JAMMArcade.net – Page 148

Nova 2001 repair log #2

Jun 232015

Another Nova 2001 repair log here after the one from Corrado.Here is the “patient” on the operating table today:

PCB was sent me flagged as “SOUND ERROR”, indeed when I fired it up, the music and sound FXs were only noises.Here is a record for a better understanding of what I mean:

All sound/FXs are generated by two AY-3-8910 chips so I went to probe them and found no activity on all their pins.This was due a missing clock on PIN22 of both (signal is shared) as shown on analog scope:

I could trace the CLOCK signal back to PIN9 of a 7474 @3E and comparing the chip with a good reference one using with my HP10529A confirmed trouble on this output:

It failed miserably when tested out-of-circuit:

Mission accomplished, another arcade PCB preserved!

The Battle-Road repair log

Jun 232015

Got from a friend this The Battle-Road PCB :

Honestly I never heard of this game before.Anyway, it runs on IREM M62 hardware which is the same one of Kung-Fu Master and other games.

My friend said that sprites was completely missing and he was right but comparing what I got with MAME emulation also text/characters colors was incorrect :

So time to investigate and start to study the sprites circuitry which is located on bottom board.Data from the six sprite ROMs are multiplexed by a custom maked “NANAO KNA6034201”, its outputs go to some TTLs (74LS157 and 74LS374) until they hit the RAMs I/O pins (four 2149 DRAMs) which were all stuck HIGH.Probing the custom revealed it did its job, all outputs were correctly toggling as well as piggybacking the four DRAMs didn’t change anything so fault was in the middle.When I probed the 74LS157 @H3 with my HP10529A logic comparator I got this:

So troubles on all its outputs that were confirmed from my logic proble which reported them as stuck HIGH.Obviously IC failed when tested out-of-circuit:

Fitted a new 74LS157 restored sprites but as I said early text/character colors were wrong compared to MAME emulation correct ones.Text colors BPROM was dumped fine so I went to dump the two ROMs containing this part of graphics and I found they were swapped into their respective sockets (on the left the wrong positioning, on the right the correct one) :

This fixed board completely.End of job.

Nitro Ball repair log

PCB Repair Logs, Repair Logs Comments Off

Jun 212015

Got this Nitro Ball PCB from my friend Corrado as not working:

When I first fired it up I was greeted by a solid black screen.Hardware uses, like other DATA EAST games, a custom 68000 CPU in QFP package marked “59” whose pinout is unkown since no schematics are available and nobody has yet figured it out.My first intention was to probe the RESET line on main CPU, this is the first thing I usually do when I got a totally dead board (along with CLOCK pin) but since I couldn’t I started with my visual inspection and I found this:

A 4.7uF 50V capacitor @C43 with anode terminal desoldered from its pad.This may seem a minor thing a but not in this case since this capacitor was part of the RESET circuitry along with a voltage monitor transistor (silkscreening suggests a PST518A IC but a generic BC547 transistor was used instead in order to detect a voltage and generate a RESET signal) :

Once replaced this capacitor board properly booted but all screen was red:

A dominant red color means that blue and green ones were missing so I traced them back to three transistors:

As you can see from picture above manifacturer/assembler used three compatible BC547 transistors compared to original silkscreened part adapting their different pinout by rotating them and twisting the base and collector legs.This caused a short circuit between the base and collector of the blue and green (TR2 and TR3 on picture) transistor.After clearing the short colors came back to normality.

No further issues were found on PCB so I could declare this one 100% fixed.

Hi-Lo EPP-01A EPROM Programmer PAL’s added

PAL Updates Comments Off

Jun 192015

Recently I was given a bunch of old programmers and things from a friend that was doing a clear out.
Among them was an old Hi-Lo System EPP-01A programmer which happened to have 3 x PALCE16V8 devices in it. All of them were locked and I don’t have the relevant ISA card to test the actual programmer out so these are untested. They don’t look too complicated though so im sure they will work just fine.

Nitro Ball PAL dumps added

PAL Updates Comments Off

Jun 182015

Today, after repaired it, I dumped the five PAL16L8 on a DATA EAST Nitro Ball PCB (released in Japan as “Gun Ball”).They all match the ones from Dark Seal 2/Wizard Fire PCB except for the one located @K5 (no labels were on all PALs).Dumps have been tested as working in GAL16V8 targeting devices.I also reorganized these shared Data East PALs renaming them generically (like we already done for Konami and Taito PLDs).

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