track and field low 12v

GoneMad

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I just plugged in a track and field I picked up. Not starting. Upon checking the voltages at the harness, the 12v is actually around 7.5-8V. When I check the PS, it hits about 11 for a split second then drops to around 7 or 8. This a failing PS? I don't see any adjustments on this.
 
Found another power supply and tried it. Getting all the proper voltages across the harness. Still dead. No noise when I adjust the sound pot and nothing when I coin it up. Monitor is good and tested working. First time I have come across one of these boards. Can anyone help me where to start at this thing. Thanks.
 
Found another power supply and tried it. Getting all the proper voltages across the harness. Still dead. No noise when I adjust the sound pot and nothing when I coin it up. Monitor is good and tested working. First time I have come across one of these boards. Can anyone help me where to start at this thing. Thanks.

The sound amp is usually a good place to start. I would bet the sound amp is shorted and pulling the +12 down. If it is not the sound amp then it may be the filter caps or voltage regulator, if that board has one.
 
The sound amp is usually a good place to start. I would bet the sound amp is shorted and pulling the +12 down. If it is not the sound amp then it may be the filter caps or voltage regulator, if that board has one.
It has a low 12v without the harness hooked up. Even the -15v on the power supply is low. After replacing the power supply with another and confirming proper voltages at the edge connector it will not start.
 
It has a low 12v without the harness hooked up. Even the -15v on the power supply is low. After replacing the power supply with another and confirming proper voltages at the edge connector it will not start.

Well now that is different. Usually boards only need the +5 voltage and the voltages for the ram chips to start. They don't usually need the +12 to start, some do but most times it is just for the sound.

Measure the +5 volts at the ttl chips and report back. Try a 16 pin chip and measure pint 8 (gnd) to pin 16 (+5). You should have at least 4.90 to 5.15 volts for the board to even consider running.
 
Well now that is different. Usually boards only need the +5 voltage and the voltages for the ram chips to start. They don't usually need the +12 to start, some do but most times it is just for the sound.

Measure the +5 volts at the ttl chips and report back. Try a 16 pin chip and measure pint 8 (gnd) to pin 16 (+5). You should have at least 4.90 to 5.15 volts for the board to even consider running.
OK, thanks. I just took the boards apart to see if there was anything obvious that was causing this. I will check this once I get it back together.
 
Well now that is different. Usually boards only need the +5 voltage and the voltages for the ram chips to start. They don't usually need the +12 to start, some do but most times it is just for the sound.

Measure the +5 volts at the ttl chips and report back. Try a 16 pin chip and measure pint 8 (gnd) to pin 16 (+5). You should have at least 4.90 to 5.15 volts for the board to even consider running.

Alright. I just went and tried about a dozen random chips on both boards and readings approx. 4.95V on all. Across the harness is about 5.1V and 12.3V, so these seem good.
 
Alright. I just went and tried about a dozen random chips on both boards and readings approx. 4.95V on all. Across the harness is about 5.1V and 12.3V, so these seem good.

Yes,

Them is good and that is a fine start. You have verified the voltage at the chips. Now check to make certain all of the connections from power supply to pcb is correct and clean the connections while you are there.
 
Yes,

Them is good and that is a fine start. You have verified the voltage at the chips. Now check to make certain all of the connections from power supply to pcb is correct and clean the connections while you are there.
Thanks. I will do this. Great advice in your sig. If I would have looked at that first, the subject would have been different. It's a pain in the hoop as I lost my internet connection in the shop and have to resort to coming into the house.
 
Thanks. I will do this. Great advice in your sig. If I would have looked at that first, the subject would have been different. It's a pain in the hoop as I lost my internet connection in the shop and have to resort to coming into the house.

I understand, the public library here had a power loss. We are back up now.
 
Pretty sure that the only things that T&F uses 12V for is the coin counters and the audio amp. So, it's lack (or something pulling it down) may be a problem... it's not a problem that would cause the PCB to fail to boot. (Unless the power supply is designed such that excessive load on the 12V line effects the 5V supply...)

So, with an apparently dead PCB (with a good voltage supply)... consult the sticky thread. It has lots of good info for this situation.
 
I went to go over some of the chips on this board but three of the large chips have the printing ground off them, making them unidentifiable. Does someone have one of these boards and can tell me what the large cpu like chips are in row 3 and 9 of the small board and row 6 of the large board. Thanks.
 
What does the board do? It's difficult to try and diganose a problem when all you've got is the board is "not starting".

Can you post a picture of the screen? Do you have a logic probe or an EPROM programmer?
 
What does the board do? It's difficult to try and diganose a problem when all you've got is the board is "not starting".

Can you post a picture of the screen? Do you have a logic probe or an EPROM programmer?
It does not boot. Nothing on the screen and no sound or hum from the speaker when the volume pot is adjusted. I do have a logic probe and I do have a EPROM programmer. Voltage is good on the pcb from the harness. My big problem is that I have next to no experience with a logic probe. I can get a pic of the screen, but it's black and brightens was the screen knob is adjusted, as if no pcb was hooked up.
 
I went to go over some of the chips on this board but three of the large chips have the printing ground off them, making them unidentifiable. Does someone have one of these boards and can tell me what the large cpu like chips are in row 3 and 9 of the small board and row 6 of the large board. Thanks.

The printing was removed at the factory on most, if not all, of those boards. Most of them are custom chips and RAMs, but the CPU is likely also scratched off, too. See the commends in the MAME driver for more info: http://mamedev.org/source/src/mame/drivers/trackfld.c.html With that map, you should be able to identify which 40-pin ICs is the Konami1 (custom CPU).
 
consult the sticky thread. It has lots of good info for this situation.

It does not boot. Nothing on the screen and no sound or hum from the speaker when the volume pot is adjusted. I do have a logic probe and I do have a EPROM programmer. Voltage is good on the pcb from the harness. My big problem is that I have next to no experience with a logic probe. I can get a pic of the screen, but it's black and brightens was the screen knob is adjusted, as if no pcb was hooked up.

Have you read the sticky thread in this section? Specifically post #2 (not to imply that the rest of the thread isn't worth the time to read)? Specifically the section headed "Things to check on your dead board" (not to take away from the rest of that excellent post)?
 
Have you read the sticky thread in this section? Specifically post #2 (not to imply that the rest of the thread isn't worth the time to read)? Specifically the section headed "Things to check on your dead board" (not to take away from the rest of that excellent post)?

Yes. I have read the sticky. That is why I was asking if someone knew what the chips were that were grinded off. With proper voltage going to the ttl chips, I was suspecting clock or cpu issues as stated in #4 of the dead pcb section. I have no schematic for this yet so am just looking for a little help on the basics, hoping there might be an obvious problem. I also forgot to note that the battery section looks very good as well. There does not seem to be any signs of corrosion or anything. I wanted to identify the cpu chip and thanks to your previous link, it's a z80 cpu, or is it also custom? Thanks so far
 
Yes. I have read the sticky. That is why I was asking if someone knew what the chips were that were grinded off. With proper voltage going to the ttl chips, I was suspecting clock or cpu issues as stated in #4 of the dead pcb section. I have no schematic for this yet so am just looking for a little help on the basics, hoping there might be an obvious problem. I also forgot to note that the battery section looks very good as well. There does not seem to be any signs of corrosion or anything. I wanted to identify the cpu chip and thanks to your previous link, it's a z80 cpu, or is it also custom? Thanks so far

Just making sure. There's good stuff in that sticky, and I quickly tire of repeating/paraphrasing it.

Actually, the Z80 is the sound CPU. The main CPU is a "Konami1", which is a custom version of a 6809.

No scematics? Well that's an easy problem to solve. Last two pages of the manual: http://arcarc.xmission.com/PDF_Arcade_Manuals_and_Schematics/Track and Field.pdf

The reset pin on a Konami1 is 19. Clocks are on pins 15 & 17. I highly recommend the Super Basketball schematics, which show a Konami1 CPU and a standard 6809 wired side-by-side (that PCB was designed to allow either to be installed). So it shows all the corresponding pins.
 
Ahh, I see now. I was under the impression the z80 was main, as getting into the hobby as a noob, the only z80 I have come across was on a pac. Never assume eh? My double dragon uses a 6809E which I am a little familiar with. I will check that out.

Edit: I was just poking around the cab a little bit and found something strapped up under the CP. A brand new manual along with the schematics of the sound board, the cpu board, and also the power supply board. And one or two others, not sure what to though.

Just making sure. There's good stuff in that sticky, and I quickly tire of repeating/paraphrasing it.

Actually, the Z80 is the sound CPU. The main CPU is a "Konami1", which is a custom version of a 6809.

No scematics? Well that's an easy problem to solve. Last two pages of the manual: http://arcarc.xmission.com/PDF_Arcade_Manuals_and_Schematics/Track and Field.pdf

The reset pin on a Konami1 is 19. Clocks are on pins 15 & 17. I highly recommend the Super Basketball schematics, which show a Konami1 CPU and a standard 6809 wired side-by-side (that PCB was designed to allow either to be installed). So it shows all the corresponding pins.
 
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