Got this untested Konami Salamander from the UK

It was a little bit dirty, but still in good nick. No previous repair work and no broken traces.

First startup showed that the game was stuck in watchdog, so program code was not loaded correctly by the main 68000 CPU. But sometimes it would take longer to reset the watchdog and sometimes it also shouted out one of the speech samples.

So I first took out the program ROMs, shown below, and re-inserted them:

Now the game booted into ROM/RAM test. The screen is a bit garbled, but I could see when comparing to the test screen in MAME, that ROM6 was reported as BAD

I first verified the EPROMs against MAME and they were ok. So unfortunately there was a fault in one of the MASK ROMs. I had a Salamander board since before, so I just stuck the MASK ROMs from that pcb into this one to see if it booted up and sure enough it worked. The MASK ROM printed with 6108 was indeed not working.

As this is a MASK ROM, 1Mbit 28-pin, and not a standard EPROM, I remembered that system11 made a blog post about converting Salamander to the japanese version of Life Force. I have made that conversion as well, and still had some of the pcbs and flash roms.

So I just made one with the Salamander ROM.

And voila, the game is resurrected from the dead 🙂

No other issues, job done!

Got from South Korea this Battletoads PCB for repair:

Board had a strange fault, it booted up but then always crashed after some time (going to a black screen) on title screen just before entering the attract mode :

But if you were quick enough coining up on title screen, you could start a game and play normally but sound was missing at all:

With these premises I started my troubleshoot.Since there was no sound during game I focused on the audio circuit.Hardware uses an audio DSP marked ‘BSMT2000’ , chip’s acronym stands for “Brian Schmidt’s Mouse Trap” from name of his designer:

This is a special masked-rom version of a Texas Instruments TMS320C15 digital signal processor, here’s pinout:

When I went to probe it I found that many data/address lines were either silent or stuck so chip was most likely bad.I removed it:

The BSMT2000 is not often used on arcade hardware (it can be found on many pinballs instead) but luckily I found a spare chip on a Police Trainer PCB :

With a good chip installed the game no longer crashed on title screen but sound was still missing.Probing again the BSMT2000 DSP revealed that pin 20 (data line D6) was stuck low, checking with multimeter it was almost shorted to GROUND :

I traced back this data line to pin 17 of two 74LS374 (used for data latching), these inputs were shorted to GROUND also after cuting their traces to the BSMT200.I desoldered the two TTLs and they failed the out-of circuit testing in same gate:

Replacing them restored sound.Repair accomplished.