Bringing Embryon back to life

By Spybryon

6 years ago


  • 42 posts
  • 15 Pinsiders participating
  • Latest reply 5 years ago by Pinwiz1985
  • Topic is favorited by 2 Pinsiders


Search this topic for posts matching certain words or written by a specific Pinsider. Or both!

Linked Games

Topic Gallery

There have been 14 images uploaded to this topic. (View topic image gallery).


#1 6 years ago

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.

#2 6 years ago

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?

#3 6 years ago

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

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

LAMP AS-2518-23
TP1 5.2

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.

#4 6 years ago

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

Should I suspect something is wrong with Mpu?

#5 6 years ago

Wish I knew more than nothing. Have you tried checking the connectors between the rectifier and mpu boards? I know this is a common problem probably amongst all machines. Try reseating the connectors and measuring voltages again afterwards. Just guessing I would say TP5 should be 5v. Maybe check for cracked pins on the rectifier and mpu boards?

#6 6 years ago

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.

#7 6 years ago

You have 5v on the voltage regulator so your issue is probably connectors. Start with the MPU j4.

1 month later
#8 5 years ago

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?

#9 5 years ago

Not sure if you checked the connectors on the Power/Regulator board like Barakandl said above, but I'd check those for sure. Almost every Bally out there had problems with them burning up. Usually you can wiggle them and get it to work for a little bit or even pull them off a bit to get a different connection at the pins.

#10 5 years ago

Def check the connectors! This game needed a complete electronics overhaul. When you get the machine running. Let me know if your top left bumper fires randomly with flipper activity. Does it score or no? One of the last electronic problems for me and I'm up the creek on it. Convinced its either and MPU or SDB issue.

1 week later
#11 5 years ago

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.

#12 5 years ago

How many flashes on the sound board? You should have 5! Does it have power? is the speaker good? You should have the as-2518-61a. Press the reset button on the sound board and see if it cycles through the sounds and speech. if not then you got problems on the sound board itself.

My displays were flickering as well, like wavy flickering, turned out to be a cold solder joint. I also changed all the J1 490pF caps that are for the displays too, no issues since.

#13 5 years ago
Quoted from Pinwiz1985:

How many flashes on the sound board? You should have 5!

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.

#14 5 years ago
Quoted from Pinwiz1985:

My displays were flickering as well, like wavy flickering, turned out to be a cold solder joint. I also changed all the J1 490pF caps that are for the displays too, no issues since

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

#15 5 years ago

Can't wait to see pix of this...


#16 5 years ago

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

#17 5 years ago

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

#18 5 years ago

Looks pretty clean on the cabinet inside, and you seem to have the same wear on the PF artwork as I do, pretty common areas near the outhole and upper drop targets. Also my plastics are warped exactly like yours, im gonna try the oven method to straighten them out after the electronics are cleaned up. Which I'm nearly done with, alot of MPU board issues with mine.

In regards to your sound quality, the board does seem to have the original caps in it. They must be replaced, I had the same exact problem. Big daddy enterpises sells an entire kit! Good catch on the EE jumpers, its specific to the Embryon rom's.

Also your solenoid board looks newer, but the caps look fairly old but its hard to tell from the pic. Any further issues with resetting or flickering displays I would suspect the regulator section of it.

My favorite is the backglass Spybryon, it looks mint! MF'in hard to find one in that condition, much less find one period!

I'm a bit jealous you got up pictures of your machine before me haha! Hope to have some pictures up myself soon once its all done!

#19 5 years ago

Very nice looking machine! I usually don't like any more than 2 flippers...but it seems to work well here...


#20 5 years ago
Quoted from Pinwiz1985:

In regards to your sound quality, the board does seem to have the original caps in it. They must be replaced, I had the same exact problem. Big daddy enterpises sells an entire kit!

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!

#21 5 years ago

I passed up an embryon awhile back because of some funky wiring and pf wear around that top flipper.

Cool pin and WIDE as they come. The look on it is super cool.

#22 5 years ago

There's always been a special place in my heart for Embryon. It was one of the first Bally SS pins I worked on / with.
It's not necessarily my favorite pin from the era, but I've always like the artwork, sound speech and "genetic engineering theme on this game (not to mention the "Malfunction" tilt phrase )

... and yes, flip-save was neat to.

#23 5 years ago

Spybryon, another source of sound issues is the two pin connector, that does directly to the speaker terminals, I find that the IDC! A good cleaning or replacement molex will help there too. The 15 pin Molex that sends power and sound select signals to the board goes shitty too, may be time to replace that as well.

The PF wear is always an issue up there, with the ball rapidly changing directions in a circle its bound to wear fast.

Quoted from Blackbeard:

Cool pin and WIDE as they come. The look on it is super cool.

Wide AND HEAVY!!!!!

2 months later
#24 5 years ago

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?

2 months later
#25 5 years ago

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 ...?

#26 5 years ago

Spybryon, awesome news and congrats!! I picked up a dead one recently, and very soon I'm going to have to go through all those steps on mine, and test all those voltages, connectors, etc.

Let me just say THANK YOU for this thread and posting all this stuff in one spot!!

Embryon is a work of art in every way, and I can't wait to get the time to bring mine back from the dead. I'm going to do a stencil set on it as well. What an amazing machine...

1 week later
#27 5 years ago

mechslave, Dont forget my threads too on Embryon, I shotgunned the entire electronics and mechanics manifiest of this machine earlier this year. Plays like a dream. Eventually if funds permit I'm gonna get the PF sent out to HSA and professionally restored and I'll be touching up the cabinet, backglass is a 9/10 with one very tiny chip.

Oh and Spy, replace the spring with the stock one. I think marco specialties has it. I prefer weaker springs where you really have to pull the launcher to send it flying.

1 week later
#28 5 years ago

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.

#29 5 years ago

Pinwiz I'll locate the stock spring, thanks!

#30 5 years ago
Quoted from Spybryon:

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

Love our Embryon too. It still needs some work too but is quite playable now.
The flash in the center only activates when the shot is perfect, meaning both the messenger balls strike the targets in the back at the same time, this will light 2 Embryon letters...

Does anyone know anything about the two different backglasses? Like the history of why there were two, or how many of each were done? Seems there are blue ones and purple ones... or is one color a faded original?..

#31 5 years ago

Some of the best art in pinball on this machine, look forward to seeing the end result.

#32 5 years ago

You will likely have to repin the connectors to the MPU if you have not, I have done this on several of this era machine and it solves flaky lights and timing issues, also, you will want to replace the caps on the driver board in the HV section, and adjust the voltage with the pot there if you have not done this (170v iirc?). Also, for these, ground mods on the driver board are a must and can prevent funky behavior later, all cheap fixes to make it a reliable machine...

#33 5 years ago
Quoted from DareDevyl:

Does anyone know anything about the two different backglasses? Like the history of why there were two, or how many of each were done? Seems there are blue ones and purple ones... or is one color a faded original?..

Ive been wondering this as well I have a purple one that came on my machine is it faded or were there 2 versions i would certainly rather have a blue one myself. just becouse of some mods ill do to mine down the road.

But yes i think this machine is the best of the superpins playwise myself.

If youre having random sound issues thet change i would check over the S&T sockets real well Ive had a few of these where it had some random sound issues and it was a weak pin or so on the socket or some oxidation on the IC pins.

#34 5 years ago

In my research the backglass colors were due to fading and moisture getting to the ink. If the BG is blue then its concidered to be in good condition. The purple came from the red and blues mixing together on the BG so I would expect that to be have been exposed to the elements. I'd love to see a photo comparision.

I've already done the ground mods and repinned every board connector in the backbox, not to mention changed all the bad components. The sound board connector is a known problem with wrong or random sounds

#35 5 years ago

Im unsure if the purple is due to fading it appears to been printed the color originaly no other bally backglass i have has faded at all
Besides if you look at the flyers they have the purple BG it seems but i could be wrong

#36 5 years ago

FTR, I got the purple BG, and the Embryon my parents owned years ago had the purple one too. Maybe the blue tinted BG was a bad batch of paint that got mixed?

#37 5 years ago

Bit of a threadjack but since we're all owners of Embryon,maybe it could help someone else...
Any of you got the random firing from the top left pop bumpers(no scoring) when you flip ?

#38 5 years ago
Quoted from Andre:

Any of you got the random firing from the top left pop bumpers(no scoring) when you flip ?

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

#39 5 years ago
Quoted from Andre:

Any of you got the random firing from the top left pop bumpers(no scoring) when you flip ?

Could be the capacitor on the switch, shorting out.
You can cut it out of the circuit to check, but the switch will not register with quick closure.

#40 5 years ago
Quoted from Andre:

Bit of a threadjack but since we're all owners of Embryon,maybe it could help someone else...Any of you got the random firing from the top left pop bumpers(no scoring) when you flip ?Solutions?

Wrestled with this for the past year. Its actually caused by the pulse of EMI from the flippers feeding back into the wire network. Another cause that irritates the issue further is something called ground bounce. Its a design flaw of the circuit boards in general and known in the bally -35 MPU boardset. The only thing you can do is minimize it by changing out the caps, switching diodes, and making sure the connectors are solid. You may even have to dig deeper and replace the pull down resistors on the MPU/driver board and maybe the 11 caps tied to the PIA's on the MPU. This is what helped solve my random tilting and reset issues too. It also made the top bumper pop lesss It still does it sometimes which isnt too big of a deal for me as its no where near as often as it once was

I made a long thread about this same issue awhile back. Take a look, it may help you with your problem.

#41 5 years ago

If you have EOS and flipper button switches that spark a lot it causes more phantom pops and slings.

Clean your high current flipper switches good and to cut back on the spark and it reduces the amount that this happens. Failing cap on switch matrix switch can also cause this.

#42 5 years ago

Exactly. I added suppression caps on the EOS switchs too. EOS caps are an absolute must, not just to cut down on EMI, but to prolong the life of your EOS switches. Those arcs and sparks destroy the contacts. Also make sure your coil stop is not mushroomed either, if it is, it causes the flippers to be "bouncy" (another common problem with linear style flippers) which makes that EOS switch intermintently arc and get EMI through the lines.

In the end the main culprit for me wound up being the 11 caps tied to the PIA/switch matrix circuits. They tested fine in circuit but would fail after a few minutes of play after warming up. Even after changing them the top left bumper would still pop, but nowhere near as bad.

I did an experiment, added a stronger pull down resistor to that switch row for the top left bumper. It solved the phantom pops but instead it moved to the next switch row making the lower left pop bumper phantom pop. Makes sense since electricity takes the path of least resistance. Its the architexture of the circuit design, there wasn't enough isolation and shielding between the logic and solenoid circuits. The Bally -35 MPU boardset has the logic voltage and solenoid voltage running through the driver board, so it makes sense that a 43VDC trace on the board is going to radiate/bleed over to the 5VDC lines when the magnetic field collapses/builds from a solenoid relaxing/firing

Promoted items from the Pinside Marketplace
From: $ 29.95
From: $ 155.00
From: $ 140.00
From: $ 16.95
From: $ 155.00
€ 3.95
Flipper Parts
From: $ 119.95
From: $ 129.95
$ 7.65
Cabinet Parts
Third Coast Pinball
$ 30.00
Third Coast Pinball
$ 989.00
Pinball Machine
$ 48.00
Cabinet - Other
ModFather Pinball Mods


Note: This is an old thread. The last post was made to it 1,973 days ago. Resurrecting old threads is not necessarily a bad thing, if you think the topic is still relevant and/or your post is beneficial to it (e.g. following up on something). In other cases, it might be better to create a new topic.

Wanna join the discussion? Sign up for a Pinside account, or log in if you already have an account.

Hey there! Got a moment?

Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside