Often in arcade games they start the counter chips other than at 00 which doesn't make sense to me why you would want to start the counter and load it at a different value other that start it at 00, any reasons why they do this?Plus when using the counters carry out bit in arcade games to do what with the carry out bit?
at 4:28, what did you knob did you adjust to make the signal on your scope go from fuzzy to still and clear when you was looking at that clock signal. thanks
The timing resolution (X axis) adjustment, basically made each grid block a smaller time frame so you could see the fast movement. If you have an o-scope and are not used to it check out some of the learning to use an oscope videos on you tube (I don't have any) it will REALLY REALLY help you out. just need the basics. and very important practice on some known good signals (like clocks on a working board) before trying to repair a board, otherwise you'll be fightingg your tool rather than having it help you. It really really really really one of the best uses of your time to make you maximize your tool.
@arcade-cabinets thank you for the info! I have done all my repairs with just a logic probe, i bought the siglent sds1104x-e almost 2 years ago, just seemed like alot so i never messed with it up until now, "IN TRAINING" lol
@@jeremylester6537 it is one of the best tools you can have and I suggest you use it! but you do need to spend some time learning the tool or it will just cause confusion. spend 1-2 hours getting the feel of it and it will increase your repair ability 100x no joke.
How can you verify the arcades game resolution and pixel grid using an oscilloscope? because each arcade game resolution is different with different H&V columns and rows numbers some games are 256X240 and other arcade games are different. How do you measure and verify an arcade games resolution to know the arcade game is 256X240 or something other? Can the Oscilloscope or Logic Analyzer able to count the arcade games H&V to know what the arcade games resolution and pixel grid?
I'm not sure if there is a bad RAM chip or get a DCD error or BTS error only in the RAM region that this will change and alter the ROM signature value to a totally different number can this happen? can a bad ROM chip or getting a DCD error or BTS error on a RAM chip cause the ROM signature value to change and alter to a totally different ROM signature value?
I don't understand why the vertical counters to create the vertical sync signals are being loaded as a default as 7C. Any reasons why the vertical counters in Ms Pac man are starting being loaded at 7C? it doesn't make sense to me. Also when the vertical counter chips have reached FF how does the CPU know when to send the Load pulse to the Vertical counter chips?
But most arcade games Z80 and 6052 CPU use a 16 address lines but the ROM chips are only 11 address lines any reasons why? This is what confuses me is that all the ROM chips 2716, 2732, 2516, 2532, etc are all 11 address line inputs so each ROM chip can only hold up to 2048 address. I would think a 2732 or a 2764 would have more address to hold compared to a 2716 ROM chip, but it seems that a 2716, 2732, 2764 all just only have 2048 address maximum? I might be confused how to calculate using a calculator on how many bits a 2716, 2732, 2764 can hold, how can i calculate using what formula? The maximum address is 2048 but the "amount of bytes per address" might be different for a 2716, 2732, 2764?
I'm not sure if all arcade games have separate TEST ROM chips, 1.) What are the differences between using the arcade games test mode diagnostic test program compared to using a separate TEST ROM chip? You remove one of the ROM chips from the socket and instead a TEST ROM chip. The Test ROM chip does more deeper level ROM/RAM test I'm guessing 2.) Some repair technician say that dual wipe sockets are better than the machine pin sockets. I thought that the machine pin sockets had less intermittent issues and dual wipe sockets cause more intermittent issues.
1) test roms are usually found for games that didn't have test roms built in. some people have written "better" test roms for games that do more stuff. 2) I do not recommend machine pin chips. I like dual wipes for a bunch of different reasons.
@@arcade-cabinets They have test rom chips for arcade games that have built in test modes also. I'm guessing people have made these AFTER the 80's game programmer. 1.) I wonder why I can't use the same TEST ROM chip for any arcade game because the TEST ROM is doing different types of ROM test and and RAM tests so i would think the TEST ROM chip should work for all arcade games. What do you think makes the difference in the code that the test rom chip won't work for ALL arcade games? 2.) Can you list why you like dual wipe sockets compared to machine pin sockets?
bill williams different games have different memory layouts. Some chips can be used in Multiple games if the system architecture is the same. In the 80s manufactures often made a platform that could just have different Roms for each game just by swapping Those often can use the same test rom chip. However each game has different code so you cannot have. A single test rom that checked the other Roms only ram and sound and video. I don’t like machines pins because 1) there legs and connectors are big so it’s hard to solder them in correctly, often people will try to solder them in and overheat things in the process destroying the traces and via’s, or bridge traces. Then 2) it’s almost impossible to remove them once installed without destroying the traces 3) it’s hard to insert chips in there everything has to be slight perfectly and often pushing them In will break the legs
@@arcade-cabinets ok thanks for the help 1.) So are you saying that the since each arcade game has a different address mapping/address decoding you can't use a single test rom chip for ALL arcade games? or it's not about the address mapping/address decoding? 2.) If a software programmer wanted to make ONE signal test rom chip for all 80's arcade games what would need to be done in general?
Do you think you can make Z80, 6505, 8088 complier youtube videos showing how to read the arcade ROM chips and turn the hexadecimal code into instructions and going over the coded game instructions. Like take Pacmans ROM chips and read the hexadecimal code and use a Z80 or 6505 complier to convert the hex code into instruction and go over the instructions of the game code to learn from in the youtube video lesson. Do you know how to do this?
arcade cabinets, I have seen circuit pad jumpers on arcade games for I/O buffer chips, what are they used for?Atari Battlezone N2 and K3 , LS244 , Pin# 1 and Pin#15 have circuit board jumpers, any reasons why?
Some games can be configured to use different chips. I don’t know offhand but I think battle zone could use different buffers depending on what the manufacturer wanted to use at production time. Cost and availability is always a concern for manufactures
Oh ok thanks, so those Circuit Pad Jumpers are mostly used for different pin out chips? Because I have see in arcade games schematics a lot of circuit pad jumpers for RAM chips and ROM chips also which I think ground certain address lines. The control lines and data lines stay the same I think.
When you read an arcade games program ROM chip, there is 16 rows with hexadecimal values. How you know which ones are the Opcode values and which ones are the data values in the Z80 language or 6502 Language? because it will display 16 rows of hexadecimal values for each address offset, but how do you know which ones are opcode values and which ones are data values?
wayne Gram you have to know the machine language specifications. The specifications tell you how to decode each instruction which then you have to do one after another. Some cpus machine languages however are designed to be easy for example each instruction might be exactly 32 bits and x or those are the instruction and y are data values
But when you read arcade ROM chips it will display the Rows and columns of hexadecimal values. The address offset values in the rows and there is 16 columns going across the screen with 2 hexadecimal values per column. Are these only just hexadecimal data or are these hexadecimal values Opcodes values?
arcade cabinets, how do you set your oscilloscope to count the logic data? because I have heard arcade repair technicians doing this to troubleshoot serial & parallel shift registers to "count the data" on the inputs and outputs of shift registers, any reasons why you would want to "count the data" in logic signals? why would you want to count the data for what kind of logic signals in arcade games?
wayne Gram I’m not sure what you are asking. An oscope can count the number of times a signal goes high or low or frequency of a signal but I don’t know what your asking
Some Oscopes will have a counter that "counts every data pulse" the counter will show a value of how many counts the logic pulse is for that logic signal. Most Logic Analyzers I think do this. If you're measuring a clock signal the counter will count every data pulse of the clock signal. What I'm confused about is when would an arcade repair technician ever use the counter to count the data pulses for troubleshooting shift registers or V&H Counters chips?
When an I/O data buss buffer IC chip has one short or open pin it causes ROM signature issues. Any reasons why if only one data buss buffer pin that is either shorted to ground, shorted to +5vdc or open floating can cause ROM errors on the fluke 9010A giving different ROM signature that are correct ROM signature?
@@arcade-cabinets When the Data buss Buffer has one input or output pin shorted to ground or shorted to High +5 or floating, when you type in the ROM signature in the Fluke 9010A it will say there is a ROM signature Error and it doesn't match the ROM signature. I'm confused because the Buffer IC chip should not change the ROM signature even if one input or output pin is shorted to ground, shorted to High or floating. But it seems that the Buffer IC data buss chip can change the ROM signature, but I don't understand why or how it changes the ROM signature.
All arcade games use 2V to 128V and 2H to 128H sync signals. 128V Multiplied by 128H = 16, 384 bits or pixels? Does this mean that all arcade games are 64K pixels?
How does the arcade games MPU Vector Reset affect the address decoder circuit? The 6502 MPU vector reset address, MPU Z80 vector reset address, MPU 8088 vector reset address are all different address values. How does the MPU vector reset address does what to the arcade games address decoder circuit?
The address decoders are not affected by the reset vector. The reset vector is defined by the chip manufacturer and the system must be built around this.
@@arcade-cabinets When you first turn on the arcade game, what is sending a signal to the Reset vector? I thought the arcade games reset circuit or address decoder circuit sends out an address to the MPU to the MPU's reset vector. I'm not sure what the MPU reset vector does or how the watchdog circuit is sending out a pulse to the MPU reset vector.
When reading the game codes contents from an arcade games ROM chip, what assembler can I use to convert the game code into reading the code easier? Can I load the game codes contents into an assembler and the assembler can convert the game code into reading the code easier and maybe debugging troubleshooting the code?
you need a disassemble for whatever CPU that is used. MAME in debugging mode has a disassembler. Also check out GHIDRA (ghidra-sre.org) it's amazing though a bit complicated to get started with.
@@arcade-cabinets but most ROM and RAM are using the data buss all the time, so I don't get what devices would be sending a BUSACK bus acknowledge signal
@@waynegram8907 ram and rom are not considered independent devices. they are just responding to requests from the cpu they do not try to use the bus on their own.
@@patreonarcades4476 what would use the bus on their own? what devices and IC chips would send out a BUSACK bus acknowledge signal to take over the data buss?
It doesn't make sense to me how the Fluke 9010A can say the ROM signature is OK when the ROM signature is the wrong signature because there is an addressing issue. Why would the Fluke 9010A say its OK when the ROM Signature is the wrong signature? It happen when you have an addressing issue but I would think the Fluke 9010A would say its a bad signature error but it doesn't, any reasons why?
I dont' remember the specifics of this video, but if the addressing circuits where messed up then the fluke signature check should NOT be successful, that said it's possible that the addressing circuit chips etc work OK for the regions that control the ROMs but the parts that control the RAMs are not ok. that would allow the ROM access to be OK, but not the RAMs. Keep in mind although most addressing circuits are pretty simple they do consist usually of at least 3-5 chips and not all chips are used for all parts of the address range.
If the address circuit chips are OK for the regions that control the ROM why would the ROM signature be incorrect wrong but the Fluke 9010a says OK with no errors? Or what would cause the Fluke 9010a to say the ROM signature is OK but the ROM signature is wrong and incorrect?
The Fluke 9010A will say its OK but the "ROM signature is wrong" when comparing it to the ROM signatures on the internet. The Fluke 9010A will say that the ROM signature is OK with no errors when the ROM signature is wrong or " just a totally different signature compared against to looking up the Correct ROM signature on the internet. This is my main question is why does the fluke 9010a says the ROM signature is OK no errors but really its the wrong signature? I would think if the address decoder circuit is not working correctly it would make the ROM signature bad but it doesn't because the address decoder circuit or an addressing problem on the arcade games doesn't affect or do anything to the ROM signature it seems. The ROM signature is separate from the address decoder circuit and addressing issues because it has nothing to do with addressing. So the Fluke 9010A will say that your ROM signature is good and OK when actually its wrong compared to the internets ROM signature for that arcade game. I'm not sure why the Fluke9010A is saying its good and OK when the ROM signature is incorrect or "is totally a different signature" but the Fluke 9010A will say its OK and good. I'm not sure what causes the ROM chip to output totally different ROM signatures but I don't think the address decoder circuit or is the address buss has shorts or floating lines would this change the ROM signature to a totally different rom signature value?
ARCADE CABINETS, the FETs or Cells inside the 4116 dram needed +/- 5 and +12 because of what reasons to store the data bit? because 4164 are Dram also but the cells fets only needed +5vdc to store the data bit, why?
@@arcade-cabinetsThanks for the help. Not sure if you know the answer to this but For Bally midway Galaga they used a custom sync generator chip i'm guessing for the V&H sync counter chips are built inside this custom sync generator IC chip. How does the Sync Generator chip work, what does it do?
@@billwilliams6338 basically what you said, they just made a chip that combines a bunch of other chips/logic into a small single chip. Namco used this chip on a bunch of games so it was probably cheaper to just make a custom chip that had the counters and some other functionality than to use the space on the board and a bunch of other chips.I don't know all the functionality that this chip does but it certainly handles timing as well as data buffers.
ARCADECABNIETS< I'm confused on the video sections in arcade games from the differences of Raster arcade games compared to Vector arcade games. Raster arcade games use Horizontal and Vertical sync signals for the CRT positioning coordinates and uses a Color PROM chips to choose which colors tints etc. Vector games don't use H&V sync signals but uses Deflection signals. I don't know what the differences are between H&V Deflection signals compared to H&V sync signals. What are the differences between H&V sync signals compared to H&V Deflection signals or are they the same thing? Vector arcade games don't use a Color PROM chips like Raster arcade games? In Raster arcade games the game board outputs an RGB signal with V&H sync signals which is 5 separate wires to the CRT monitor board? In Vector Arcade Games the game board outputs H&V Deflection signals and RGB signals to the CRT monitor board?
bill williams: honestly I have no idea how vector monitors sync or if they even have a concept such as such. I don’t usually mess with vectors. I thought vectors just draw/deflect the beam as needed using a +/- charge on each axis as needed but I could be wrong, I never mess with vector video hardware honestly so I could not really say with any certainty.
@@arcade-cabinets ok thanks i thought maybe you knew about arcade games in the 80's that were vector and not raster because some arcade games in the 80s were vector
@@billwilliams6338 I don't know of any raster games that have anything like that honestly. I think it was just a Atari vector oddity. (DMA is NOT an Atari vector oddity) but the whole vector video circuit halting the CPU , I cannot say I've seen on anything but Atari vectors. (and I"ve only seen vectors that are Atari, maybe other vectors do to but I don't know) -brian
every arcade games in the 80's had separated address decoding circuits for the video hardware, video RAM, video ROM chips. I don't understand why they made the separated address decoding circuits for the video circuits to not be able to be accessed by the CPU to read and write to the video circuits, video RAM, video ROM, any reasons why they did this? and not use the same address decoding circuits for the game code why have a separated address decoding circuit for only the video sections?
How do you calculate using a calculator formula the maximum data bits that a single ROM chip can hold? 2516 ROM or 2532 ROM chip how can you calculate the max data bits that it can hold
2 to the power of the number of address lines. if there are 11 address lines it's 2^11 or (2x2x2x2x2x2x2x2x2x2x2) = 2048 and these are the number of bytes. for exapmle a 2716 or 2516 has 11 address lines (a0 - a10) so it has 2048 addresses each holding 1 byte of data.
When testing a ROM chip and you didn't have the signature value. When you type in the ROM start range and ending range on the Fluke 9010A and "enter in signature 0 value", you will get an error message when you press the MORE button which the fluke 9010A will tell you what the ROM signature value should be 1.) How does the Fluke 9010A know what the ROM signature value should be? 2.) This can be a way of cheating by get the ROM signature value without knowing it? 3.) When you REMOVE the ROM chip from the socket the Fluke 9010A will tell you a ROM signature value any reasons why?
1) the fluke knows how to compute the checksum. its in the flukes code. 2) assuming your game is working correctly, yes that is a way of determining what the signature should be, it only works if your sure your game is working though! 3) Because the CPU always sees "something" if the ROM chip is not there usually it shows up as 0xFF for each address that you read.
@@arcade-cabinets thanks for the help 1.) But how does the fluke compute the checksum even when you have entered in the wrong ROM Signature value? 2.) When removing the ROM chips from the sockets the fluke 9010A will give you a ROM signature value that is a different ROM signature value compared to when the ROM chip is installed in the socket. Why is there two different ROM signature values?
Arcade games use counter chips with a carry in and carry out, I'm not sure why would you want to use the carry in and carry out because it changes a 4 bit output counter to a 5 bit output counter. The carry in and carry out changes the counters output value, but not sure when arcade games use the carry in and carry out for what reasons?
Ms pacman has a custom IC chip that interfaces the game ROM chips and RAM chips with the character RAM chips and sprite RAM chips. The Fluke 9010A can read and write to the character and sprite RAM chips with the Customer IC chips Removed. When the Custom IC chip is Remove why can't the game ROM chips and RAM chips able to talk with read and write with the character ram chips and sprite ram chips?
That's not correct the game ROM chips and RAM chips never talk to sprite RAM or ROM. RAM and ROM cannot initiate transfers of data they can only respond to requests from the CPU or the video hardware.
The fluke 9010A POD circuit is a Decoder circuit or what is the POD circuit doing?
Often in arcade games they start the counter chips other than at 00 which doesn't make sense to me why you would want to start the counter and load it at a different value other that start it at 00, any reasons why they do this?Plus when using the counters carry out bit in arcade games to do what with the carry out bit?
at 4:28, what did you knob did you adjust to make the signal on your scope go from fuzzy to still and clear when you was looking at that clock signal. thanks
The timing resolution (X axis) adjustment, basically made each grid block a smaller time frame so you could see the fast movement. If you have an o-scope and are not used to it check out some of the learning to use an oscope videos on you tube (I don't have any) it will REALLY REALLY help you out. just need the basics. and very important practice on some known good signals (like clocks on a working board) before trying to repair a board, otherwise you'll be fightingg your tool rather than having it help you. It really really really really one of the best uses of your time to make you maximize your tool.
@arcade-cabinets thank you for the info! I have done all my repairs with just a logic probe, i bought the siglent sds1104x-e almost 2 years ago, just seemed like alot so i never messed with it up until now, "IN TRAINING" lol
@@jeremylester6537 it is one of the best tools you can have and I suggest you use it! but you do need to spend some time learning the tool or it will just cause confusion. spend 1-2 hours getting the feel of it and it will increase your repair ability 100x no joke.
How can you verify the arcades game resolution and pixel grid using an oscilloscope? because each arcade game resolution is different with different H&V columns and rows numbers some games are 256X240 and other arcade games are different. How do you measure and verify an arcade games resolution to know the arcade game is 256X240 or something other? Can the Oscilloscope or Logic Analyzer able to count the arcade games H&V to know what the arcade games resolution and pixel grid?
I'm not sure if there is a bad RAM chip or get a DCD error or BTS error only in the RAM region that this will change and alter the ROM signature value to a totally different number can this happen? can a bad ROM chip or getting a DCD error or BTS error on a RAM chip cause the ROM signature value to change and alter to a totally different ROM signature value?
I don't understand why the vertical counters to create the vertical sync signals are being loaded as a default as 7C. Any reasons why the vertical counters in Ms Pac man are starting being loaded at 7C? it doesn't make sense to me. Also when the vertical counter chips have reached FF how does the CPU know when to send the Load pulse to the Vertical counter chips?
But most arcade games Z80 and 6052 CPU use a 16 address lines but the ROM chips are only 11 address lines any reasons why? This is what confuses me is that all the ROM chips 2716, 2732, 2516, 2532, etc are all 11 address line inputs so each ROM chip can only hold up to 2048 address. I would think a 2732 or a 2764 would have more address to hold compared to a 2716 ROM chip, but it seems that a 2716, 2732, 2764 all just only have 2048 address maximum? I might be confused how to calculate using a calculator on how many bits a 2716, 2732, 2764 can hold, how can i calculate using what formula? The maximum address is 2048 but the "amount of bytes per address" might be different for a 2716, 2732, 2764?
I'm not sure if all arcade games have separate TEST ROM chips,
1.) What are the differences between using the arcade games test mode diagnostic test program compared to using a separate TEST ROM chip? You remove one of the ROM chips from the socket and instead a TEST ROM chip. The Test ROM chip does more deeper level ROM/RAM test I'm guessing
2.) Some repair technician say that dual wipe sockets are better than the machine pin sockets. I thought that the machine pin sockets had less intermittent issues and dual wipe sockets cause more intermittent issues.
1) test roms are usually found for games that didn't have test roms built in. some people have written "better" test roms for games that do more stuff.
2) I do not recommend machine pin chips. I like dual wipes for a bunch of different reasons.
@@arcade-cabinets
They have test rom chips for arcade games that have built in test modes also. I'm guessing people have made these AFTER the 80's game programmer.
1.) I wonder why I can't use the same TEST ROM chip for any arcade game because the TEST ROM is doing different types of ROM test and and RAM tests so i would think the TEST ROM chip should work for all arcade games.
What do you think makes the difference in the code that the test rom chip won't work for ALL arcade games?
2.) Can you list why you like dual wipe sockets compared to machine pin sockets?
bill williams different games have different memory layouts. Some chips can be used in Multiple games if the system architecture is the same. In the 80s manufactures often made a platform that could just have different Roms for each game just by swapping Those often can use the same test rom chip. However each game has different code so you cannot have. A single test rom that checked the other Roms only ram and sound and video.
I don’t like machines pins because 1) there legs and connectors are big so it’s hard to solder them in correctly, often people will try to solder them in and overheat things in the process destroying the traces and via’s, or bridge traces.
Then 2) it’s almost impossible to remove them once installed without destroying the traces
3) it’s hard to insert chips in there everything has to be slight perfectly and often pushing them In will break the legs
@@arcade-cabinets ok thanks for the help
1.) So are you saying that the since each arcade game has a different address mapping/address decoding you can't use a single test rom chip for ALL arcade games? or it's not about the address mapping/address decoding?
2.) If a software programmer wanted to make ONE signal test rom chip for all 80's arcade games what would need to be done in general?
@@billwilliams6338 1) yes there's no way of making a single test rom for every single game
2) it's literally impossible.
Do you think you can make Z80, 6505, 8088 complier youtube videos showing how to read the arcade ROM chips and turn the hexadecimal code into instructions and going over the coded game instructions. Like take Pacmans ROM chips and read the hexadecimal code and use a Z80 or 6505 complier to convert the hex code into instruction and go over the instructions of the game code to learn from in the youtube video lesson. Do you know how to do this?
arcade cabinets, I have seen circuit pad jumpers on arcade games for I/O buffer chips, what are they used for?Atari Battlezone N2 and K3 , LS244 , Pin# 1 and Pin#15 have circuit board jumpers, any reasons why?
Some games can be configured to use different chips. I don’t know offhand but I think battle zone could use different buffers depending on what the manufacturer wanted to use at production time. Cost and availability is always a concern for manufactures
Oh ok thanks, so those Circuit Pad Jumpers are mostly used for different pin out chips? Because I have see in arcade games schematics a lot of circuit pad jumpers for RAM chips and ROM chips also which I think ground certain address lines. The control lines and data lines stay the same I think.
When you read an arcade games program ROM chip, there is 16 rows with hexadecimal values. How you know which ones are the Opcode values and which ones are the data values in the Z80 language or 6502 Language? because it will display 16 rows of hexadecimal values for each address offset, but how do you know which ones are opcode values and which ones are data values?
wayne Gram you have to know the machine language specifications. The specifications tell you how to decode each instruction which then you have to do one after another. Some cpus machine languages however are designed to be easy for example each instruction might be exactly 32 bits and x or those are the instruction and y are data values
But when you read arcade ROM chips it will display the Rows and columns of hexadecimal values. The address offset values in the rows and there is 16 columns going across the screen with 2 hexadecimal values per column. Are these only just hexadecimal data or are these hexadecimal values Opcodes values?
arcade cabinets, how do you set your oscilloscope to count the logic data? because I have heard arcade repair technicians doing this to troubleshoot serial & parallel shift registers to "count the data" on the inputs and outputs of shift registers, any reasons why you would want to "count the data" in logic signals? why would you want to count the data for what kind of logic signals in arcade games?
wayne Gram I’m not sure what you are asking. An oscope can count the number of times a signal goes high or low or frequency of a signal but I don’t know what your asking
Some Oscopes will have a counter that "counts every data pulse" the counter will show a value of how many counts the logic pulse is for that logic signal. Most Logic Analyzers I think do this. If you're measuring a clock signal the counter will count every data pulse of the clock signal. What I'm confused about is when would an arcade repair technician ever use the counter to count the data pulses for troubleshooting shift registers or V&H Counters chips?
When an I/O data buss buffer IC chip has one short or open pin it causes ROM signature issues. Any reasons why if only one data buss buffer pin that is either shorted to ground, shorted to +5vdc or open floating can cause ROM errors on the fluke 9010A giving different ROM signature that are correct ROM signature?
I dint understand the question. If it’s giving different signatures (which it should if the buffer is bad) how can they be the correct signature?
@@arcade-cabinets When the Data buss Buffer has one input or output pin shorted to ground or shorted to High +5 or floating, when you type in the ROM signature in the Fluke 9010A it will say there is a ROM signature Error and it doesn't match the ROM signature. I'm confused because the Buffer IC chip should not change the ROM signature even if one input or output pin is shorted to ground, shorted to High or floating. But it seems that the Buffer IC data buss chip can change the ROM signature, but I don't understand why or how it changes the ROM signature.
All arcade games use 2V to 128V and 2H to 128H sync signals. 128V Multiplied by 128H = 16, 384 bits or pixels? Does this mean that all arcade games are 64K pixels?
How does the arcade games MPU Vector Reset affect the address decoder circuit? The 6502 MPU vector reset address, MPU Z80 vector reset address, MPU 8088 vector reset address are all different address values. How does the MPU vector reset address does what to the arcade games address decoder circuit?
The address decoders are not affected by the reset vector. The reset vector is defined by the chip manufacturer and the system must be built around this.
@@arcade-cabinets When you first turn on the arcade game, what is sending a signal to the Reset vector? I thought the arcade games reset circuit or address decoder circuit sends out an address to the MPU to the MPU's reset vector. I'm not sure what the MPU reset vector does or how the watchdog circuit is sending out a pulse to the MPU reset vector.
When reading the game codes contents from an arcade games ROM chip, what assembler can I use to convert the game code into reading the code easier?
Can I load the game codes contents into an assembler and the assembler can convert the game code into reading the code easier and maybe debugging troubleshooting the code?
you need a disassemble for whatever CPU that is used. MAME in debugging mode has a disassembler. Also check out GHIDRA (ghidra-sre.org) it's amazing though a bit complicated to get started with.
BUSACK Bus Acknowledge signal in arcade games is used for what reasons? I'm not sure if the BUSACK is an input or output to the CPU
wayne Gram it’s an input, that allows other devices to request use of the bus. I don’t think I’ve seen it used in arcade games.
@@arcade-cabinets but most ROM and RAM are using the data buss all the time, so I don't get what devices would be sending a BUSACK bus acknowledge signal
@@waynegram8907 ram and rom are not considered independent devices. they are just responding to requests from the cpu they do not try to use the bus on their own.
@@patreonarcades4476 what would use the bus on their own? what devices and IC chips would send out a BUSACK bus acknowledge signal to take over the data buss?
@@waynegram8907 nothing that ive seen on any games, probably something wanting to do DMA
It doesn't make sense to me how the Fluke 9010A can say the ROM signature is OK when the ROM signature is the wrong signature because there is an addressing issue. Why would the Fluke 9010A say its OK when the ROM Signature is the wrong signature? It happen when you have an addressing issue but I would think the Fluke 9010A would say its a bad signature error but it doesn't, any reasons why?
I dont' remember the specifics of this video, but if the addressing circuits where messed up then the fluke signature check should NOT be successful, that said it's possible that the addressing circuit chips etc work OK for the regions that control the ROMs but the parts that control the RAMs are not ok. that would allow the ROM access to be OK, but not the RAMs.
Keep in mind although most addressing circuits are pretty simple they do consist usually of at least 3-5 chips and not all chips are used for all parts of the address range.
If the address circuit chips are OK for the regions that control the ROM why would the ROM signature be incorrect wrong but the Fluke 9010a says OK with no errors? Or what would cause the Fluke 9010a to say the ROM signature is OK but the ROM signature is wrong and incorrect?
That does not make sense? How could the fluke both has ok and say there is errors?
The Fluke 9010A will say its OK but the "ROM signature is wrong" when comparing it to the ROM signatures on the internet. The Fluke 9010A will say that the ROM signature is OK with no errors when the ROM signature is wrong or " just a totally different signature compared against to looking up the Correct ROM signature on the internet. This is my main question is why does the fluke 9010a says the ROM signature is OK no errors but really its the wrong signature? I would think if the address decoder circuit is not working correctly it would make the ROM signature bad but it doesn't because the address decoder circuit or an addressing problem on the arcade games doesn't affect or do anything to the ROM signature it seems. The ROM signature is separate from the address decoder circuit and addressing issues because it has nothing to do with addressing. So the Fluke 9010A will say that your ROM signature is good and OK when actually its wrong compared to the internets ROM signature for that arcade game. I'm not sure why the Fluke9010A is saying its good and OK when the ROM signature is incorrect or "is totally a different signature" but the Fluke 9010A will say its OK and good. I'm not sure what causes the ROM chip to output totally different ROM signatures but I don't think the address decoder circuit or is the address buss has shorts or floating lines would this change the ROM signature to a totally different rom signature value?
ARCADE CABINETS,
the FETs or Cells inside the 4116 dram needed +/- 5 and +12 because of what reasons to store the data bit? because 4164 are Dram also but the cells fets only needed +5vdc to store the data bit, why?
I have no idea, I'm not an electrical engineer. that would be a question for the people who designed the chip way back when.
@@arcade-cabinets ok thanks
@@arcade-cabinetsThanks for the help. Not sure if you know the answer to this but For Bally midway Galaga they used a custom sync generator chip i'm guessing for the V&H sync counter chips are built inside this custom sync generator IC chip. How does the Sync Generator chip work, what does it do?
@@billwilliams6338 basically what you said, they just made a chip that combines a bunch of other chips/logic into a small single chip. Namco used this chip on a bunch of games so it was probably cheaper to just make a custom chip that had the counters and some other functionality than to use the space on the board and a bunch of other chips.I don't know all the functionality that this chip does but it certainly handles timing as well as data buffers.
@@arcade-cabinets oh ok thanks I wasn't sure what the chip had inside of it.
ARCADECABNIETS< I'm confused on the video sections in arcade games from the differences of Raster arcade games compared to Vector arcade games. Raster arcade games use Horizontal and Vertical sync signals for the CRT positioning coordinates and uses a Color PROM chips to choose which colors tints etc. Vector games don't use H&V sync signals but uses Deflection signals. I don't know what the differences are between H&V Deflection signals compared to H&V sync signals. What are the differences between H&V sync signals compared to H&V Deflection signals or are they the same thing? Vector arcade games don't use a Color PROM chips like Raster arcade games? In Raster arcade games the game board outputs an RGB signal with V&H sync signals which is 5 separate wires to the CRT monitor board? In Vector Arcade Games the game board outputs H&V Deflection signals and RGB signals to the CRT monitor board?
bill williams: honestly I have no idea how vector monitors sync or if they even have a concept such as such. I don’t usually mess with vectors. I thought vectors just draw/deflect the beam as needed using a +/- charge on each axis as needed but I could be wrong, I never mess with vector video hardware honestly so I could not really say with any certainty.
@@arcade-cabinets ok thanks i thought maybe you knew about arcade games in the 80's that were vector and not raster because some arcade games in the 80s were vector
@@arcade-cabinets what would be the "Equivalent" to a "DMAGO signal" in an arcade raster game non-vector game?
@@billwilliams6338 I don't know of any raster games that have anything like that honestly. I think it was just a Atari vector oddity. (DMA is NOT an Atari vector oddity) but the whole vector video circuit halting the CPU , I cannot say I've seen on anything but Atari vectors. (and I"ve only seen vectors that are Atari, maybe other vectors do to but I don't know)
-brian
@@arcade-cabinets ok thanks
every arcade games in the 80's had separated address decoding circuits for the video hardware, video RAM, video ROM chips. I don't understand why they made the separated address decoding circuits for the video circuits to not be able to be accessed by the CPU to read and write to the video circuits, video RAM, video ROM, any reasons why they did this? and not use the same address decoding circuits for the game code why have a separated address decoding circuit for only the video sections?
Leaded solder, nice heavy. If you hold your board vertically, the sucker won't have such a hard time to work against gravity.
How do you calculate using a calculator formula the maximum data bits that a single ROM chip can hold? 2516 ROM or 2532 ROM chip how can you calculate the max data bits that it can hold
2 to the power of the number of address lines. if there are 11 address lines it's 2^11 or (2x2x2x2x2x2x2x2x2x2x2) = 2048 and these are the number of bytes. for exapmle a 2716 or 2516 has 11 address lines (a0 - a10) so it has 2048 addresses each holding 1 byte of data.
When testing a ROM chip and you didn't have the signature value. When you type in the ROM start range and ending range on the Fluke 9010A and "enter in signature 0 value", you will get an error message when you press the MORE button which the fluke 9010A will tell you what the ROM signature value should be
1.) How does the Fluke 9010A know what the ROM signature value should be?
2.) This can be a way of cheating by get the ROM signature value without knowing it?
3.) When you REMOVE the ROM chip from the socket the Fluke 9010A will tell you a ROM signature value any reasons why?
1) the fluke knows how to compute the checksum. its in the flukes code.
2) assuming your game is working correctly, yes that is a way of determining what the signature should be, it only works if your sure your game is working though!
3) Because the CPU always sees "something" if the ROM chip is not there usually it shows up as 0xFF for each address that you read.
@@arcade-cabinets thanks for the help
1.) But how does the fluke compute the checksum even when you have entered in the wrong ROM Signature value?
2.) When removing the ROM chips from the sockets the fluke 9010A will give you a ROM signature value that is a different ROM signature value compared to when the ROM chip is installed in the socket. Why is there two different ROM signature values?
Arcade games use counter chips with a carry in and carry out, I'm not sure why would you want to use the carry in and carry out because it changes a 4 bit output counter to a 5 bit output counter. The carry in and carry out changes the counters output value, but not sure when arcade games use the carry in and carry out for what reasons?
Ms pacman has a custom IC chip that interfaces the game ROM chips and RAM chips with the character RAM chips and sprite RAM chips. The Fluke 9010A can read and write to the character and sprite RAM chips with the Customer IC chips Removed. When the Custom IC chip is Remove why can't the game ROM chips and RAM chips able to talk with read and write with the character ram chips and sprite ram chips?
That's not correct the game ROM chips and RAM chips never talk to sprite RAM or ROM. RAM and ROM cannot initiate transfers of data they can only respond to requests from the CPU or the video hardware.
What does the Ms Pacmans Custom IC chip purpose? its ment to interface the hardware with the sprite RAM and character RAM?
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