The general gripe that most people have with SMD parts is that they aren't comfortable with repairing them. I understand that...and with all GLM products, the parts that are MOST likely to fail (and that HAVE historically failed) are generally kept as thruhole parts so that anyone can repair them on their own.

Cheers,

Tony

They weren't GLM boards then. We have only used thruhole optos on the ball trough boards since day one.

Currently we do have one product that uses SMD receiver optos, the Doctor Who 5 bank target board set. The reason for that was due to the fact that the normal receivers that we use on the ball trough boards don't fit there due to a height restriction. We were using a Williams style receiver there, but found that they were too sensitive to ambient light and were causing issues.

So we converted it over to a recessed style SMD receiver which uses the PCB and the target bank itself as a light shield. Works great, but that has been the only area where we've gone SMD for optos, and that was only because it was absolutely the best part for the job.

And on a related note, I would highly recommend that people avoid buying and using receiver optos that are being sold as "factory" or "Williams" original. They are very likely to give you trouble.

This was debated to great length when I started making these boards. At the time I actually designed and manufactured force (impact) sensors for a living and all of the electronics we used were SMD. These sensors were subjected to millions of impacts with near zero failure (usually it was the actual sensor that failed, not the electronics). Boards with SMD parts actually hold up better than thruhole boards and the reason is very simple. SMD parts are very low mass, with a high bonding area. Thruhole parts are the exact opposite, higher mass, smaller bonding area.

You might think that the hole would give mechanical strength, but it is actually a potential point of failure because you can never be sure how well the PCB house made that hole and how well that part has been soldered in. These days we even have to worry about plating separation on thruhole part leads!

Anyway, under vibration, the plating in that hole is going to be the first thing to separate as you have a high mass (thruhole) part constantly working on it. This may cause a disconnect between the top and bottom traces on the board which will oftentimes cause a board to stop working even if the part is still good. The WPC power board is a good example of what happens when these holes go bad (and that board doesn't even get the amount of vibration that the ball trough boards get!). We have to add a pile of jumpers to bypass the broken holes.

And that is perfectly fine. My goal here is to hopefully prevent people from getting the wrong idea about boards with SMD parts on them. If designed right, they are very likely to be better than an equivalent thruhole only board. But design them wrong...Stern....and people are likely to not want to trust anything SMD.

Cheers,

Tony

I'm sorry, I don't know that I have ever seen one that used SMD optos. I'd be just as interested in knowing what was in your friend's machine. Let me know what you find out.

It all depends on how the particular board was designed and built. For high stress applications, most modern PCB manufacturing techniques won't survive as most assembly houses tend to minimize the amount of solder used to bond parts to the board (this is true for both SMD and thruhole). This is one of the major reasons why GLM products are all built in-house as opposed to farming the assembly out to a third party.

Thanks Don! I got it shipped out.

As Atomicboy said, it is likely that the lamp board has cracks in the solder joints (a common thruhole failure on a board that doesn't see much vibration, I might add). Usually the first thing I do when I get a game is to pull all the lamp boards, wash them, let them thoroughly dry, reflow the solder joints on the connectors, lamp sockets, and also the pads for the twist in lamp sockets. The pads for the twist-ins tend to get pitted pretty badly over time, so reflowing them will go a long way to removing any flaky behavior.

Also make sure that the wires to the lamp board are firmly seated. Since the wiring harness hangs upside down, gravity tends to pull those wires right out. Use a jeweler's screwdriver to punch the wires firmly down into the v-groove of those IDC connectors. Might even try that first before pulling the entire lamp board.

Cheers,

Tony

Are you sure that you are measuring AC voltages, not DC voltages?

Cheers,

Tony

Have you checked the power driver board GI headers? These often times need to be reflowed, if not outright replaced. Also, the connectors there, if the wires look crunchy, you'll need to redo them. I've had to cut up to an inch of wire to get to good copper!

Tony