Hi all,
After few years of trying to solve an Open the Door problem , i managed after Changing Pia at 9B to get game on play. Display is fine ,but i miss all sounds(Even the boot sound . The weird thing is that when i remove ribbon cable that goes to sound board i get the I'll be back sound .

The first time i started the game i got boot sound on a loop.I understand that this was not ok an i closed power. I did a check and i saw that sound ribbon cable was reversed (Pin one from MPU to pin 20 to Sound Board ) . I reseted and then i got no sound . Game and display plays fine.

I have checked voltages at Sound Board. -Fine
Have test all PIA in MPU with Leon's Test Eprom and all Pins 3 to 17 give pulses as should .
Reset is high as should be -right?
Also i have checked both ribbon cables and have continuity.

When checked with Test Eprom....
Pia at 9B that was fixed is somehow related with sound board as pins 18 & 40 go to CN 21 Sound driver ribbon Cable.These two Pin have both +5 Volts (Measure with Osciloscope-no activity )
Also at 7B Pia all outputs are pulsing except for 40,18 (measured at 5 Volts) 39 & 19 (Grounded )

As i have sound only when i remove the ribbon cable i assume that the sound board must be working fine. I have changed recently all 3 Sound Eproms and just for checking i installed the older one with no success.
Any idea of what to start searching will be a headache relief. This game has been inrestoration process for years with no success.

For future reference to anybody that has been searching for a solution(Something that i did for almost 3 years ) to a similar problem :
The game finally plays with sound after changing 7B PIA. Pin 39 should have been pulsing when using a Leon's Test Epprom but there was no action and also Network resistance 4K7 Pin 7 was out of specs again showing problem with pin 39 of the Sound PIA.