F-14 Tomcat
Williams, 1987Any ideas? reading rummaging around thru various posts, im looking at the 7402 U50 on the main board. And or the 7408(i think...or is it 7406) at U56?
Is there any other areas im might need to look into to address this is issue?
Thanks
I'm not sure that anything is wrong with that.
Since pops and slings firing after game over isn't really an issue, and those special solenoids can be fired merely by closing the associated switch, I don't see how this is an issue.
--
Chris Hibler - CARGPB #31
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This was bugging me and I'm pretty sick of the GTF threads today so I had to dig into this. It's not the power that gets cut (makes sense) it's the ground connection and that's controlled by the relay on the MPU board. So it could be a stuck relay (R1), a shorted transistor (Q67) or something in the enable logic. If it's not the first two or you're not sure if it is (should be able to test for a short of either with power off) put a volt meter or logic probe on U50 pin 11 and see if the state changes when you start a game. If it does change check pin 13 then 5 and 6 of U56 and so on up the chain.
Flipper_GRND_Enable (resized).pngpevo
Special Solenoids are not lumped in with the flippers.
Different circuit.
bobukcat provided good advice.
I'll add this...
With power off, test for continuity between J19/1 (or 2) and ground.
If you find continuity, then the flipper power enable relay, K1 (looks like R1 in the schematic snippet), is welded together. I've seen that a couple of times.
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact
https://www.youtube.com/c/ChrisHiblerPinball
http://www.PinWiki.com - The Place to go for Pinball Repair Info
Quoted from ChrisHibler:pevo
Special Solenoids are not lumped in with the flippers.
Different circuit.
bobukcat provided good advice.
I'll add this...
With power off, test for continuity between J19/1 (or 2) and ground.
If you find continuity, then the flipper power enable relay, K1 (looks like R1 in the schematic snippet), is welded together. I've seen that a couple of times.
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact
https://www.youtube.com/c/ChrisHiblerPinball
http://www.PinWiki.com - The Place to go for Pinball Repair Info
R1, K1...whatever it takes...
Quoted from bobukcat:R1, K1...whatever it takes...
bobukcat
The older we get, the fewer people who will recognize that reference. 
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact
https://www.youtube.com/c/ChrisHiblerPinball
http://www.PinWiki.com - The Place to go for Pinball Repair Info
Quoted from pevo:Any ideas? reading rummaging around thru various posts, im looking at the 7402 U50 on the main board. And or the 7408(i think...or is it 7406) at U56?
Is there any other areas im might need to look into to address this is issue?
Thanks
Circuit that controls special solenoids and flippers game up /over/tilt fault:
Problem in the Game Up/Game over signal.
Game up/over signal begins at U10 PIA pin 19
check for missing or stuck signal.
No?
Follow signal thru U50 pin 11 U55 Pin 2 to U50 pin 12
Next U50 pin 13 U56 pins 5,6
Game up/over signal enters pins 8,9 at U50 and to Special solenoid ic's tied to U45 pins 6,3,8,11 and U50 pins 6,3
Check for a cracked SR19
The flipper relay is part of the special solenoid circuitry.
CB2 + Blank forms game over
The game over signal turns on the relay.
Game over also NOR with each 7402 in the special solenoid circuit.
When a special solenoid burns out it will absolutely be able to kill things that far back. Diverters in an f14 burn out seems like the same three or four chips fry.
ok...im very IC ignorant (trying to learn thou) Never used a logic probe before...hmmm looks straight forward enuff... ok im in. Going to start checking various points in above circuit, BUT where do i find a +5v. access point to attach probe?? = hmmm not just yet...kicking myself in azz
Soooo....I poked around with a DMM and found where the voltage changed at 11 from U10 game on vs. off. Hmmm.... so i shorted some pins on the 7402. (Great Idea Right?) anyways heres i what got:
In game over: pin 10 to 13 on U50>>> R1 activates and flippers cut off.=HELL YEA
So i jumped pin 5 on U56 to pin 10 on U50 and again R1 activates ..yup HELL YEA
Pin 6 on U56 to pin 10 on U50 does nothing.
More probing on and around the pins on U50 and U56 in the circuit proved fruitless.
Replacing the 7402(u50) did nothing. (it was socketed already so no big deal)
The 7406 (u56) is not so i have not replaced it yet.
Soo in my Ignorant and reckless wisdom i concluded that R1 is not welded. Q67 must be good and the problem may reside in the 7406(u56)?????yes/no?
Also i need advice on tapping a +5v source on the MPU for a logic probe... because id Really like to learn more how to use the logic probe with MPU installed instead of just jumping pins to bypass IC gates to see what happens...following the circuit to the component in question
Thanks and bear with me cause im justa newbe to the IC circuit game. Im sure the Techs here are going like WTF?...damn fool, but i truly appreciate all the help!
Quoted from barakandl:The flipper relay is part of the special solenoid circuitry.
CB2 + Blank forms game over
The game over signal turns on the relay.
Game over also NOR with each 7402 in the special solenoid circuit.
[quoted image]
Quoted from pevo:ok...im very IC ignorant (trying to learn thou) Never used a logic probe before...hmmm looks straight forward enuff... ok im in. Going to start checking various points in above circuit, BUT where do i find a +5v. access point to attach probe?? = hmmm not just yet...kicking myself in azz
Soooo....I poked around with a DMM and found where the voltage changed at 11 from U10 game on vs. off. Hmmm.... so i shorted some pins on the 7402. (Great Idea Right?) anyways heres i what got:
In game over: pin 10 to 13 on U50>>> R1 activates and flippers cut off.=HELL YEA
So i jumped pin 5 on U56 to pin 10 on U50 and again R1 activates ..yup HELL YEA
Pin 6 on U56 to pin 10 on U50 does nothing.
More probing on and around the pins on U50 and U56 in the circuit proved fruitless.
Replacing the 7402(u50) did nothing. (it was socketed already so no big deal)
The 7406 (u56) is not so i have not replaced it yet.
Soo in my Ignorant and reckless wisdom i concluded that R1 is not welded. Q67 must be good and the problem may reside in the 7406(u56)?????yes/no?
Also i need advice on tapping a +5v source on the MPU for a logic probe... because id Really like to learn more how to use the logic probe with MPU installed instead of just jumping pins to bypass IC gates to see what happens...following the circuit to the component in question
Thanks and bear with me cause im justa newbe to the IC circuit game. Im sure the Techs here are going like WTF?...damn fool, but i truly appreciate all the help!
You are correct that both Q67 and the relay are good but you're tests, or at least the results you posted haven't really ruled anything else out yet. With simple on/off logic in this circuit a DMM set to DCV is essentially the same as a logic probe, you just ground the black lead and test with the Red at various points. If you want to use the Logic Probe look for the 5 or 12 VDC test points (most logic probes can be powered by either but make sure yours does before connecting to the 12V). Now use the meter or probe to follow the chain back, as several of us have described, until the state of that signal stops changing when it should. Then check to see if the state of the input to that chip is changing or not, continue back until you find where it is changing and that's where your problem(s) lie. You can start at the beginning of the chain U56 pin 1 and work forward if you prefer. Since you already replaced the 7402 though I would be surprised if the 7406 isn't bad.
Quoted from bobukcat:You are correct that both Q67 and the relay are good but you're tests, or at least the results you posted haven't really ruled anything else out yet. With simple on/off logic in this circuit a DMM set to DCV is essentially the same as a logic probe, you just ground the black lead and test with the Red at various points. If you want to use the Logic Probe look for the 5 or 12 VDC test points (most logic probes can be powered by either but make sure yours does before connecting to the 12V). Now use the meter or probe to follow the chain back, as several of us have described, until the state of that signal stops changing when it should. Then check to see if the state of the input to that chip is changing or not, continue back until you find where it is changing and that's where your problem(s) lie. You can start at the beginning of the chain U56 pin 1 and work forward if you prefer. Since you already replaced the 7402 though I would be surprised if the 7406 isn't bad.
ive got a 7406 and socket on the way...ill test some more. But im thinking 7406 too.
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Temple, TX