cart and got a black screen. After a bit of cleaning and scratching I finally got the blue screen!
- It does display 8M of ram but 0M for the inserted cart.
- When I click play game card I get a NO CARD.
- I can send files from Ucon64 but I get a black screen (I tried only LoRom files). The only "successful" file I loaded was Tomy's BIOS2SRAM but it displayed lots of garbage around the "RESET THE MACHINE..."
- I switched the ram board with a 16M but same deal
It looks badly corroded, but apart from some of the tracks around the battery, continuity tests seemed to work fine.
1) Any idea, advice or test I could run?
2) I'm mostly interested in getting some small roms loaded via Ucon so no big deal if the FDC part is not working. But I'm curious: by tracking down the J4 to DB25 connections, can I determine the proper pinouts to make a custom DB25 to floppy drive connector, just need to add an external +5V DC, right?
Also I wonder if the modification with the PAL chip added to the bottom part of the Supercom was made to load HiRom on this machine?
PS: That night I also got a SPF 16 that literally blew with smoke coming out of the cart port but that's another story...
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CrackLtd
Joined: 05 Feb 2007 Posts: 239
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Posted: Wed May 13, 2009 5:19 pm Post subject: |
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The Supercom basically is identical to the Super Magicom. It just had a different cover (a flat top). What really is interesting is the modification wich can be seen in the last picture. I am pretty sure that this is a so called 'HiRom Fix'. Is it possible to know wich logic chip that is? Maybe i can mod then my Magicom too. Also check the pcb very carefully. I remember you had to cut one or two traces on the pcb in order to make the HiRom Fix work. I did those mods myself back in the 90ies, but i lost all information on that...
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Mystic_Merlin
Joined: 15 Oct 2007 Posts: 496 Location: Bangkok
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kyuusaku
Joined: 26 Jul 2003 Posts: 941 Location: .ma.us
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Posted: Fri May 15, 2009 5:39 am Post subject: |
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Pin 26 is /RESET, you're looking at a bad/old pinout and the wrong side.
I think I have them right:
Code: |
A21 1(I) 20 VCC
A20 2(I) (O)19 A20
A22 3(I) (O)18 A22
A23 4(I) (O)17 A21
A17 5(I) (O)16 NC?
A16 6(I) (O)15 /ROMSEL
A15 7(I) (O)14 A15
A14 8(I) (O)13 A14
A13 9(I) (O)12 A13
GND 10 (I)11 /ROMSEL
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It looks like a HiROM switch, but I don't see how it fully switches ROM, only SRAM... Normally there'd be another 4 outputs for A16-A19. I think the BIOS is modified to rearrange LoROM data to match HiROM instead of switching in hardware. This is actually very simple because though the address lines are mixed up in hardware, when the CPU writes data to the HiROM area, the data will end up in the right place regardless.
If that is the case, the PAL does two things:
-it multiplexes A20-A22 outputs between A20-A22 and A15,A20,A21 depending on A22 and/or A23
-it passes LoROM SRAM access and patches HiROM SRAM access to LoROM
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Mystic_Merlin
Joined: 15 Oct 2007 Posts: 496 Location: Bangkok
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Posted: Fri May 15, 2009 9:14 am Post subject: |
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kyuusaku wrote: | Pin 26 is /RESET, you're looking at a bad/old pinout and the wrong side.
I think I have them right:
Code: |
A21 1(I) 20 VCC
A20 2(I) (O)19 A20
A22 3(I) (O)18 A22
A23 4(I) (O)17 A21
A17 5(I) (O)16 NC?
A16 6(I) (O)15 /ROMSEL
A15 7(I) (O)14 A15
A14 8(I) (O)13 A14
A13 9(I) (O)12 A13
GND 10 (I)11 /ROMSEL
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It looks like a HiROM switch, but I don't see how it fully switches ROM, only SRAM... Normally there'd be another 4 outputs for A16-A19. I think the BIOS is modified to rearrange LoROM data to match HiROM instead of switching in hardware. This is actually very simple because though the address lines are mixed up in hardware, when the CPU writes data to the HiROM area, the data will end up in the right place regardless.
If that is the case, the PAL does two things:
-it multiplexes A20-A22 outputs between A20-A22 and A15,A20,A21 depending on A22 and/or A23
-it passes LoROM SRAM access and patches HiROM SRAM access to LoROM |
I was indeed using a bad pinout, I was using the supercom's pinouts where Pin 1 starts at Pin 5 so I did another drawing based on Anomie's pinout. I also inverted 2 wires in the previous drawing so provided that CART=ROMSEL(?) it shall be more like:
Code: |
A21 1(I) 20 VCC
A20 2(I) (O)19 A20
A22 3(I) (O)18 A21
A23 4(I) (O)17 A22
A17 5(I) (O)16 NC?--->pin cut
A16 6(I) (O)15 /CART
A15 7(I) (O)14 A15
A14 8(I) (O)13 A14
A13 9(I) (O)12 A13
GND 10 (I)11 /CART
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I don't know if the bios has been modified, it displays Supercom Pro.2.
Based on my Supercom's symptoms what would you reckon I should try to fix it? Is it related to the SRAM?
Although the leaked battery damages are important, only a few soldering points are affected, should I bridge them with wires?
Description: |
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68.55 KB |
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13667 Time(s) |
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kyuusaku
Joined: 26 Jul 2003 Posts: 941 Location: .ma.us
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Posted: Fri May 15, 2009 4:40 pm Post subject: |
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Is pin 16 broken off?
Quote: | I don't know if the bios has been modified, it displays Supercom Pro.2. |
If you can dump it, I can compare it to an unmodified Pro. 2 BIOS. The difference would be that after the header is loaded, it checks an additional bit (probably the same bit in the Pro Fighter header) and chooses to write the ROM to [00-3F][8000-FFFF] or [C0-FF][0000-FFFF] based on it.
Quote: | Based on my Supercom's symptoms what would you reckon I should try to fix it? Is it related to the SRAM? |
You should check for continuity between all address and data lines on external cartridge and the pins coming into the Supercom after the PAL. I think they should all be connected except for /ROMSEL which should be gated by the Altera chip, so check for continuity on that signal too.
Quote: | Although the leaked battery damages are important, only a few soldering points are affected, should I bridge them with wires? |
Wires or conductive ink.
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Mystic_Merlin
Joined: 15 Oct 2007 Posts: 496 Location: Bangkok
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Posted: Sat May 16, 2009 1:38 pm Post subject: |
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Quote: | Is pin 16 broken off? |
Yup...sounds odd?
Quote: | If you can dump it, I can compare it to an unmodified Pro. 2 BIOS. The difference would be that after the header is loaded, it checks an additional bit (probably the same bit in the Pro Fighter header) and chooses to write the ROM to [00-3F][8000-FFFF] or [C0-FF][0000-FFFF] based on it.
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Unfortunately I tried to dump it with Tomy's BIOS2SRAM and then receive it from ucon but I get an empty file
Quote: | You should check for continuity between all address and data lines on external cartridge and the pins coming into the Supercom after the PAL. I think they should all be connected except for /ROMSEL which should be gated by the Altera chip, so check for continuity on that signal too. |
Actually most data lines are not connected directly to the external cartridge. Pins 19,20,21,22,49(ROMSEL?),50,51,52 are connected to the 74LS245 of the FDC while 53 is connected to the ALTERA...
Otherwise my continuity traces didn't show up any problem. I fixed the major cuts but it didn't change anything.
What pins are actually involved in the copier reading the cart's memory size?
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kyuusaku
Joined: 26 Jul 2003 Posts: 941 Location: .ma.us
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Posted: Sat May 16, 2009 6:20 pm Post subject: |
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Quote: | Unfortunately I tried to dump it with Tomy's BIOS2SRAM and then receive it from ucon but I get an empty file | If the SRAM is bad you can piggyback the Supercom on another copier to dump it.
Quote: | Actually most data lines are not connected directly to the external cartridge. Pins 19,20,21,22,49(ROMSEL?),50,51,52 are connected to the 74LS245 of the FDC while 53 is connected to the ALTERA... |
That is strange, sure it's not 50-53 to the '245 and 54 to the Altera? I guess everything's fine.
Quote: | What pins are actually involved in the copier reading the cart's memory size? |
All of them need to work really, but I don't think /IRQ is used by copiers.
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Mystic_Merlin
Joined: 15 Oct 2007 Posts: 496 Location: Bangkok
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Posted: Sun May 17, 2009 6:54 am Post subject: |
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Quote: | If the SRAM is bad you can piggyback the Supercom on another copier to dump it. |
Wow I never thought of doing that but that's a fun concept...
Ok so here's what I did, I'm not sure it's the right way:
- plugged the supercom on my UFO
- on the ufo menu I select play card which brings the supercom menu
- transfer Tomy's soft to the Supercom as a ROM (I get a black screen)
- save the sram from the UFO to a disk
Unfortunately it's not working...
I got one information that may help though: the UFO shows up the supercom as a 4M card while the supercom shows a total of 8M
Quote: | That is strange, sure it's not 50-53 to the '245 and 54 to the Altera? I guess everything's fine. |
Absolutely right!...54 bounces on the Winbond before reaching the Altera, that's amazing how much u know these machines!
Well well, I'll try a few more testing. If I'm lucky to find another supercom with the same mod, maybe I'll be able to compare...till then I'm open to any suggestion! (bypass the pal and restore the original traces?...that would be a waste...)
Otherwise I'll send you a copy of the EPROM if I get my hands on a burner one of these days
BTW, nothing else but UV Eproms with similar size can be used as replacement of originals?
Thanks again for your help Kyuusaku!
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kyuusaku
Joined: 26 Jul 2003 Posts: 941 Location: .ma.us
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Posted: Sun May 17, 2009 4:28 pm Post subject: |
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Quote: | I got one information that may help though: the UFO shows up the supercom as a 4M card while the supercom shows a total of 8M
| Right, that is what I meant, just dump the Supercom's BIOS as you would any normal game card... It should be the original 128Kbit BIOS mirrored up to 4M.
Quote: | Absolutely right!...54 bounces on the Winbond before reaching the Altera, that's amazing how much u know these machines! | Well I didn't know/look it up specifically heh, it just makes a whole lot more sense for the '245 (bidirectional buffer) to attach to the data bus instead of /ROMSEL.
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Mystic_Merlin
Joined: 15 Oct 2007 Posts: 496 Location: Bangkok
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Posted: Mon May 18, 2009 5:59 am Post subject: |
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Quote: | Right, that is what I meant, just dump the Supercom's BIOS as you would any normal game card... It should be the original 128Kbit BIOS mirrored up to 4M. |
Right, it make more sense...here I attach it.
Regarding the copiers' EPROMS, nothing else but UV EPROMS with similar size can be used as replacement of originals?
Description: |
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Download |
Filename: |
spcom2.zip |
Filesize: |
92.83 KB |
Downloaded: |
666 Time(s) |
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kyuusaku
Joined: 26 Jul 2003 Posts: 941 Location: .ma.us
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Posted: Mon May 18, 2009 10:15 am Post subject: |
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It's a 100% match with mine, so HiROM support must be partially built in or it needs a HiROM "loader" ROM or there's something I'm missing entirely.
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Mystic_Merlin
Joined: 15 Oct 2007 Posts: 496 Location: Bangkok
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Posted: Sat May 23, 2009 8:35 am Post subject: |
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There's some progress! Err...kind of...
Fix something and another problem arrose...
I found out there was 2-3 traces near the cartridge port on the top layer that had tiny cuts. Tracing those were all the more difficult they were going below the ALTERA socket. Also, I had to cut loose the Hirom PAL on the way...
Here's what it looks like:
Anyway, now the cartridge is being identified, PLAY CARD works fine.
Only problem is that sending by Ucon does not work anymore (it worked before)... The copier freezes (can't browse through menu) and Ucon reacts as if it was not connected.
I guess I'm not finished tracing but any lead to diagnose the problem would be appreciated
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rodneyk
Joined: 29 May 2009 Posts: 15
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Posted: Fri May 29, 2009 9:09 pm Post subject: had a similar problem with my Supercom |
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hi Mystic_Merlin,
I bought a supercom off Ebay a while ago and had a similar experience after opening it... I found a lot of damage to the PCB just like you found.
I am not saying your approach is wrong or anything but if I were in your situation I would handle things a bit differently.
I would document the modifications for highrom carefully and then remove them entirely. I would then document and undo any other modifications and severed connections that were done to the PCB that are not factory defaults, then clean the whole thing carefully. After that I would try to get it to work properly. Since the modifications are not factory made you can't know what the effects will be of them being in place, or if they are even working properly at all. After you get the supercom to work in its original state you can still restore the modifications later if you want.
About properly cleaning off the chemicals that spilled: what I did is I desoldered the entire PCB, cleaned it with vinegar and a sponge used for cleaning pans(soft one, not metal). You do have to watch out not to scrub too hard, only just hard enough to only remove the chemical spills from the surface. What you want is clean copper traces and clean PCB in those areas where the chemical stuff spilled. Only then you can be sure it is all gone without a trace and won't corrode any further. Otherwise corroding will slowly continue still and it could cause future malfunctions. I read that in many fora discussing similar problems. After cleaning you should wash the PCB with soap, then rinse very thoroughly with water and a soft brush and dry it off carefully, be sure to take enough time.
You don't have to desolder everything like I did but if I were you I would at least make sure that the chemicals are cleaned off completely and then after carefully documenting the modifications first try to work from the original supercom layout and connections. At least that way you can be sure you are not overlooking anything.
You can use a continuity test to check all connections if they are intact. If you want to know where any specific connections go let me know, I can help you with that.
Of course, everything you do is at your own risk, use your own judgement and care. I can't judge what level your electronics skill is.
The real technology in your supercom that can't be replaced lies in the EP1810LC. The rest can be replaced and repaired.
By the way, if anyone knows the highrom modification and the programming data of the PAL chip I would appreciate it if it could be posted here. I am also going to examine a Super Wild Card and knowing these highrom modifications might help me in understanding it.
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kyuusaku
Joined: 26 Jul 2003 Posts: 941 Location: .ma.us
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Posted: Sat May 30, 2009 5:14 am Post subject: |
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I've been thinking a bit about the HiROM switch and I have the logic down, but there's one really big problem: hardware alone can't quite automagically detect HiROM and LoROM. It can almost be detected thanks to how predictably HiROM games access memory, but when the game is first loaded as LoROM, the hardware can't tell. The reason is that the CPU reset vector is at $00FFFC, which is located at different physical ROM addresses between Lo/HiROM ($7FFC and $FFFC respectively). Unless the user presses reset to manually switch to HiROM (would be annoying since it'd affect loading/resetting games too and probably corrupt save games), or HiROM games are hacked with LoROM vectors, or the user runs a HiROM "loader" ROM which jumps to the correct address (hopefully in the "HiROM area"), the mod is useless. If you want to put a toggle switch (or few for SRAM limiting) on any LoROM copier though, I know exactly what to do...
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