Board issue, need some advice!

mikdawg

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I have a John Elways Qb that I am working on. It has two issues.

1. The game rams all check out ok, according to the system check, but the game freezes every 15 sec or so for about 3 sec long and then continues to play. Any clue why or how to fix this problem?

2. It also has no sound. I went to the audio subsystem test and it reads that the audio processor is not repsonding. Where is this processor (on the board) and can it be fixed?

Thanks for the replies,

Greg
 
I have a John Elways Qb that I am working on. It has two issues.

1. The game rams all check out ok, according to the system check, but the game freezes every 15 sec or so for about 3 sec long and then continues to play. Any clue why or how to fix this problem?

2. It also has no sound. I went to the audio subsystem test and it reads that the audio processor is not repsonding. Where is this processor (on the board) and can it be fixed?

Thanks for the replies,

Greg

I always check the power supply before doing anything else. Even when I setup a test rig and plug it in. I bought a cheep analog meter to watch for voltage spikes and drops.

Most problems with the pcbs can be fixed but parts are becoming harder and more expensive.

I have not looked at the schematics for that game but most games I have worked on have a processor for the sound and that is a good place to start to look at, After you verify the sound (audio) amp is getting voltage and is working.

Another thing you might look into is the ram chips. If there are several different type and speed ram chips, that will cause problems too. You can go faster but not slower.
 
I am going to replace the power supply, it is the original one. That makes sense to me why it was freezing. What does the audio processor look like or where would it be located? Is it a chip that is soldering into the board?
 
I am going to replace the power supply, it is the original one. That makes sense to me why it was freezing. What does the audio processor look like or where would it be located? Is it a chip that is soldering into the board?

I found some info about this game for you.....


http://arcarc.xmission.com/PDF_Arcade_Manuals_and_Schematics/John Elways Team Quarterback.pdf

I just did a quick look at this and looks like many other games of that time with z80cpu processors and a 2002 sound amp. that requires +12volt to work properly.
 
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Absolutely no point replacing the power supply if you haven't determined that the existing one is faulty.

The sound CPU is (unfortunately) an 80186. It won't be easy to find a replacement if there is actually something wrong with it, it's just as likely there's a fault with the logic controlling it.
 
Absolutely no point replacing the power supply if you haven't determined that the existing one is faulty.

The sound CPU is (unfortunately) an 80186. It won't be easy to find a replacement if there is actually something wrong with it, it's just as likely there's a fault with the logic controlling it.

+1

probably the dac is the problem but you need to test it with logic probe or scope to be sure.
 
I was thnking about buying another board to swap out parts if needed. Will I be able to do that?

Most parts will be soldered in there and unless you have a good rework station then NO. The sound problems are easy enough to fix with a little detective work.

It is always helpful to have a working board to test points with a scope then test the same points on the bad board. If you can find a replacement board cheep, then I would get it to help with the repair of the bad board and you have a spare.
 
It's not the DAC because the board reports that the audio CPU is not responding. From what I can make out from the poor resolution pictures available, the audio section is on the top board, try reseating that and all relevant connectors.

If that doesn't make an improvement, then it would be worth trying another CPU if you could find one cheap (assuming the existing one is socketed).
 
It's not the DAC because the board reports that the audio CPU is not responding. From what I can make out from the poor resolution pictures available, the audio section is on the top board, try reseating that and all relevant connectors.

If that doesn't make an improvement, then it would be worth trying another CPU if you could find one cheap (assuming the existing one is socketed).

If the problem is on the top board you might try to find just that board and save some money. It can be a cpu chip but I would look at voltages and connections first, if the voltages are low it will do screwy things. Look over the connections and use a meter to verify they are making contact.
 
I threw a new power supply in there for fun and had no changes. I took out the boards and tomorrow i will reseat the chips. The game has been sitting for awhile so that might help. Will let you know. Thanks for the help.
 
Well, the voltage is perfect in the game with the new power supply. I reseated and cleaned all of the chips on the board. Still no sound and game is still pausing. I did find one prong on a chip that was broken off. How much of an effect will that have on the game? Any advice?
 
Well, the voltage is perfect in the game with the new power supply. I reseated and cleaned all of the chips on the board. Still no sound and game is still pausing. I did find one prong on a chip that was broken off. How much of an effect will that have on the game? Any advice?

can be why the game is not working. I would solder a donor leg to the chip and re seat and test. What are the numbers on the chip and can you post a pic of it??
 
It is at my house, I will get the numbers and a pic for you. What should I use for a donor leg? I really do not have any extra chip laying around. Just any metal?
 
It is at my house, I will get the numbers and a pic for you. What should I use for a donor leg? I really do not have any extra chip laying around. Just any metal?
I'd buy a cheap chip from a local electronics shop. In the past I've used other things like resistor leads and I've found them to be unreliable.
 
Ok, the broken leg on the chip is half of the small leg. The chip reads 1988 leland corp. P/N 03-15622-01 Team QB U15T (not sure what this chip is responsible for).

Also, I checked the +5 test point on the front board and it was good. On the second board, I could not find a ground pin to test them with. There are 7 test point. I used the first boards ground pin and got nothing? Is there a better or right way to check these test points?
 

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Ok, the broken leg on the chip is half of the small leg. The chip reads 1988 leland corp. P/N 03-15622-01 Team QB U15T (not sure what this chip is responsible for).

Also, I checked the +5 test point on the front board and it was good. On the second board, I could not find a ground pin to test them with. There are 7 test point. I used the first boards ground pin and got nothing? Is there a better or right way to check these test points?

That looks to me like a prom but not sure I haven't looked it up in the schematics. If it is a prom they are usually used for the sound. They need to be programmed if you replace it.

You can use just about any ground and I usually use one at or near a cap, top or bottom board shouldn't matter. If you are not getting any voltage to the top board, that is a problem that needs to be looked at first.
 
According to the schematics, the chip is on the slave CPU. What does that mean?

I have voltage to the top board but it is the board under that one that may have an issue. I will double check it tonight.
 
According to the schematics, the chip is on the slave CPU. What does that mean?

I have voltage to the top board but it is the board under that one that may have an issue. I will double check it tonight.

Kind of like what the name implies. That is the cpu that does all or most of the work and if it is a zlog chip I rip it out like a bad tooth. They become iffy and cause several different problems and they are not too expensive to replace. Put a socket in is also a good idea and can come in handy to test the logic.
 
Ok, the broken leg on the chip is half of the small leg. The chip reads 1988 leland corp. P/N 03-15622-01 Team QB U15T (not sure what this chip is responsible for).

That's an EPROM. A 27C512 specifically. It is used by the audio CPU. It's listed in the MAME driver as follows:

Code:
ROM_LOAD16_BYTE( "15622-01.15t", 0x0e0000, 0x10000, CRC(9e84509a) SHA1(4c3a3e5192ba6c38d8391eedf817350795bddb8f) )
 
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