Category Archives: Repair Notes

Troubleshooting Counterforce drop targets

Chris refers to the Gottlieb drops as the Cadillac of drop targets. I’m not so sure, but they do play well. Drop targets are an annoying mechanism to work on, especially those with added features like trip coils.

Williams drop targets have a failure mode I call slo-mo drop targets. You smack one with the ball, and instead of clicking down, it sinks slowly into the playfield. This comes from dirt. If they’re really dirty, you can hit one, the ball can move far away, and then it sinks. It’d be cool if it happened on purpose.

I got this Gottlieb Counterforce. And it had slo-mo drops. I’ve never seen this in a Gottlieb game. There’s nowhere for the dirt to hide. So, while shopping out a bunch of stuff wrong with this game, I did the drops.

I replaced all the targets (which didn’t match). I followed PAPinball’s guide, which is very good. I didn’t expect this to fix anything, but I hoped it would. It didn’t.

Toasty coil sleeve in my drop target bank.

I cleaned the coil sleeves for the two reset coils, which didn’t really help. So I removed the bank and did a deeper (but still half-assed) cleaning. When I was done, I still had slo-mo targets. (This sleeve is cooked, but it still works OK. Perhaps I’ll replace the coil, but for now, it’s working fine.)

It became pretty clear the problem was with the reset bar not sinking. If one target was already fully down, any other target would drop quickly. But if no targets were all the way down, you’d get slow action because the drop target had to push the reset bar down. So once the reset bar was down, targets would drop quickly.

On this mechanism, there is some freedom to adjust the coil in the bracket. Coils can be twisted slightly relative to their plunger and the reset arm. The coil needs to be square to the bracket, and both coils need to be at about the same depth. The coils can be adjusted slightly so the reset bar doesn’t over-extend the targets out of the top of the playfield, but they need to be square to the mechanism to work correctly.

Now, as drop target banks go, this one has all the bells and whistles. There are seven drops, but there are seven trip coils on the top, too. These are triggered by the computer when it wants to drop a target. In Counterforce, these are triggered by rollover switches and standup targets scattered all over the playfield. Each drop target has a sense switch, but it also has a lamp voltage switch used for “when lit” indicators for the trip switches, and also for the big falling-bomb gimmick.

On my game, one of the trip switches didn’t trip. This appears to have been a coil that was open. The coil was A-18642, but research indicates there are a couple other usable substitutes, one of which was in Chris’ parts bin. So that’s what got used. (Pinball Resource can identify the substitutes, if necessary, but they also have the correct part number.)

I was able to identify that this coil was open by using a multimeter. In the diode setting, I was able to measure the diode of the bad coil — but not of the good coils. For the good coils, when I try to measure the diode, I measure the coil instead. So that was my indication that the coil was at fault.

So far, so good. Resoldering these coils is kind of a pain because there’s so little clearance in this mechanism.

My Counterforce is still torn apart waiting for other parts, but the drops all now work correctly.

So:

  • Make sure the reset arm drops completely, and freely. If not, look for a twist in the position of the reset coils.
  • The reset coils should be positioned so that the coil stop stops the plunger before the drop target goes up too far and shears off the foot.
  • Find the criteria for remote-trip coils and verify they’re all working.

This all applies mostly for Gottlieb drop targets. In any case, I haven’t generally had problems with them once they were rebuilt in home use.

On Williams games with the horseshoe mechanisms, the problem is the horseshoe mechanism. Those things are terrible.

On Williams games with optos, and I suspect those with leaf switches at the bottom of the column, they get dirty and sluggish. I cleaned my BK2K’s targets once and they’ve been great, even after the game was operated for six months at the PPM.

On old Stern games, there’s only one spring that drops the target, so it can be twisted by the spring. If you can get that adjusted correctly, they work great, and can be swept by a good shot. I love these.

Old Bally games are similar, but I don’t have as much experience with them.

I have seen two different drop mechanisms on new Stern games. On my WPT, there’s a service bulletin to enlarge the catch shelf for targets that has cured most of my woes. On my Simpsons Pinball Party, I had a loose connection — otherwise it’s been quite reliable.

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SPP drop targets are too generous

I have more or less finished a shop job on my Simpsons Pinball Party over six years in the waiting. One problem that I have been frustrated with was the drop target bank got confused sometimes and would award “drops completed” several times. Careful observation over an extended period of procrastination and play revealed that the middle target seemed to be at fault.

I actually went as far as buying some new microswitches, just in case one was flaky. Then I remembered to always look for a bad connection first.

The diodes on these switches are mounted on a terminal strip a few inches from the drops. I thought for sure one would be cracked, but they looked fine.

So I pulled the drop target bank out of the game, and one of the QD connectors fell off of its switch lug. I used pliers to squish the switch a little bit together and slid it back on. So far so good!

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Tommy auto-launch

I read on the Intarwebs that when a Tommy can’t kick the balls with the auto fire kicker, it means the mechanism is worn out. DE had a couple different mechanisms and Tommy. The original parts are NLA but you can retrofit the newfangled mech from modern Stern (or Sega) games. Pinball Life had them cheap so I bought one months ago and procrastinated installing it.  Even though the 1994 mechanism is pretty bad, I didn’t relish adding a bunch of new holes to the playfield, and I had been putting it off.

But I looked carefully at my original mech today and it had only a little wear, but lots of dirt, so I just cleaned it instead. Now it kicks quite well!

This mechanism on my game has two different pivot points with a lot of metal-on-metal contact, so naturally it got some much needed oil as well.

Your mileage may vary, but it’s worth checking. The link above mentions the design is bad, and it isL DE went though a bunch of different autofire kickers before finding one where the shooter rod doesn’t plunge into the mechanism. So the swap will be necessary––eventually. 

Now to figure out why I’m bad at the game.

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How not to splice

Does this look factory to you?

Tonight’s lesson for me in vintage arcade collecting: Just because I’ve owned a game for 16 years doesn’t mean I’ve ever really gone through it.

My Robotron had developed intermittent RAM errors after many reliable years. Sure, one of the 24 (!) RAMs might have gone bad, but it seemed equally likely to me that the power supply was probably getting flaky. I got about 4.7V across a cap on the computer board, and after reseating a couple connectors (not a proper fix, I know) I got 4.9. Good enough, and the RAM error is gone.

Looking around, though, I saw this. This is part of the transformer strapping in the main power connector. Why were the wires cut? Why are the wires just twisted together? Why does only one wire have electrical tape? Why is the electrical tape applied wrong? The only answer I am sure of is why the electrical tape is falling off: because electrical tape is terrible. Maybe there were wire nuts on here at some point, but I doubt it. Some of the crimps were not great, either.
The power supply still needs some attention, though. There are some other suspicious splices and a bypassed connector. Oh, well; for now, it’s playing fine.

A decade ago, I tried to put one of Clay Cowgill’s multigame kits in this cabinet. It never worked correctly and I took it out. I wonder if the +5V was a little low even then. Perhaps I should give it another shot.

Edit: A year later, it turns out this wasn’t what was dragging the +5V low. I suspect the bridge rectifier was out. But this was still bad 🙂

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Stuff I’ve fixed on my Tommy so far

My Tommy was really clean, and played fairly well, but I have noticed a few things.

The first and most glaring is the damn autoplunger. I hadn’t remembered that this one is different from the ones on my Simpsons Pinball Party, Star Trek, and WPT. (The Star Trek one is different from the other two.) I have the later model, according to the manual.

The problem with this is that the shooter rod goes right through the kicker. Since my mechanism is a little worn, it’s not consistent. I have made some adjustments, but I’m not satisfied with it. I have read that the new mechanism can be installed, and I’m going to do that at some point.

I put in a weaker spring (but one grade stronger than what the manual says) to make the skill shot easier.

I put in a long barrel spring to keep the plunger out of the kicker’s way, but this doesn’t work that well.

I put a little rubber bumpon as an extra stop in the mechanism so that the kicker would remain vertical, and the shooter rod would more easily clear it.

On my autoplunger, one of the tabs is broken off the coil. This is probably because the coil was installed with the lugs to the right, and it got scraped several times by raising and lowering the playfield. The cabinet is damaged. I changed the lugs to point downwards, and move them away from the coil stop, but ultimately I’ll replace the coil when I replace the mechanism.

I had some random multiball problems. Specifically, in situations where the game should have kicked a ball into play (in particular the Encore ball saver) it would release a ball to the trough upkicker, but not fire. No big deal, the actuator on the switch next to the trough ball release (upkicker) needed some adjustment.

Pop bumpers needed their switches cleaned. I also re-gapped them and put in new spoons. The DE brackets are easy to work with, but they just don’t kick as well as a Williams mechanism.

Lubricated the spinners. Much better.

Software upgraded to 4.0. I will try the unofficial 5.0 ROMs soon. I got these from Matt’s Basement Arcade because I don’t have my own burner here.

NVRAM installed. I used an anyPin RAM, but I didn’t put in a new socket. Seems OK so far.

Skill shot didn’t work right. Sometimes it worked, usually it didn’t. A broken diode on the rollover switch in the subway meant that sometimes it saw a skill shot, and sometimes it saw a Tommy hole shot. Solder fixes this nicely.

Prop rod had been removed and left in the bottom of the cabinet. I took a guess as to how to mount this and mounted it.

One of the playfield stands was missing, and the hole was damaged. I never thought I’d wish for the newfangled rods on a Stern game, but here we are. I got some of the ones from Mantis Amusement that have more attachment points. I promptly bent one, but they’re still better than the factory.

I have been playing this a fair amount and it’s kicking my ass. The slingshots, in particular, are especially cruel. They fire the bar into the 3-banks, and the 3-banks fire the ball into the outlanes. I guess I need more practice.

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