Special Force
Bally, 1986hi
strange problem with my special force 6803
one of the pop bumpers keeps getting power i checked the contacts and they are
not connected , if i measure i get 44V on the 2 wires from the coil constantly
anyone has an idea , i resolved a lot of problems on other machines , but this i never
had before what am i missing ?
please somebody help me before i lose all of my hair
Ground is switched rather than power. So there is always voltage at the coil and when the switch is closed it will then flow to ground and energize the coil.
If I remember correctly that is a controlled solenoid on special forces so check the driver and pre-driver transistors with a DMM (game off).
hi
thanks for the reply , I did now that the ground is switched , and the problem is without the switch
the coil is energized , I had nothing but trouble with this special force , even wires that are broken in the insulation , never before I had that , I am gone check all of the transistors again , maybe I missed one
Have you replaced the little green capacitor on the switch? Not only are these faulty and cheaply made, but they cause more than just a single problem... sometimes they cause the switch to not work, but they can cause it to misfire as well as lock on. Clip off one leg of it and see if your problem goes away. You can remove it entirely but the point of the capacitor is to lengthen the amount of time that the CPU sees the switch getting closed, making the pop bumper more reactive and more poppy, so its good to replace it.
Here's the manual for you:
http://mirror2.ipdb.org/files/2272/Bally_1986_Special_Force_Manual.pdf
The schematics will help you narrow it down to which transistor is the culprit.
Also,what vintageclub said.
Quoted from vintageclub:Have you replaced the little green capacitor on the switch?
hi no that one i left , will try out what you say, just don't now what capacity it is , hopefully
i can find what uf they are , i have the impression that the whole pinball is very cheapply made
problems problems ,... it's a pinball from a very good friend that i am helping out , i have been
hours and hours on this machine , ones one problem is done 2 others appair
New caps will not solve your problem. Even if they short and cause the switch to lock on, the software is designed to ignore stuck switches. Your problem is with the driver or pre-driver transistor for that coil as Terry stated above.
you're right dothedoo it did not solved the problem , strange other thing i have now
when a rocket is fired , all the light of the rocket lane stays on and the machine freezes
the popbumper ( the one that is working ) still reacts n but no more points are registred
and on the display it say's "rocket fired " is this machine possessed ?
Quoted from tonybelgium:i repleced the ca3081 predriver with a new one in ic base still the same
The machine is not possessed, you are likely adding more problems to the situation by replacing stuff rather than troubleshooting the problem. At the moment you need to check the driver transistor with a DMM. If you don't know how just ask.
I'd recommend a sanity check on your switches before proceeding. First remove the balls from the game, then remove CJ6, CJ8, and CJ9 connectors from the MPU to prevent coils from locking on prior to this test. Then enter self-test switch test with the keypad. You should get message "ALL SWITCHES OPEN"
Once that is verified, and you are certain that the output transistor is good, the best thing to do is to isolate the problem to a section of the board by troubleshooting. Get a DMM/oscilloscope/logic probe on the decoder output for the pop bumper to make sure the upper level logic is not telling the coil to stay on. If it isn't, your problem will be in the section between the decoder and coil, but if it is you have a bad decoder or other upstream logic problem.
Do the above test to verify that the board isn't bad and always sensing a pop switch. Then, remove the switch connector (column or row) and start a game. If the bumper locks on, then it's your driver/pre-driver/logic. If it doesn't, reconnect connector. Now if it locks on it's your switch or short in the PF.
hi
I started the test of the switches , I am getting all switches open , and then chopper top closed
when I look in the manual for chopper top , it should be on bumper 2 but there is no switch
or am I looking wrong ? what is the chopper top switch ?
I measured him out he is good , i did some measurements supply
something strange on the board on tp2 0,4v
I bought myself a logic probe , but I am gone need some help using it
I am not sure how to use it and ,.. so if someone would be so kind to get me started
I really want to learn thanks in advance
tp1 4,9v
tp2 195v
tp3 238v
tp4 45v
tp5 17v
tp6 11v
tp7 11v
tp8 7v
tp9 7v
and on the board
tp1 4,9v
tp2 0,4v
tp3 17,2v
tp4 5,1v
tp54,9v
tp6 4,9v
tp7 4,9v
Quoted from tonybelgium:I measured him out he is good , i did some measurements supply
something strange on the board on tp2 0,4v
I bought myself a logic probe , but I am gone need some help using it
I am not sure how to use it and ,.. so if someone would be so kind to get me started
I really want to learn thanks in advance
tp1 4,9v
tp2 195v
tp3 238v
tp4 45v
tp5 17v
tp6 11v
tp7 11v
tp8 7v
tp9 7v
and on the board
tp1 4,9v
tp2 0,4v
tp3 17,2v
tp4 5,1v
tp54,9v
tp6 4,9v
tp7 4,9v
The measurements of the test points look fine. TP2 on the Control Module is a return (ground), that'd be why you're seeing the .4VDC, it's just floating a little from wherever you are taking your reference ground from. I wouldn't worry about it, and it is definitely not the cause of your problem.
ok , so power unit is ok , voltages on the board ok ,
if i use my logic probe on the pre transitors (who look like ic)
what should i get on the pins , i lookt op the ca6083 and i now there are
6 transistors in it ,...but i don't now what the probe should do there are 3 leds
on it green , orange and red
thanks in advance
There are a ton of videos that cover how to use a logic probe. Depending on the model you may also have to set the switches properly. Once you know what to expect you can start going through the circuit.
Basically what you're looking for is a change in state. So if the pin is low when the coil should not be energized then it should go high when the coil should be energized. Check the input to the pre-driver transistor and then go from there.
You can always compare the readings to a known working solenoid.
hi
I took the logic probe to check out multiplexer 74ls154 and when I take first pin left on top I am getting "1" all the rest is 0 when I trace it on the schematics that should be pin 1 of j6 connector
does this mean the multiplexer is damaged and should be replaced ?
Quoted from tonybelgium:I took the logic probe to check out multiplexer 74ls154 and when I take first pin left on top I am getting "1" all the rest is 0 when I trace it on the schematics that should be pin 1 of j6 connector does this mean the multiplexer is damaged and should be replaced ?
I presume you mean U-14 pin 1 is high, and pins 2-16 are low. If so then yes it sounds like the multiplexer. These don't fail very often, but anything is possible.
ok thanks i did mean pin 1 on u14 , i needed some comfirmation that i was
doing things wright on this 6803 board , let's hope this finishes al the problems i had
with this pinball , a lot, i must say somebody who owned tis pinball did a lot of soldering on
the board , a lot of wires that where cut of , wires broken in the insulation ,......
so i cross my fingers that this is the solution , ilet you know
hi
sad to say that u14 was not the solution to the problem , I am getting dispersed
or I am using my logic probe wrong , when a rocket is fired , all the lights of the rocket lane stays on and the machine freezes the game does nothing , after restart , everything is back to "normal"
exept for the bumper,...
I was wondering if u5 and u6 wouldn't be damaged?
I am almost at the end of my patience ,.....
so please if anybody could help me , thank you
somebody has a 6803 board for sale that works ???
hi
i checked the ram and u2 and u3 , i even put new ones in to be shure , nothing changes
very strange the only ones i am not sure of are u5 and u6
the board starts up and i get 9 flashes from the led , so the processor should be ok
i checkt and recheked the switches did the switchtests , everything seems ok
only the bumper stays on and when i fire a rocket, everything freezes , even the music keeps playing
i've searched the internet forums but nowhere i find something simmular
sorry for the late update on this , the board i repaired was ok
so nowing that i traced almost every wire in the machine
the person i bought it from did terrible things to it several wires were cut and then put together again
in a way ,.....
some wires connected to the wrong wire others had bad connections and everything
was camouflaged , the game works perfect now , one of the worst restorations i ever had to do
that's why i tought the machine was possessed , because every time i took the plafield up and repaired
something or did some measurements and did put it back one or more wires diddend connect
thanks to all who helpt me !!
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Gent
Banning, CA
