Wms System 7 sound oddity? (Chad?)

[MYX]

Hey Chad (or anyone else who might know), I know you have done a ton of pin stuff. How are you with SYS 7? I have an odd problem with my sound. Don't know if you remember, but I recapped my sound about a month ago. It was in an attempt to fix this issue.

Ok, When you turn on the game (cold game) I immediately get sound. I can coin up and Mr. Black Knight guy starts taunting me. I start to play and sound is normal. After about a minute or so, the background trill drone sound continues on forever but no other sounds play. The background sound will not shut off unless I shut off the power and re start it. Then there is no sound. If the game is left on for like 15 minutes it will eventually come back to life with full sound.

My thinking was that perhaps there was a residual charge in the caps and when the game was turned on for the first time I used up that little bit of charge. Then because the caps were old they would not build up the charge properly and take a long time to get to where they needed to be. Could be idiot's thinking too though. Anyway though the sound is better with the new caps, they did not resolve the issue.

So now I wonder if the issue is in the triggering. I thought triggering was all logic, so why would it have to heat up to work? Anyway any help is appreciated.

Also... Side question, but what is the best way to test a coil to see it a problem is in the coil or the wire? My bell has never worked and I have no idea how that sound fits within the game. It this a place where I measure the voltage at the coil and use the game diagnosticsand see if voltage shows up when it should be dinging? I know that on the leaf switch at the coil if I push it to make contact, the whole thing does start to vibrate a little. 

Thanks!!!

[ChadTower]

Do you have the manual?  You should be able to check all of that through the diagnostics.  Fire that coil manually via the coil test and see if it works.

Do the same with the sound... test the sound, make sure each sound tests okay when played alone.  If that tests out okay you probably have a logic issue someplace.  When something works okay upon startup but then fails after a minute or two that is often a loose connection someplace that when it warms up it separates.  The Sys7 is very vulnerable in the +5v and +12v logic connectors pretty much all around the boards, as well as that onerous interboard connector between the MPU and driver board.

If you don't have the manual I may be able to find an electronic copy to send you.  The first place to start is defintiely the built in diagnostics.

[Ken Layton]

Yup, check connectors, especially the interboard connector between the CPU board and driver board. Have you replaced the eprom sockets on the MPU board as these go bad too.

[ChadTower]

I hate that interboard connector.  Makes me very nervous every time I have to pull those boards to work on them. 

MYX, forgot to mention, I have two Sys7s... Black Knight and Laser Cue.

[MYX]

I have the manual, schematics as well as a print copy of all of Marvin's stuff. Yeah, each of the sounds fire when I run the sound diag. I innitially went down the road of the voltage lines and I resat each connector. Reflowed all solder at all connector locations. Got a mini screwdriver and made sure each wire was solidly in place within each connector.

When something works okay upon startup but then fails after a minute or two that is often a loose connection someplace that when it warms up it separates.  The Sys7 is very vulnerable in the +5v and +12v logic connectors pretty much all around the boards, as well as that onerous interboard connector between the MPU and driver board.

Yeah, I was worried about the heat seperation idea.
I reflowed each pin connection on both boards.  As per Marks Sys7 pin page I did purchase a set of pins and receivers to replace them, but haven't had the balls to pull the boards appart again. 

I have not yet replaced the filter cap yet. I am about to pull the trigger on that and all caps for the power supply.

As far as the bell, it does not fire during the diagnostic. This is why I did not know how to check if it was wire vs. coil.

As far as a pin, I love the BK. I brought this one back from the dead and have put a lot of work into cleaning it and trying to make it fully functional. (I got it for free off of Freecycle). The Backglass was off a Wms Stellar Wars. It is one of the nicest BK playfields I have seen. I am just missing top far left hand corner plastic (Yellow and black U shape) and the one that sits at the bottom right of the far left ramp. Also missing the ball gate where the ball comes up to the playfield. I check ebay 2 or 3 times a week for plastics. I upgraded from Stellar Wars to Black Knight about 3 months ago. I found a fairly crusty BK backglass for $50 on ebay. Labor of love I suppose.

Hey, is Laser Cue the one that fires balls like a machine gun?

[ChadTower]

No, Laser Cue is a billiards themed game in outer space with half naked gay looking guys on it.  Not my choice of art but a damn good playing game.

Just making sure the wires are in place in each connector isn't always sufficient.  The terminal pins are only good for a limited number of cycles (cycle = insert/remove).  Some are as low as like five.  Once that is passed, you no longer usually have a gas tight physical connection, which means less reliable connection.  It also means corrosion sets in faster.  A lot of the IDC style Williams connectors from this era are way past due to be repinned.  My Laser Cue needs a few of them replaced and I haven't gotten to it yet.

Those IDC connectors just plain suck and always did... of course, now we're just chasing possibilities rather than tracing the circuits back.

[MYX]

EDITED:

True. I started metering out an issue I have with one column of lighting (the one that has the right side magna save). It is just one of those things where I do not remember how to use the meter in certain situations. Had an electronics course while at Full Sail (Sound School). AnywayI got really good at using a MM and scope. This was like 10 years ago. I guess the info leaked out of my ear r sumthin. I bought a scope on ebay over the summer and I saw in Marvins info that you can use a logic probe or an oscilloscope to see logic pulses. I need to go back and reread all of that. I guess I should just go back and just replace the pins just because it is a good idea in general. As to Kens question, no I have not replaced the sockets, but I did check and they are not the scanbe type. I guess I can replace them too.    . At least this is not as bad as the Gotleib idea of soldering the boards together at the traces. I am really wanting a Black Hole, but this problem scares me.

The terminal pins are only good for a limited number of cycles (cycle = insert/remove).  Some are as low as like five. 

Was that true of the wired connections as well? I knew about the interboard connection. I guess I will be busy tonight. (Finally got a bug to work on it again. )

[ChadTower]

I was talking about the wire connectors.  I forget how many cycles the interboard connector is rated for but that is probably irrelevant now considering its age.

IDC = Insulation Displacement Connector  That's the nonmolex type where the wire isn't crimped in, it's just shoved into a wedge that strips the insulation with a blade to make a connection.  Same concept as for ethernet or phone connectors.

[MYX]

I was talking about the wire connectors.  I forget how many cycles the interboard connector is rated for but that is probably irrelevant now considering its age.

IDC = Insulation Displacement Connector  That's the nonmolex type where the wire isn't crimped in, it's just shoved into a wedge that strips the insulation with a blade to make a connection.  Same concept as for ethernet or phone connectors.

Ok the ones 20 years ago were rated at 5, but are the replacements now any beter? I just pulled out marvins book I printed a while back. The dang thing is over 200 pages. He should have published it. I bought a whole bunch of connectors like these a while back for misc. fixes. I will look to see if they are right for the sys 7. If I replaced the wire side with crimp on connectors, is this taboo or recomended? I never liked the punch on type. (I used to work with phone systems and was shocked at how often punched wires magically came back off). Even when I got the game these seemed like a solid connection, but if I am going to replace them, I'd rather do it once. BTW, thanks for your help!

Oh yeah, have you seen PinballPCB.com?

[ChadTower]

I have seen the replacement PCBs... they have a decent rep, I have no firsthand experience with them myself as I've always either repaired my own boards or had a friend (who is a pro) do it for me.

Don't replace the IDC connectors with more IDC.  Replace them with Molex crimped connectors and replace the header pins too.  That way they both match in age and type.  If you replace just the connector pins then the degradation on the old header pins will speed the degradation of the surface metals in the connector pins.  Plus, you're only doing half the job if you only replace half the problem.

This stuff is all laid out in detail in the marvin3m guide.  Definitely read it a few times, I've probably read the Sys7 guide 15 times.  Print it out and put it by the toilet.   The guide is more than 200 pages but there are a lot of large pictures taking up that space.  I don't think they could publish that guide because it has a LOT of contributors... it's not all written by one person.

[MYX]

I am kind of a do it your self kind of guy. I could not see paying $200 for a board unless I was in a total dead end.

[ChadTower]

Yep.  A lot of pinball guys aren't repair guys, they just want to buy them like toys and use them like toys.  There are lot of "the money doesn't matter" guys in pinball.

Plus, there are a lot of Williams pins of the Sys3-9 out there, and a lot of boards that just aren't worth salvaging.