HoTD 2 Cab - Naomi not Booting

[coming2u]

Hi Everyone,
I've been reading some of the repair logs on Naomi 1's but haven't been able to identify my issue. Hoping for some suggestions of what to do.

Issue: House of The Dead 2 Cabinet with Naomi, will not boot. Black screen, no sound, no start button lights.

Other info:

• Game was working without issue recently, just didn't turn on one day
• Isolation Transformer working
• Coin door power is on
• CPU and Naomi Case fans working
• Monitor & Speakers are working (plugged in a separate Naomi and got picture and sound)
• Power from power supply is correct
• Measurements on Naomi for voltage also appear correct
• Tried removing cartridge, spamming test button - does not boot
• Tried removing super cap, no effect (did not replace), did not notice any leakage
• Appears to be a diode+resistor setup that someone put under battery to prevent issues

 

[nem]

If the power checks out (you have measured voltages?), then it's probably the Naomi motherboard. The boards die, it happens. Just get a replacement and swap it inside the enclosure. Remember to use the old eprom.

 

[coming2u]

If the power checks out (you have measured voltages?), then it's probably the Naomi motherboard. The boards die, it happens. Just get a replacement and swap it inside the enclosure. Remember to use the old eprom.

If I go that route, is there a term I can search to make sure I find the right Naomi? (Assuming I need the first revision of Naomi in the metal case?

 

[twistedsymphony]

(Assuming I need the first revision of Naomi in the metal case?

AFAIK the metal cased NAOMI was unique to HOTD2, but some other early games did come with the early revision mobo, however I do believe some testing was done that proved any NAOMI1 can run the HOTD2 bios

if you really want an early rev mobo though check look for that large black heatsync in the lower left corner of the board (per your last picture), never versions of the mobo don't have this and it's presence or absence can be seen through an empty cartridge slot.

 

[coming2u]

AFAIK the metal cased NAOMI was unique to HOTD2, but some other early games did come with the early revision mobo, however I do believe some testing was done that proved any NAOMI1 can run the HOTD2 bios

if you really want an early rev mobo though check look for that large black heatsync in the lower left corner of the board (per your last picture), never versions of the mobo don't have this and it's presence or absence can be seen through an empty cartridge slot.

So I did an eeprom swap with my other Naomi and set it to 31hz:

Thanks nem & twistedsymphony ! Now to track down another Naomi....