Gorf video and sound problem

retroshaun

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Hey guys

I have a Gorf video issue - see video below. The screen is flickering and going garbled mosty of the time (worse on the first wave where theres a lot of color). Also a few of the sounds arent working (player shot for example).

I do have a spare board set thats tested as working, but wondered if the video issue is a monitor problem?

Thanks for any pointers.

https://www.youtube.com/watch?v=WX8FNVRrTZ0&feature=youtu.be
 
Looks like a monitor issue to me. I would start by checking the input header on the chassis. It most likely has cracked solder joints.
 
His sounds aren't working either though. I agree that does look like a monitor problem in the video. He may have multiple problems. Do you have a picture of how you currently have everything hooked up?
 
His sounds aren't working either though. I agree that does look like a monitor problem in the video. He may have multiple problems. Do you have a picture of how you currently have everything hooked up?

Right thats what confused me as the 2 problems appeared simultaneously.

I can get a pic once I can either find the keys or drill the lock, hopefully tomorrow. Everything has been fine with the game for years.
 
That's very odd. Maybe check solder joints for the ground coming from the tube? as for the sound have you tried cleaning the legs of the eproms and putting them back in? I haven't seen one of these boards before so I don't know what part of the board generates the sound. Who knows. All if it might be on your pcb and not the monitor at all. I would probably start checking voltages on the ps as well as checking the game board itself and make sure everything is getting good contact. Other than what I said I'm really not sure because both happening at the same time kinda confuses me and has me leaning towards the game pcb itself or the power going to it.
 
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That's very odd. Maybe check solder joints for the ground coming from the tube? as for the sound have you tried cleaning the legs of the eproms and putting them back in? I haven't seen one of these boards before so I don't know what part of the board generates the sound. Who knows. All if it might be on your pcb and not the monitor at all. I would probably start checking voltages on the ps as well as checking the game board itself and make sure everything is getting good contact. Other than what I said I'm really not sure because both happening at the same time kinda confuses me and has me leaning towards the game pcb itself or the power going to it.

Found the keys so I will look at this tomorrow AM and report back. I will start with the usual stuff - checking all connectors (its a cage with several boards), reseat roms, check voltages etc.

Thanks for the help so far!
 
Sounds good. While your messing with the eproms you might as well clean the legs with a pencil eraser to make them nice and clean.
 
If it has masked roms I wouldnt mess with them unless the game is not booting. Your sound problem may be one of the custom chips.
 
Alrighty. small update. I replaced most of the boards with a known good set, made sure they were well seated in the cage (it was very old and dirty) and gently checked the monitor chassis/board connections.

Now I have a mostly working game. However. The player shot sound, while its definitely there, is very faint. Its hardly audible when there's a lot of action (galaxians diving for example) but its definitely audible in quieter sections of the game. Any thoughts?

Also, the monitor flicker is more or less gone. There's a little still there from time to time but its more a kind o 'wobble' rather than a full on corruption as I was seeing prior. Could it be a simple cap kit issue? The colors and contract are very vivid.

The only board I didn't replace yet is the CPU board as the one I have has a loose heat sink. I never reattached these - what do I use? It appeared to be glued in place on the original, I guess its a special compound?
 
From your video.....it seems to be missing speech, also.

In the boardset cage.....one of the boards is called the "game board". It's the one the harness plugs into. On that board are two 40-pin chips. They are identical. These are custom chips that handle audio/input/output. These are the customs Riptor was talking about. Swap these chips locations.....and see if the issue changes (different sounds not working, or controls not working).

Edward
 
They used a glue similar to super glue to glue on the heatsinks. You can use the same or JB weld.
If you can hear the sounds faintly thats a good sign. Check the audio amp board and make sure both pots are turned up. There are also some resistors on that board that like to burn up. Ohm out all the resistors and make sure they are in tolerance. The ones I speak of usually show signs of burning so it should be obvious. I always replace these with a 1/2 watt part. You may find that one of the two channels is not working. If so, check those resistors and replace the TIP31 with a TIP31C.
 
From your video.....it seems to be missing speech, also.

In the boardset cage.....one of the boards is called the "game board". It's the one the harness plugs into. On that board are two 40-pin chips. They are identical. These are custom chips that handle audio/input/output. These are the customs Riptor was talking about. Swap these chips locations.....and see if the issue changes (different sounds not working, or controls not working).

Edward

Actually I do have speech. Hadnt spotted that on the video!!!! Thats working just fine, now at least.
 
They used a glue similar to super glue to glue on the heatsinks. You can use the same or JB weld.
If you can hear the sounds faintly thats a good sign. Check the audio amp board and make sure both pots are turned up. There are also some resistors on that board that like to burn up. Ohm out all the resistors and make sure they are in tolerance. The ones I speak of usually show signs of burning so it should be obvious. I always replace these with a 1/2 watt part. You may find that one of the two channels is not working. If so, check those resistors and replace the TIP31 with a TIP31C.

Ah OK... I didnt expect SuperGlue would be good - kinda thought it may unglue with teh heat or damage the chip? I am over in the UK now so I dont think we have JB Weld but I can take a look. Super Glue will definately be OK?

Which board is the audio amp?
 
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