Gameplay was fine but graphics had black lines and music had a lot of white noise.
I ran the maskrom check and it reported two roms as bad, one of which was infact the rom with the sound data.
It doesn’t mean necessarily that the maskroms are bad, can be also that the custom chips have some pins not soldered correctly or the chips themselves being faulty.
The only way is to desolder the maskroms and check on a programmer if it reports pins not connected which means that the chip internally is broken.
After a check with the romset, I decided to dump rom 16k as 27c400 (4mbit eprom with maskrom pinout) and rom 1d as a 27c800 (8mbit 16bit eprom).
Both were reported as having pins non connected properly.
So I replaced maskrom 16k with a 27c400 and the markrom at 1d with a 27c160 eprom (16mbit 16bit eprom) after having doubled the original file in order to prevent the game to access the empty space in case the additional addrr line is not connected to GND or 5V.
I had since ages this untested Phoenix PCB (manufactured by Logitec Co.,Ltd so not the Taito/Centuri version but same layout of it)
Time to build the needed adapter and I powered the board up with this scenario:
All the screen was filled with a pattern of lines and dots.For first I went to dump all the ROMs on the logic board.Doing a comparison with the MAME dumps I got this result:
001.ic45: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed phoenix.46
002.ic46: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed phoenix.46
003.ic47: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed phoenix.47
004.ic48: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed 01.ic48
005.ic49: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed phoenixc.49
006.ic39: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed h6-ic50.6a
007.ic51: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed h7-ic51.7a
008.ic52: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed phoenixc.52
009.ic50: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed phoenixc.39
010.ic40: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed phoenixc.40
11.ic23: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed ic23.3d
12.ic24: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed ic24.4d
All my ROMs matched this MAME set but the two highlighted in the above list were swapped in their sockets, you can clearly notice it in the following picture :
Putting the two ROMs in right location restored the graphics but colors were wrong, here’s a comparison with a MAME screenshot on the right:
According to MAME source, low and high bits of the palette come from two bipolar ROMs @IC40 and IC41 :
I dumped them and, like the two EPROMs, they were put by someone in wrong socket:
ic40: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed mmi6301.ic41
ic41: used in Phoenix (Irecsa / G.G.I Corp, set 2) renamed mmi6301.ic40
Repositioned the BPROMs, colors came back to normal but, when I was playing the game, I noticed two further issues : shield (button two) of player 1 and 2 was not working, tracing back the involved pins from JAMMA connector I promptly found the cause:
Traces were severed, perhaps from some operator to make the game harder ( and earn more money..).I patched them with a bit of AWG30 wire:
The other issue concerned the audio, some effects (like shots and explosions) were missing replaced by some whistling sounds:
With the help of schematics I could figure out that these sounds were generated by a 4006 shift register @IC45:
Clock were present on pin 3 when sounds were triggered but all its outputs were stuck high or low (and totally missing on pin 10).
Since device was already socketed I tested it out-of-circuit in my BK560A where it failed:
With a good IC all the sounds were restored but, before closing this repair, I noticed that the board was randomly missing the boot staying stuck on this garbage screen :
Doing a visual inspection I noticed a missing resistor @R13 and capacitor @C2 near the 8085 main CPU :
Checking the schematics these were involved in RESET circuitry:
The service manual reported them as a 10uF tantalum capacitor and a 100Ohm resistor.:
While looking for some suspicious signals on the GFX area, I found two PALs at locations U31 and U34 that got nothing on their output pins. U31 had healthy looking pulsing signals on its input pins but U34 had some input pins with no signal. These were in fact coming from U31 so that was totally normal.
These PALs are soldered and weren’t dumped yet so I needed to find a working board, desolder the PALs and dump them which was not easy due to the rarity of that game.
Anyway, I desoldered the two suspicious PALs from by board.
I tried to dump them but got an error at pin #20 which is the +5V pin. Sounded they really were faulty as they got no power in order to work properly.
Finally, a good friend got a working board and kindly lent it to me so I could dump the PALs (they were unprotected).
I put sockets on my board, plugged new reprogrammed GALs in place (PALCE16V8 are compatible with GAL16V8). Everything looks perfect now:
There is a total of 4 PALs on this board. I dumped all of them. They are available on JAMMArcade.net
Here’s a picture of the board with the two replaced PALs highlighted in red:
Got myself a new HP logic comparator which had a fault on it.
The fault was with pin 11 on the LED’s.
The schematics for this are available but its so small its pretty easy to trace out just by looking at it.
Using the scope I found all the outputs of the 74L04 hex inverter at location U4 were stuck at around 1.7v. I replaced with with a 74LS04.
While I was poking around I also found the zener diode CR3 had a dry joint so resoldered that too.
Now its all working.
(Ignore the sound, had kids TV playing on Netflix while doing this)
I got this faulty Pyros (US version of Wardner) PCB from Ebay :
It was not really cheap but it was worth the buy since, on the basis of the seller description, I was confident it could be an easy fix.Board showed an ‘I/O ERROR’ upon boot:
I knew from my experience that this board produces the mentioned error when, indeed, there is some troubles with the inputs during the startup sequence (also a simple buttom pressure would cause it).So for first I went to check with my logic probe all the inputs probing pins on the JAMMA edge connector.All of them were high except the ‘COIN 2’ (pin 16 solder side) which was stuck low.I could trace it back to pin 17 of a 74SL240 @20N :
I could measure only few Ohms of resistance between this pin and ground, this meant internal junction was nearly shorted to GND:
Once desoldered the chip, it obviously failed the test:
With a good chip, the board entered in game with no further issue.
Putting the two ROMs in right location restored the graphics but colors were wrong, here’s a comparison with a MAME screenshot on the right:
