Author Topic: CEI Video Draw Poker 904 Board Question Mark Of Death (Read 4302 times)

RetroRev · « **on:** August 10, 2020, 01:21:40 AM »

Hey all. Long time lurker, first time posting.

Ok so here's my issue. I've got a CEI Draw Poker machine, board 904. I picked it up a while ago and I'm just now getting to it. When I start the machine up -without- the hopper plugged in, it will briefly display the start game screen, like a second and a half, then flips over to a blue screen with a white question mark on it. Here's what I've done so far to attempt to remedy the issue:

Repaired a damaged pad on the left side connector
Pulled all the chips, polished the legs and reseated
Replaced caps at c3, c38 & c39
Repaired a leg on one of the transistors (dont remember which off the top of my head)

Now, a couple questions:

Are there supposed to be two separate power supplies?
My hopper is in pretty rough shape and doesnt spin freely. Should I spend the time repairing it?

I will post some links to pictures and a video shortly.

Thanks very much!

RetroRev · « **Reply #1 on:** August 10, 2020, 04:18:42 PM »

Ok so I guess the last post with images didn't work too well, so here's a link to the video again

<a href="http://youtu.be/Y_QOO51-ufY" target="_blank" class="aeva_link bbc_link new_win">http://youtu.be/Y_QOO51-ufY</a>

And hopefully the images will turn out alright.

RetroRev · « **Reply #2 on:** August 10, 2020, 04:23:42 PM »

Second pic

shortrackskater · « **Reply #3 on:** August 11, 2020, 08:08:23 AM »

From Alan (NLG member badbaud):

The ? may mean the RAM module battery is dead, see attached schematic.
Read the DC voltage from P2-3 to P1-15

Additional schematic added.

RetroRev · « **Reply #4 on:** August 11, 2020, 10:16:51 AM »

That was one thing I kept meaning to see how to check. I'm on my way in to the shop now. Will post my findings.

I've noticed that my ram module looks different than most every other one I've seen thus far. Do the others just have the top removed?

RetroRev · « **Reply #5 on:** August 11, 2020, 01:05:22 PM »

No voltage across any of the legs.

Badbaud · « **Reply #6 on:** August 11, 2020, 01:10:01 PM »

Quote from: RetroRev on August 11, 2020, 10:16:51 AM

That was one thing I kept meaning to see how to check. I'm on my way in to the shop now. Will post my findings.

I've noticed that my ram module looks different than most every other one I've seen thus far. Do the others just have the top removed?

The other ones were never enclosed, those were the lucky ones because the battery could be replaced.
badbaud

Badbaud · « **Reply #7 on:** August 11, 2020, 01:11:22 PM »

Probably why you are getting a question mark.

RetroRev · « **Reply #8 on:** August 11, 2020, 01:34:02 PM »

And I'm assuming the whole casing of the one I have is filled with some kind of epoxy resin making it impossible to replace?

Badbaud · « **Reply #9 on:** August 11, 2020, 05:31:52 PM »

Ya, I tried using a Dremel on one and it was 80% solid.
I did design a replacement PC board layout for a replacement RAM board but looking at how few CEI 904 games are left out in the free world it wasn't worth the effort cost wise.
If I charged $140 per board to recoup my expenses no one would pay for one.

RetroRev · « **Reply #10 on:** August 11, 2020, 05:34:57 PM »

I take it, it requires a custom programmed IC that cant just be bought off a Shelf?

S what if I whittled down to the old battery cut the Leads to Then soldered a new battery to the old leads? I know it sounds a bit Mickey Mouse, But what are the odds that I'd find Another ram board?

Badbaud · « **Reply #11 on:** August 11, 2020, 05:50:21 PM »

No special chip, look at the schematic, it is a standard RAM chip.
Due to the steering diodes in the circuit soldering another battery would not work, the RAM chip would not get the voltage.
Plus attaching a fresh battery to a dead bad is not a very safe option.
The dead battery could explode and the fresh battery could lose it's voltage very fast.

RetroRev · « **Reply #12 on:** August 11, 2020, 05:53:58 PM »

I had meant cut the leads and isolate the old battery then solder a new one in its place

Edit: Had to fix talk to text screwups

RetroRev · « **Reply #13 on:** August 12, 2020, 06:36:29 PM »

Quote from: Badbaud on August 11, 2020, 05:50:21 PM

No special chip, look at the schematic, it is a standard RAM chip.
Due to the steering diodes in the circuit soldering another battery would not work, the RAM chip would not get the voltage.
Plus attaching a fresh battery to a dead bad is not a very safe option.
The dead battery could explode and the fresh battery could lose it's voltage very fast.

Is there a chance I could get a parts list? I can put it together without issue, I just want to be sure im getting the correct components.

Badbaud · « **Reply #14 on:** August 12, 2020, 07:23:37 PM »

Read the schematic I posted for you.

RetroRev · « **Reply #15 on:** August 16, 2020, 03:43:54 AM »

Alright, all parts have been acquired, I believe. Two questions tho.

First: The 1M pullup is on the edge of what the chip needs, would a 330k or 220k work?

Second: Isnt the double diode on the battery feed wasting voltage headroom? Or is it to reduce the data retention current?

Badbaud · « **Reply #16 on:** August 16, 2020, 05:29:37 AM »

The schematic was produced by copying and measuring trace by trace, component by component, an original RAM board that was not potted.

RetroRev · « **Reply #17 on:** August 22, 2020, 12:59:02 PM »

Well first attempt had no results. Figured out I forgot to run a ground trace. Still nothing. Going to scrap the current board and try fresh.

EDIT: Double checked some solder joints and now I get a clicking and the front buttons flash a randomly.

Tried it with the hopper plugged in and it blew a fuse

RetroRev · « **Reply #18 on:** August 22, 2020, 03:20:08 PM »

This is how I laid out my board. Maybe I crossed something up?

RetroRev · « **Reply #19 on:** August 25, 2020, 02:15:36 PM »

Quote from: Badbaud on August 16, 2020, 05:29:37 AM

The schematic was produced by copying and measuring trace by trace, component by component, an original RAM board that was not potted.

Alright. So attempt #2 reproduced nearly the same effects. Some rapid clicking from the various mechanisms of the machine and flashing buttons, then after a moment silence. The screen shows no display.

I've gone over the layout of my board with a fine toothed comb and everything is laid out correctly.

You've built this board yourself before?

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Author Topic: CEI Video Draw Poker 904 Board Question Mark Of Death (Read 4302 times)