I finally setup my Embryon which has been in storage for about a year. When I got it the head was separate from the playfield so I finally hooked it up all the connectors tonight to try it. I measured voltages at the rectifier board test points and all measured correct, including the 12vdc was also good.

The problem is with the MPU. LED flickers a bit and stays shut off on MPU. Sound card LED flashes a few times. I measure a varying 2.2 - 3.5 Vdc at TP5 of MPU. I get the same reading on one of the TestPoints on sound card also. I am thinking that's the problem, the low voltage at MPU.

What should I check next to get the voltage correct on the MPU?

Thanks in advance.

I have access to some PC power supplies with +5vdc and +12vdc outputs. Should I pull the MPU board out of the game and hook it up on the bench?

Ok I measured all testpoints with MPU in backbox, all in VDC:

MPU AS-2518-35
VDC
TP1 5
TP2 15.3
TP3 22.3
TP5 1.2
TP6 13.7

LAMP AS-2518-23
TP1 5.2

SOLENOID SDU-100
TP1 5
TP3 4.89
TP5 15
TP6 4.89
TP7 4.89

SOUND AS2518-61A
TP3 14.8
TP4 -4.89

Next I am trying to decoded the sound card led flashes.

Ok sound card flashes 5 times indicating it's working!

Should I suspect something is wrong with Mpu?

Ok I pulled Mpu out and had a closer look. It's clear there is old battery corrosion issues that need to be addressed. The battery was already removed when I bought it but corrosion remains. I need to cut off some corroded components and clean up the board. I hope it's fixable, it looks like it should be.

Great news I have been working on the MPU for a month on my test bench
and finally got it working. I learned how to use oscilliscope in the
process. MPU had alkaline damage so I cleaned it first. This was also causing the bad voltage readings, that testpoint 5 was barely connected to the board.
I had to replace a few sockets, capacitors, and run wires to fix broken traces.
It's still not perfect but it boots. It sometimes gets just a flicker
but I found if I push down hard on the corner of U7, it flexes the
board and boots with 7 flashes. My guess is this is another broken
trace on the board I need to track down.

I tried it installed in the backbox and MPU boots and goes into
attract mode see a few issues:

1) the button in the coin door doesn't go into the test / adjustments

2) game starts after I add credits and push the start button but no
sound is heard. I can push the test button on the sound card and it
will usually play all the sounds fine

3) ball not launched into shooter lane. I have loaded 2 balls in the machine.

4) no coils are active, flippers not flipping, pop bumpers dead

5) score displays messed up looking, flickering and garbagy.
Sometimes when I open and close the lightboard, the displays
temporarily look normal.

6) no switches active on the playfield, no points are being scored

7) cannot add in one more player beyond 1 player by pushing the start
button even though credits remain

Now I swapped my solenoid driver board with a known working one from
Kings of Steel. The only difference I noted was the button in the
coin door to enter the test menu started working. The rest of problems 2-7 were still
there. Since I got into the coil test and could see that all the coils seem to fire fine.
Even the flippers flipped when I hold down the buttons during the
test. However when I started a game, no coils were firing including
the flippers.

Would like to get some advice here where to start on fixing this?

I was looking at Embryon last night and went into the switch test menu. It shows the stuck switch and was showing switch 7. In the manual switch 7 is listed as Tilt (3). Not sure what the (3) is referring to. On the diagram this switch 7 looks like it's near the shooter rod so I opened the playfield and looked at that tilt switch, it was bent way open. It looks like the previous owner wanted to bend this tilt switch open to disable it.

I took a look at the ball roll tilt switch and the ball was rolled all the way towards the back and engaged the switch. After I rolled the ball back to the front of the tilt mechanism, I fired up the game again and it started correctly now! Solenoids and flippers are firing correctly now and score is being incremented with switches.

Now, I still don't have the sound yet. I was looking at the schematics and see on MPU schematic IC U11 is supposed to make sounds activate. I was planning to trace U11 pins to connector J4 for continuity.
Looking for suggestions how to get the sound working?

Also the displays are somewhat better but have flickering, I will try to tackle that as well.

Yes it does get 5 flashes. Speaker is good too because I can push the button and it sometimes goes through all the voice calls.

When I bought the machine it came with an extra sound card. The original one in the backbox wasn't working. When I swapped in the extra one, it worked in test mode when I push the button.

I was just taking a closer look at the sound card in the machine and noticed U12 is present and the EE jumpers are missing. So the extra sound card I swapped in was from a different machine originally. I just added the EE jumpers and pulled IC U12 and sound is now working!

The sound works although there is a *lot* of hum and noise on the signal. So next up is fixing that noise on the sound and fixing the flickering and garbagy displays.

Pinwiz, thanks for the tip. I am going to take a closer look for cold solder joints and double check those caps you mention.

OK here are a few pics. Note that I have not done any playfield cleanup whatsoever. I will be doing that soon and will try to post pictures after the playfield is cleaned.

100_5370_-_Crop.jpg 100_5370_-_Crop2.jpg 100_5369_-_Copy.JPG 100_5371_-_Copy.JPG 100_5372_-_Copy.JPG 100_5373_-_Copy.JPG

few more - note no playfield cleanup has been done yet

100_5374_-_Copy.JPG 100_5375_-_Copy.JPG 100_5376_-_Copy.JPG 100_5377_-_Copy.JPG 100_5378_-_Copy.JPG 100_5379_-_Copy.JPG

Yes, still have original caps in the sound card. For some reason, sound has fixed itself on it's own! Well atleast for the time being, I know it wont last that way.

I have already ordered and received a cap rebuild kit from GPE. Ed is great guy, he even helped me correct my order when I wanted to sneak in one of those memory caps into my order!

Up next is fixing the score displays then a good playfield cleaning!

Thanks for all the kind words and encouragement! Yes it's a superwide body! It's wide but much more fun than other widebodies I have played. Girloveswaffles you are correct there is really something special about the art and speech! I meant to post earlier but didn't get around to it. On labor day weekend a good friend came over and we started pulling plastics on the playfield and testing every switch. We managed to fix one non-working inlane (outlane) switch by removing a bad capacitor. It's not needed anyway.

Next one of the flipper's started chattering and we had to fix that as well. We figured out the low power wasn't working but had no extra coils on hand. We really wanted to play so I unwrapped the coil by one turn on the low power wire and hooked it up. Then it could play.

Hilarity ensued when we stared playing. I had left a few things off of my parts order, specifically one of the large rubber rings in the upper left as well as some tiny post rubbers. When we hit the center ball target a few times, the post rubber was so old and worn out it started chipping away and released the center ball. Instant multi-ball!!!

I just had a look thru the manual. I can't seem to find any mention of these post rubber parts. Can someone help me with the part number or where to get these post rubbers? It's the one that hold in the center captive ball (and all the rest of the captive balls I think).
Or what the measurements of these are?

I have Embryon running well these days. I just swapped one of the flipper coils that was chattering. The chatter only started after the machine and coil had warmed up after playing a while. Still on my todo list is fixing the occasional display flickering. It's got to be some of the IDC connectors being flaky.

One thing that I am not sure about is the plunger spring. I put a brand new one in there and its super stiff. If you were to launch the ball and full plunge it would really fly out the shooter lane. That's just going to make the wear spot worse up top I guess.

Originally someone had stuck 2 weak half sized springs in the plunger, I suppose it was done to keep the ball launch speed slow.

What would you do, leave the new stiff spring in there or go back to weak springs or ...?

Mechslave thanks for the compliment! I certainly hope someone can benefit from the info!

Well I really need to get in the backbox and put some new connectors on there. The flickering displays is gone for the moment, but no "EMBRYON" lights on PF are functioning

Another lingering problem is there is no Flash when you spot a EMBRYON letter.

Pinwiz I'll locate the stock spring, thanks!

Mine doesn't do this I don't think. I'll pay closer attention and see if it ever happens.