well recheck your work on the transistor replacement. verify it is good. Did you properly adjust the spoon? Use the ball and go all around the skirt and make sure the tip of the skirt is not hanging up on the spoon. As long and the red white wires is the positive the wires are correct. You may want to redo the solder job on the red white.

I think you wasted your time replacing that transistor, you must not have something adjusted right or out of place.

Put a piece of paper between the pop switch contacts and see if it still is constantly energized.

Look here for gaps:

https://pinside.com/pinball/forum/topic/vids-guide-to-rebuilding-pop-bumpers

Look for a white label with red printing, maybe 12" up on the lower right side of the playfield underside.

Should be under playfield, bottom right corner when the playfield is in the full raised and upright position

Sounds like you have a board issue. You did not have the problem until you replaced transistor? Then the locking on issue. You need to recheck your connectors, recheck you work. Maybe a support resistor is shorted. Maybe you dropped a solder ball on board by mistake. HMM?

I would start by desoldering positive for the coil(s) that energize when the machine powers on. You can then power the machine on and then manually troubleshoot things. If every time you power on the machine you have to power it down immediately, you are bound to blow a fuse or burn a transistor up again, or worse.

I am not intimately familiar with F-14. I would be curious if both transistors for these two coils are running through the same IC. Many driver boards have an IC chip (7402) that triggers up to 4 transistors. I have seen these go bad as well. It's not as common, but possible.

Your original problem prior to all of the transistor work you did leads me to believe that the stroke switch that when the pop bumper energizes, breaks the power connection was potentially not working properly. Now that you have multiple coil issues, it seems like different issues.

So... When you replaced the TIP122 or 102 did you check the upstream 2N4401 transistor? They sort of work in pairs. A bad 2n4401 can stress the TIP 122/102. It is generally recommended to replace both when one fails. Further upstream is U45 (7402 chip). May be coincidental but both the left kicker (Q75) and your pop bumper (Q69) are driven by the same U45 chip. Now with all that said, I would be looking for something simpler....since it worked before, albeit weak...then you rebuilt it and now it doesn't work.... Using your DMM with the machine off, see if there is continuity to ground on the coil lug with the single wire. Note that it everything was working, with the game on, you could momentarily short this lug to ground and the coil would fire. If the wire is already grounded, then the coil will fire and stay locked on. If you have continuity to ground, go into the back box and remove plug J19 from the CPU and then check again for continuity from the single wire lug to ground. If you still have continuity to ground then you have a short somewhere other than the CPU and likely right there at the pop bumper.

If there is no continuity to ground on the single wire lug with the machine off and plug J19 removed, then the problem is likely on the CPU. In this case I would replace the TIP 102/122, the corresponding 2N4401 and the 7402 chip at U45. Even further upstream from the U45 is the PIA at U54...that's about as far as this stream goes. Any of these could cause the problem if it is on the CPU. If you do determine that the problem is on the CPU and replace the 2 transistors and the 7402 at U45, you could also then swap U54 with another 6821 on the board (maybe U9)

I am certainly no expert at this stuff and have spent the last 6-7 years just figuring out these bugs. If I'm off base, would appreciate others to chime in.

Nope perfect. To much typing I like to do in short bursts and make them work for it. Follow Freeplay's advice. You should be golden.

Good post Freeplay. Good advice.

rd.

I had the same problem with my f-14 but on the upper diverter, it took out the transister pre driver and the ic. Make shure any wires you resoldered are in the right places, also if you replace the ic you should install a socket so if you have to replace it again you can just pop one in there, been there before.

Yes, normally.

Carefully run a wire from ground to the NON-banded side of the coil diode.

For ground I usually alligator clip to the 1/4" ground braid that runs through the cabinet...even the side rails are a suitable ground. With the game on, just swipe the lug opposite the diode band... the coil should fire. If you wanted to test your coil in question just to see if it fires, you could unsolder the single wire then swipe that lug with ground with the machine on.

When you are checking for something simple, take a good look at the pop bumper switch to be sure there is nothing shorted there. I suspect the problem is on your CPU, but I have had many instances where work I have done has created a new problem so always look to where I was working first. If you do find a short, I would still go ahead with replacing all the components you just purchased.

What do you mean exactly that you have continuity between the right and left pads? Q69 outside legs? You also better check those resistors to see if they are still within tolerance.... From this photo R95 looks a little toasted.

According to the schematics it should be 1/2 watt 68 ohms... Check some others in the same row and see what they read. Your continuity issue could be affecting the read on that resistor... but plan on replacing it anyway. Check that continuity between those transistor legs again with plug J19 removed. I'm assuming there should not be continuity between those legs, but to be sure check a couple others in the row. If there should not be continuity then you'll just have to find the short...something melted together where it burned??? Rally grasping at straws here. Tough when it's not right in front of me. If you can resolve the continuity issue there are ways to still crude make that work. With the transistor sticking through the board you can jump wires from the legs to where they go on the circuit board... Not pretty but have seen it done.

I sent you a PM. Just noticed where you live.

I am not sure why you are replacing U54...that one control the transistors for the upper and lower diverters. U38 is the PIA involved with the Jet bumper Q69. See the special solenoid logic flow chart. Also handy is the diagram that shows you what pulses to expect in the SS circuits.

Special Solenoid Logic Flow.
For Special Solenoids (SSa to SSf), here is the logic flow. This is useful to know if
you are having a problem with a special solenoid.
SSx: 6821 PIA 7407 7402 2N4401 TIP122
SSd: U38 (pin 19) to U49 to U45 to Q68 to Q69

Since pre-Big Guns games use hardware logic to fire the solenoids, there are some
other smaller (and easily damaged!) components that can fail too. Check capacitors
C70 to C75 (.01 mfd), and resistor network SR20 (4.7k). If these become damaged,
a special solenoid can "stick on". Even if your game is Big Guns or later (CPU
controlled special solenoids), damage these components can cause problems.
SSlogic.jpg

OK, this whole thread we are are all helping you to troubleshoot the circuit that completes the ground path to fire the jet bumper, and now from this statement you are telling us that you have lost power at the coil. If you have no power at the coil we have to look at why that is...the grounding/firing circuit can work perfectly and if you are losing/lost power at the coil it will never work reliably.

Start by measuring for +29 to +35 VDC at the bridge rectifier in the backbox (orange wire), this goes to the power supply board (to provide fusing and a few minimal components for conditioning) It enters the PS board at 3J1-2, through the F2 fuse and back out on 3J3 pins 6,7,8. and also through the under playfield fuse that protects solenoids 17-20 (pg 32 owners manual), which are your slings and jet bumper protection (a quick indication that this fuse is dead or the wiring between them is a problem is that left sling, right sling and jet bumper will all be dead)