wugly
Well-known member
your problem with d2 pin 1 is probably corrosion but it should be identical to e2 pin 1 is an input
-
Please post all monitor technical topics in the Technical - Videogames - Monitors section, not in the General Help section.
Another Space Invaders sound issue
- Thread starter N24005
- Start date
- Joined
- Jan 12, 2024
- Messages
- 48
- Reaction score
- 12
So F3-13 (low) pulsing should cause F3-12 to pulse (high) which should cause E3-7 to pulse which should cause D2-1 and E2-1 to pulse which resets the watchdog counters which prevents D2-9 and E2-9 from going high, signaling the cpu to reset.
I'm still a bit confused. CPU-12 is the reset. It should be low unless a reset is requested by going high.
That means D2-9 and E2-9 (^load) must stay low?
In any case, I am not seeing F3-13 pulse at all today. It is rock solid low. (Don't know if I was on the wrong pin before or what)
With F3-13 staying low, F13-12 will stay high and the watchdog will bark. F3-13 appears to be the 'sample' line coming from the motherboard at edge connector 31.
This is fed off A4-6 which is steady low. A4-4 (BX-6) and A4-5 are both high
E4-6 (BX-5) is low buzz
E4-5 (CPU-18) is a high buzz
D7-10 (BX-4) seems to stay low while running but pulses when the program restarts. The manual says it should be pulsing while the cowboy moves in and out…. The manual says to check pin 10 (which should be low) and pin 11 (but it doesn't indicate its state…). Hmmmm
It looks like D7-11 is coming from the data bus. It does have a variety of signals.
So my best guess is that the 74174 at D7 is holding pin 10 low. I'll replace that and see what happens
I'm still a bit confused. CPU-12 is the reset. It should be low unless a reset is requested by going high.
That means D2-9 and E2-9 (^load) must stay low?
In any case, I am not seeing F3-13 pulse at all today. It is rock solid low. (Don't know if I was on the wrong pin before or what)
With F3-13 staying low, F13-12 will stay high and the watchdog will bark. F3-13 appears to be the 'sample' line coming from the motherboard at edge connector 31.
This is fed off A4-6 which is steady low. A4-4 (BX-6) and A4-5 are both high
E4-6 (BX-5) is low buzz
E4-5 (CPU-18) is a high buzz
D7-10 (BX-4) seems to stay low while running but pulses when the program restarts. The manual says it should be pulsing while the cowboy moves in and out…. The manual says to check pin 10 (which should be low) and pin 11 (but it doesn't indicate its state…). Hmmmm
It looks like D7-11 is coming from the data bus. It does have a variety of signals.
So my best guess is that the 74174 at D7 is holding pin 10 low. I'll replace that and see what happens
Attachments
wugly
Well-known member
d2p and e2 9 are not reset but bar reset which is the invert of reset. its used to reset things on sound board.
wugly
Well-known member
are you doing these readings with the test rom chip in?
- Joined
- Jan 12, 2024
- Messages
- 48
- Reaction score
- 12
Motherboard D7 replacement didn't help. Pin 10 is still always low, while the Midway 8080 test manual says it should be pulsing.
D7-11 is pulsing
What else could be drawing 10 down? Are the yellow and orange circled areas connections or crossovers? It's hard to tell on these grainy copies. It looks like orange is a connection while yellow are not.
And this shows that Pin 10 is the status SD4 on pin 24 of the daughter board connector. But I can't find any reference to this pin or data on the daughter board. Does it do anything for a SI daughter board?
D7-11 is pulsing
What else could be drawing 10 down? Are the yellow and orange circled areas connections or crossovers? It's hard to tell on these grainy copies. It looks like orange is a connection while yellow are not.
And this shows that Pin 10 is the status SD4 on pin 24 of the daughter board connector. But I can't find any reference to this pin or data on the daughter board. Does it do anything for a SI daughter board?
Lurch666
Well-known member
Neither orange or yellow are connected.
wugly
Well-known member
hopefully you used a socket and can pull pin 10 out of the socket and measure the pins responses with it not hooked into the rest of the board. want to also verify on pin 11 signal
- Joined
- Jan 12, 2024
- Messages
- 48
- Reaction score
- 12
Back at it after a break….
Test rom running on Midway SI boards, power verified. Cocktail cabinet.
RAM test passes, CRC correct on E,F,G
Inputs display looks a little funny. Port1-0 and Port2-1 don't have asterisks. Watching videos of others it seems like they should..
Port1-3 and Port2-3 don't either, which seems normal. All others do.
The program will often reset during the sound test, and sometimes before, but it occasionally makes it to the shifter test, which fails. Rows 5-8 have an error.
From my reading, it appears that one of the shifters is not storing the data written to it. I'm thinking it is the 25S10 at C4, but I would love a confirmation of that.
That said, I don't see the 25s10 in the 4th row of the daughter board, but rather 74LS151s. I'm missing something…
Actually since it seems that d4-d7 don't seem to be getting to the shifter, the one common chip for these lines is the 8216 @ B3 on the motherboard. I'll take a closer look at that with the logic probe.
Again, the reset can happen anytime while running the program and sometimes never. Pin 12 on the CPU is low until something drives it high…
Test rom running on Midway SI boards, power verified. Cocktail cabinet.
RAM test passes, CRC correct on E,F,G
Inputs display looks a little funny. Port1-0 and Port2-1 don't have asterisks. Watching videos of others it seems like they should..
Port1-3 and Port2-3 don't either, which seems normal. All others do.
The program will often reset during the sound test, and sometimes before, but it occasionally makes it to the shifter test, which fails. Rows 5-8 have an error.
From my reading, it appears that one of the shifters is not storing the data written to it. I'm thinking it is the 25S10 at C4, but I would love a confirmation of that.
That said, I don't see the 25s10 in the 4th row of the daughter board, but rather 74LS151s. I'm missing something…
Actually since it seems that d4-d7 don't seem to be getting to the shifter, the one common chip for these lines is the 8216 @ B3 on the motherboard. I'll take a closer look at that with the logic probe.
Again, the reset can happen anytime while running the program and sometimes never. Pin 12 on the CPU is low until something drives it high…
Attachments
Last edited:
wugly
Well-known member
before you go too far make sure the two boards are able to connect between the interconnect connectors
wugly
Well-known member
the ports that are being displayed will change as you push control buttons and change the dip switches on the game board. the ports just tell you if the corresponding control is registering to the game board
wugly
Well-known member
need to see picture of your board to figure out which version you have
wugly
Well-known member
oh its a regular. I am looking at a few si threads and now I know exactly which schematic you are using. in my head you had a deluxe. mostly the same. this 151 on the 4th row what is the letter of it and can you show me a picture of it and the general area
wugly
Well-known member
this is a schematic for the shifter but I have no idea where the layout of the chip positions are on your board. this is going to be an interesting problem to troubleshoot. you do not have the standard shift ic but you have the non standard 151 chips. I would start looking at the 151 with a logic probe and look for stuck pins
- Joined
- Jan 12, 2024
- Messages
- 48
- Reaction score
- 12
Looking at the 74-174s and 74-175 where D0-D7 interface with DS0-DSF…
All data lines have activity, however, all DS lines are solid low.
Pin 9 (clock - port 4) are all high, while pins 1 (^reset) all have signal high.
Looking at the data sheet, if the clock is stuck high or low, then the input has no effect on the output. Hmmmmm
Looks like E3-7 (7442 output 6) drives that from pins 12-15. Pin 12 is always high so 7 will always be high. (If this noob is reading it correctly)
Should Port 4 be high? This is also tied to D2-1 and E2-1 (clears counters)
Thanks!
All data lines have activity, however, all DS lines are solid low.
Pin 9 (clock - port 4) are all high, while pins 1 (^reset) all have signal high.
Looking at the data sheet, if the clock is stuck high or low, then the input has no effect on the output. Hmmmmm
Looks like E3-7 (7442 output 6) drives that from pins 12-15. Pin 12 is always high so 7 will always be high. (If this noob is reading it correctly)
Should Port 4 be high? This is also tied to D2-1 and E2-1 (clears counters)
Thanks!
Attachments
wugly
Well-known member
clock rising triggers the flip flop. reset which is triggered by the watchdog coming off port 6 should be low during program run which mean bar reset is the invert of reset and should be high. port 4 should not be tied to bar reset, if it is that is your problem. could be a trace jump or an internal short in the ic. are any of the chips we are talking about socketed? asking because if they are we can lift a pin out of socket to test things. I am thinking control signal to 174 and 175 might be problem from your description. on the 151 shift schematic can you give me the chip label number for the board position you are referring too so I don't spend the extra time trying to interpret which chip you are talking about
