Spyhunter garbage on screen

dyno

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Spyhunter no 5v on reset line

Finally got the MCR power supply on my spyhunter working and now I am getting garbage on the screen. The picture is mostly yellow with a bit of red and when I try to coin it up I get nothing. I noticed that the led on the spyhunter pcb is not lite up and when I press the red test button on the board it does not do anything. Also none on the the lights seem to be working and there is a seperate board that has an led it on it also and it is not lite up and does nothing when I press the test button on that board. I have 5V and 12V coming off the pwer supply to the mani board. Any ideas?
 
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on mine, one of the ribbon cables was bad. i dont know which one as i just made new ones and that fixed it

hopefully thats what wrong with yours as thats relatively an easy fix
 
Under normal operating conditions, the LED on the board stack DOESN'T light. Have you checked the reset signal? Spy Hunter needs it. On the power supply board, one of the two larger connectors has a purple wire leaving it. That's the reset line. Set meter to DC volts. Stick the red probe around the purple wire into the connector housing (make sure it's touching the metal pin)...black probe to ground (the negative side of the cap beside of the two connectors works good). You should see 5VDC (give or take).

Edward
 
on mine, one of the ribbon cables was bad. i dont know which one as i just made new ones and that fixed it

hopefully thats what wrong with yours as thats relatively an easy fix

Splatter, just out of curiousity what did you make your cables from?
 
I tested the purple wire like you said and am not getting anything, the meter reads .02, tired a few times to make sure I was doing it properly an got nothing. So I guess I should look for a problem on the reset circuit on the power board?
 
I also tested the orange wire going into from the power supply to the main board, at the harness going into the main board and it is suppose to be 12v but is only showing 3.5v going into the main board.
 
I also tested the orange wire going into from the power supply to the main board, at the harness going into the main board and it is suppose to be 12v but is only showing 3.5v going into the main board.

There's a cap in the middle of the power supply board...470µf. Measure the voltage across it. This is your 12VDC rail. Meter's black lead to the ground side of the cap....red lead to the positive side. See what you get.

Also, it sounds like it's time to dig into the reset circuit.

Edward
 
I measured the cap with everything unplugged and was still getting only 3.5v, then I realized I forgot to unplug the coin door and once I did that the voltage when up to 12v. I plugged everything back but the coin door and checked the voltage and now is was around 11.22v, tried to adjust it but it wouldn't go higher, I unplugged the cheap squeak board and the voltage went up to 12v again. Plugged the squeak board back in the voltage went down to 11.22v, with everything plugged in should the voltage stay at 12v or is it normal for it to be around 11.22v because of the power draw from everything or does it have to be 12v for all to work normally. If that is a problem what would cause the voltage to not stay at 12v or be able to adjust it higher than 11.22v.
 
Should I be thinking of buying the MCR power supply repair kit from Bob Roberts, will that help here and if I do go that route should I even buy the SCSI ribbons and replace the ribbons on the main board while I am at it?
 
I measured the cap with everything unplugged and was still getting only 3.5v, then I realized I forgot to unplug the coin door and once I did that the voltage when up to 12v. I plugged everything back but the coin door and checked the voltage and now is was around 11.22v, tried to adjust it but it wouldn't go higher, I unplugged the cheap squeak board and the voltage went up to 12v again. Plugged the squeak board back in the voltage went down to 11.22v, with everything plugged in should the voltage stay at 12v or is it normal for it to be around 11.22v because of the power draw from everything or does it have to be 12v for all to work normally. If that is a problem what would cause the voltage to not stay at 12v or be able to adjust it higher than 11.22v.

It should stay at 12 volts with everything plugged in.

1st: The coin door lights......something is shorted. My initial thought is one or both lamp sockets have a short. Also, I've only seen it twice....I've had bulbs go bad in such a way they short.....or else the wiring going to the coin door has been pinched and causing a short.

2nd: The cheap squeak board...that's not a big drop....kinda strange. Something on that board is pulling it down....or you've got a filter cap in the 12VDC circuit that is nearing the end of it's life....and the cheap squeak board is enough of a current draw to drop the voltage. Honestly, 11VDC is probably enough to run the game properly.....but it's not a good sign for the future.

Edward
 
I have plugging awat at the reset circuit but with no luck, looking at the schematics there are pionts where 5v is coming in and they all seem good but when at the end od the line at the pruple wire all Iam getting is .02v still. I tested the transistor at the end of the line right before it does to the purple wire and the transistor is good. There is some minor corrosion from the old battery but I don't think that is the problem. So far everything I have checked seems good but no 5v coming off the mcr power board for the reset line.
 
I have plugging awat at the reset circuit but with no luck, looking at the schematics there are pionts where 5v is coming in and they all seem good but when at the end od the line at the pruple wire all Iam getting is .02v still. I tested the transistor at the end of the line right before it does to the purple wire and the transistor is good. There is some minor corrosion from the old battery but I don't think that is the problem. So far everything I have checked seems good but no 5v coming off the mcr power board for the reset line.

On a couple occasions, I've has that transistor test good with my meter...but actually be bad. Some other likely culprits...the LM3900, and the 4N28 opto isolator.

Edward
 
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I was actaully wondering maybe if the transistor is bad even thought it is testing good, and was wondering if maybe the lm3900 and the 4n28 opto isolator might be bad. I will test those wiht my logic probe and see what it shows. Do you think it is worth buying bob roberts repair kit ot just buy the parts individually? There are some parts in Bob's kit that are testing good on my board so I don't know if I need the entire kit.
 
I was wondering can I substitue a ceramic disk capacitor for an axial ceramic capacitor as long as the value is equal? The reason I ask is that I have a bunch of ceramic disk caps at home.
 
I was actaully wondering maybe if the transistor is bad even thought it is testing good, and was wondering if maybe the lm3900 and the 4n28 opto isolator might be bad. I will test those wiht my logic probe and see what it shows. Do you think it is worth buying bob roberts repair kit ot just buy the parts individually? There are some parts in Bob's kit that are testing good on my board so I don't know if I need the entire kit.

You'll need a scope for the 4N28.....probably the LM3900, too. If you've got 12VDC and 5VDC....I don't think you need Bob's kit. You could just buy the transistor and the two ICs from Bob....or Mouser....or any of the other supply houses. Those three things arn't hard to find.

And the cap question...yes.

Edward
 
Got spyhunter running at least temporarily. Found a webpage regarding MCR power supply boards and it said to remove the 2N4401 transistor at Q201, which is part of the reset circuit and that doing so it should get the game running. So I did just that and the game is now working, I am getting 5v to the pruple wire coming from the reset line. I have ordered a new 2N4401 for Q201 so when that arrives I will put it in and see what happens and I have ordered some other parts for the MCR power supply board. Just wondering if not having the 2N4401 on the board can cause any damage to MCR power supply or the mani CPU. I only had it ther game on for a short time with the 2N4401 out, I just wanted to see if that trick worked and to make sure that the main CPU was working.
 
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