Time Warp
Williams, 1979Just picked up a Time Warp and having an issue with my upper kick out hole. Switch registers in switch test as well as game play but coil won't fire. When coil is grounded it fires, when transistor is grounded coil fires. Coil does not work in sol test either. Every other coil works as well as all lights except for lane guide light next to kick out. Thoughts or ideas? Oh ya coil tests good. Changed transistor and getting the same result.
do you have a logic probe? Put the game in rolling solenoid test and stick the probe on the 7408 output that ANDs with BLANK and check there. Then check the PIA output.
Use the transistor number to follow back towards the PIA using a driver board drawing. The firepower manual scan on IPDB is the one i usually work from.
Top kicker is solenoid 2 on Q17, right?
This is the path the signal follows from the PIA to Q17. You can try to watch the signal at the input and output pins of each part it goes through to see where it's lost, or just start on the left and work your way up, replacing each part and re-testing as you go.
Here is the readout of pia, game is in playing mode
1. Jumping
2. "
3. "
4. "
5. "
6."
7. "
8."
9."
10."
11."
12."
13."
14."
15. "
16."
17."
18.jjumping
19.0
20.0
21. Jumping
22.flashing 0's
23. 0
24.0
25.0
26 flashing 0
27.10.00
28.0
29."
30."
31."
32."
33."
34."
35."
36."
37."
38."
39."
40. Flashing g 0
You can locate IC1+5 using the diagram I attached. The only pin on IC5 you care about is pin 3, where the red line goes in, but you won't see anything useful except when the hole is supposed to fire. If IC5 is working you'll see 0 until the hole fires, then it should jump up to 5V for a tiny bit (it might not make it all the way because the pulse is so quick though)
Quoted from zacaj:It looks like it says 7408N on it too, that number probably means something else
7750 is the date code made in the 50th week of 1977.
Quoted from V_piscopo:Does this chip work?
http://www.marcospecialties.com/pinball-parts/7408
Marco is not specific enough about the part to know. Ask what logic family they will send you. You need a high powered chip like 7408 or 74F08. You don't want 74LS08, 74HCT08, 74HC08.
https://www.greatplainselectronics.com/products.asp?cat=63
Quoted from V_piscopo:Switched Pia's no difference. Reading at 1c 1 pin 12 is 0 wheather I hold the switch or not.
The 7408s in this circuit usually fail on the outputs, maybe compare to a working circuit to be sure. Use rolling solenoid test so you don't have to trigger on the PF.
You could also lift that suspect chip leg off of the board and then see if the PIA does work. Also can check to see if it is shorted to ground with a DMM. Game off. DMM set to diode test. Red lead on ground, black lead probe that 7408 leg and you should see a typical voltage drop (again compare to working circuits). A 0.200 or less reading is usually a good sign of a blown gate.
I will check tonight. I will order a 7F408 chip from great plains as they are in stock also going to grab some transistors and pre drivers from them. Looks like they are OOS of the Tip122's which is what I used when I changed that trans. What is a good option for trans and pre drivers so I can order them. Also should I order a couple pia chips just to have on hand for other games?
Quoted from V_piscopo:I will check tonight. I will order a 7F408 chip from great plains as they are in stock also going to grab some transistors and pre drivers from them. Looks like they are OOS of the Tip122's which is what I used when I changed that trans. What is a good option for trans and pre drivers so I can order them. Also should I order a couple pia chips just to have on hand for other games?
tip102 can be substituted for tip122 and is in stock there.
Quoted from V_piscopo:and pre drivers so I can order them. Also should I order a couple pia chips just to have on hand for other games?
2n4401 and not a bad idea to have a few known good PIAs on hand. The brand of PIA in your picture has been more problematic than others for whatever reasons.
Quoted from V_piscopo:With machine off, In diode test mode with red ground and black on IC 1 pin 12 (solenoid 2) I read 0.558. on IC 1 pin 4 (sol 3) I read 0.362
that is close enough to not declare it bad. 0.000 or even 0.100 is what i look for on the DMM quick and dirty diode test. If it reads differently than every other circuit that is a clue tho something is on that trace it shouldnt be or it is not hooked up like the rest of the circuits are.
I see IC sockets. Are you 100% sure there is continuity from the PIA to the 7408? Buzz it out. You could also do in solenoid test probe right on the PIA leg and then probe on the 7408 leg to see if the signal is getting lost moving across the board from a cut trace or bad IC socket.
I am not sure if GPE sells PIAs right now. Looks like OOS to me.
I will check tonight. I put the machine in rolling sol test mode and tested leg 3 of pia and got nothing, so I pulled the board again and reflowed solder to that socket. Still nothing. I was only into the machine for $100 so after about my third beer decided to splerge and buy a rottendog mpu/driver combo. I will continue to check/work on board and keep for backup or another project w/ shot mpu or driver. I definitely want to thank you guys for the help and I learned a lot about both chips, and reading circut schematics.
Quoted from V_piscopo:New rottendog board came in. Game plays great. Actually a pretty fun game. Thanks for all your help again.
awesome!!! glad you got it going. Now when do I stop by and whos buying the beer?
thanks
Blake
Quoted from V_piscopo:Your always welcome.
ill pick up pong at the same time 
Thanks
Blake
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Burlington, VT