flipper button switch or Eos switch make sure your getting good contact with button contact - also there are known flipper board issues - some have bad fuse holders or chips - check to see if the red LEDs light on the board when flipper buttons are being pressed.

I'm going thru same issue with mine at the moment

I had a similar problem with a TFTC.

After several failed attempts to troubleshoot, my problem turned out to be a loose fuse clip on one fuse on the flipper board inside the left side of the cab.

I lightly squeezed the fuse clip ends a bit tighter and have had no further problems with my left flipper failing.

Yes these fuse clips are known to be junk - common issue, you might as well pull the board and check your fuse clips and anything else that may look suspect on the board.

If all else fails - go bullet proof and get a new board - http://rottendog.us/FLP023.htm

I had intermittent problems with my right side and it was a dirty button switch. I had a few fuseclips bad so I replaced all of them in the machine. Easy to do and just one thing less to worry about. - Barry

It's a guaranteed loose fuse clip on the flipper board. FIX IT!

Pull the flipper board, put it down on a flat surface, and press down firmly on each end of each fuse where it is seated in the clip.

The bad clip(s) will very likely "Y" open or split.

RM

Did you physically press each end of every fuse in the game?

Since the red LED is not going off, and assuming it's not an issue with the leaf switches under the flipper button, it may be the switch processing chip(s) going bad.

They are soldered into the board, so it's kind of a delicate repair - de-solder the chips, insert new machine-pin sockets, and replace the chips.

They are cheap to replace, but require some skill.

GPE carries the parts.

4093 IC, CMOS, Quad 2-Input NAND, Schmitt Trigger $0.40
IS-314-MP IC Socket, 14 Pin DIP $0.40

You'll need 3 of each to replace them all.

Or, drop a new Rottendog board in there and be done.

RussMyers

Eos wouldn't cause this problem on data east anyway. Sorry but that was bad advice.

In this case, I would start by getting some fine grit sand paper and lightly sanding between the clips of the flipper switch blades. Then clean where you sand with alcohol. Then test. If that solves it, replace the flipper switch as the sanding will be a temp fix (weeks, months) and removes the gold contact coating.

If not solved by the above: As for the fuse clips, its possible they are the culprit. I would look in the manual and work only in the clip that works for the circuit if the flipper you're having problems with. Not sure which? Remove the fuses one by one until you know. Then is probably sand the clip similar to how you did with the flipper switches. Clean it. And swap fuse with another working flipper to boot. Next if reflow the solder on the back if the fuse clip where it attaches to the board. After all this I would retest.

I would also look at the output wires that run from the flipper board to the coil. They may need to be pressed more firmly into their connector with a screwdriver or such. The pins on the board Kay need reflow.

If these don't help then its probably a more serious board issue. A rottendog board could solve it but make sure you get a newly run board that doesn't have the flipper flutter issues.

yes flipper board fuse clips.

I had a problem with my JP flipper today that had me remembering this thread. In my case, the bottom right flipper would intermittently stop working while the upper right flipper continued to work fine. On the flipper board, the LED was not lighting when the flipper failed, like what you are experiencing.

If the bat was lifted half way while holding in the flipper button, the bat would rise - so it seemed that only the holding voltage was getting applied. In the end, it turned out to just be a dirty EOS switch, as some others had mentioned. Even though the switch was installed new only a few months ago and the leaf contact was firmly closed, it still wasn't making good contact. A quick check with the meter confirmed this. After a few wipes with a business card and I was back in business.

I know you mentioned that you checked your EOS switch, but then you said it worked fine for a little bit. So it may be worth checking again and give a quick cleaning. Just don't want you getting too deep into it if it is something simple.

Back to my original post that I edited - this actually is not bad advice, on JP if your EOS is not set properly your flipper will not work. At least thats my experience.

Ok so what's the working theory here? Eos is stuck closed prevents a high power pulse? If that's possible then I appologize. I'll test this on my tftc.

I'd get new EOS points first. Lots cheaper.

LTG : )

Here is some random information:

Data East used a different EOS theory on their flippers. The new "Solid State" flippers used an electrical timing circuit to pulse a high voltage to the flipper and then fall back to a lower hold voltage. The EOS switch in the Data East flipper circuit allows for a re-application of the high voltage when the flipper is moved far enough by a ball hit. This was not an issue on earlier machines than Jurassic Park, (which do not have EOS Switches) however with the Raptor Pit kick back on the Jurassic Park, the pinball flying back at the flippers would cause it to deflect too much since it only had the lower hold voltage. Data East then aded the EOS switch to allow the full flipper voltage to be re-applied for a short time to keep the flippers from deflecting too far.

Shorting out the EOS switch in a Jurassic Park (or other later Data East machines) will eliminate that pulse of high voltage to "hold" the flipper in the up position when the flipper is hit by a very fast moving pinball. You can verify this yourself by pushing down on the flipper when it is in the up position. If the EOS is working correctly, you wil feel a large push back, if the EOS is shorted out, then you will be able to push the flipper down with little effort.

Shorting out the EOS on the Jurassic Park will not cause any damage to the machine, it just eliminates a function of the flipper electronics.

There is a service bulletin that covers this, service bulletin #53, there is also a bulletin that has a modification to the flipper board (#54) that will keep the pulse voltage high to the flippers even if the EOS switch is broken. This was done so that the game could be played with bad or broken EOS switches.

Service buletins are located here: http://www.sternpinball.com/ServiceBulletins.shtml
Scroll to the bottom to find #53, and 54, and about 6 more that are relative to Jurassic Park.