OP
OP
I might need this "dumb'ed down" a little- when I first read it I thought it was the formula for Transparent Aluminum.
What page is "mana01z" on???
what do you do when you've done all you can
- Thread starter vintagegamer
- Start date
I might need this "dumb'ed down" a little- when I first read it I thought it was the formula for Transparent Aluminum.
What page is "mana01z" on???
andykmv
Active member
I might need this "dumb'ed down" a little- when I first read it I thought it was the formula for Transparent Aluminum.
What page is "mana01z" on???
aha! sorry about that. if you downloaded the schmentics from the site i referred to in my earlier post, then mana01z is the name of the file (they are .GIF image files) containing the schematic i referred to.
my notes after reviewing the schematics assumed you have maybe an oscilliscope and/or a logic probe or a multimeter with logic probe built in.
on the LHS of the schematic i referred to you can see the switches (coinup, coin/plya and test) followed by a square box labelled CR.
the square box CR is shorthand for the "debounce circuit" i referred to.
debouncing is a process of cleaning up the change in voltage produced by pressing a switch - you can illustrate what is happening by comparing the effect of pluggin headphones into an amp - have you hear that burst of crackling or static as you insert the plug ? thats what happens when you press a switch - the "debounce circuit" is a resistor and capacitor circuit that smooths out the random voltage spikes so that the 7432 IC that follows the switch has a nice clean signal to work with.
therefore:
- if the cn ctr was triggering multiple times per switch action you would suspect the [CR] debounce circuit and possibly the 7432 IC was faulty. if not, ie you get a nice single click per coin then the debounce circuit and the 7432 IC are working nicely.
this next one assumes you have a logic probe:
- check the clk input to the 7412 flipflop and that /Q and Q and flipping nicely
you could make you own very cheap probe with a resistor and LED and some wire. solder some wire (say RED) to a 470 ohm resistor. solder the other resistor leg to the positive leg of an LED (the longer leg). solder the LED negative leg (shorter) to another piece of wire (say black). put some solder on the free end of each wire (red/black) to make them a nice solid lead to use as a probe. to test, probe the 5v rail with the red lead and probe ground with the black lead. if you get a nice bright led then you have a working probe! you can test for a HIGH output from the 7432 by attaching the black lead to ground and probe the IC output you want to test with the RED lead. when it is HIGH the led with light up (it may be dull depending on the led used and the ic you are probing), and when LOW the led wont light up. to test for a LOW, connect the red lead to the 5v rail, then probe the IC with the black lead. if the output is LOW the led should light up (may be dull ....) in essence this is what a logic probe does except they are setup to show LOW on its own led and HIGH on its own led, and usually a PULSE led too to show a change of stae (H-L or L-H).
now that you have a rudimentary probe, you can do the following:
- check the clk input to the 7412 flipflop and that /Q and Q are flipping nicely for each coin up.
you should be able to work yor way through the coinup signal processing circuits usig a logic probe to see where the signal fails to get passed on. hope that helps!
if you need help following the signal path or how to probe each IC int e circuit then ask!
OP
OP
Thanks for the help with this- as of today, for whatever reason, the game is letting me coin up (some days it does, some days it doesn't- I guess since today's Xmas it's being nice LOL).
When I start a game, the car appears in the lower right hand corner as it should. When you hit the gas to 'start' driving, the car just spins in a crash-type fashion, and you hear the skid-sliding effect. In looking at the attached pic, I'm guessing one of the circled circuits is causing the problem, as near the one with the '55' on it it reads "car control".
Just to confirm, would the '55' component be an actual IC on the board? The one labeled 50 definitely is, but as you can see on the schematic, the 55 component is drawn differently, so I'm not sure if it represents something else or not.
Attachments
andykmv
Active member
TTL ICs as used in this game typically have one or more logic elements per IC. in a single 14 pin IC. "55" is one logic gate of 4 logic gates in a single 14 pin IC package, a 7432 Quad 2-input OR gate package (http://en.wikipedia.org/wiki/OR_gate)
the CL that follows CAR CONTROL could mean anything, but could mean CLOCK - (see below) in context, that it feeds into a 74393 which is a Dual 4-bit Binary Counter, then CL does equal clock - for every pulse it increments the 393/2 counter logic element on sheet (H)
note the top LH corner shows the schematic sheet numer is A in a circle. there is a reference to H above the output of "55" car control so look at schematic sheet mona04z.gif (sheet H) on sheet (H) lower lhs you will see the matching (A) car control reference and connects to [C3] the 86 then 393/2 . 393/2 is the second logic element in the IC 74393 - if you look slightly to the right and a little down you will find the other element in the same IC, 393/1. the numbers next to each line are the pin numbers for that IC. all you have to do then is work out which IC it is on the board!
note that the count pulses from the car control clock on sheet H are gated (allowed or blocked) by the logic element "86" which is an AND gate with inputs inverted (the little circle behind the AND gate where the wire comes in). the counter could represent a timout or number of "spins" before it returns to normal orientation...just a gues without digesting more of the schematic.
at this point, i suggest learning to read the schematics, and work out how the schematics relate to each other by references used (and terminology used in the schemetics)
download this book: http://www.4shared.com/file/36193571/56d1ca2c/TTL_data_book__Digital_Logic_P.html
and starting from page 72 you can see the TTL 74 series ICs whcih show the logic symbols that will match the logic elements you see on the schematic sheets. then you can match the pin numbers and logic elements into ICs that you can then find on the PCBs. bit of a slog but you will figure it out with some study.
the CL that follows CAR CONTROL could mean anything, but could mean CLOCK - (see below) in context, that it feeds into a 74393 which is a Dual 4-bit Binary Counter, then CL does equal clock - for every pulse it increments the 393/2 counter logic element on sheet (H)
note the top LH corner shows the schematic sheet numer is A in a circle. there is a reference to H above the output of "55" car control so look at schematic sheet mona04z.gif (sheet H) on sheet (H) lower lhs you will see the matching (A) car control reference and connects to [C3] the 86 then 393/2 . 393/2 is the second logic element in the IC 74393 - if you look slightly to the right and a little down you will find the other element in the same IC, 393/1. the numbers next to each line are the pin numbers for that IC. all you have to do then is work out which IC it is on the board!
note that the count pulses from the car control clock on sheet H are gated (allowed or blocked) by the logic element "86" which is an AND gate with inputs inverted (the little circle behind the AND gate where the wire comes in). the counter could represent a timout or number of "spins" before it returns to normal orientation...just a gues without digesting more of the schematic.
at this point, i suggest learning to read the schematics, and work out how the schematics relate to each other by references used (and terminology used in the schemetics)
download this book: http://www.4shared.com/file/36193571/56d1ca2c/TTL_data_book__Digital_Logic_P.html
and starting from page 72 you can see the TTL 74 series ICs whcih show the logic symbols that will match the logic elements you see on the schematic sheets. then you can match the pin numbers and logic elements into ICs that you can then find on the PCBs. bit of a slog but you will figure it out with some study.
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