Pcb repair where to start

[FastZEdy]

I have a life force pcb by konomi. I reached out to a few common pcb repair contacts and they won't take it.

I may have to fix myself.

Overall plays great but has graphic artifact's I want to have the board repaired to address these

Picture above

RAM issue?View attachment IMG_2544.jpeg

 

[WadeLanham]

First step I take with issues like that is carefully remove and replace all socketed chips and inspect them to see if the legs need cleaned. Carefully clean the legs with very fine sandpaper if needed. A decent percentage of the time this actually fixes graphics issues. Failing that, keep looking for someone who is good with repair.

Good board guys will sometimes take a crack at a pcb they don't know well. Did you check with Ray Hepburn, he has done a good job for me so far. I have his handle here somewhere, PM me if he isn't someone you've talked to yet.

 

[VectorCollector]

Surprisingly, if you type "konami life force pcb" in Google then you will find many Lifeforce/Salamander repair logs.
Some hints to the repair (RAM/ROM or TTL) or a possible repair person can be found.

They also hint that the schematics are online.

Konami Lifeforce (GX400) Schematics?

I found schematics for the GX587 (upper) board but can't find them for the GX400 lower board. Anyone know of a source for the full schematics or at least the GX400 PCB. Thanks, David

forums.arcade-museum.com

 

[mecha]

there's some custom chips on them that apparently die. when that happens I think hope is lost. they do something with graphics I believe.

 

[ArcadeTechGW]

If they can be removed, (those custom chips) you can try the Hot POKEY trick.

Look up the thread on heating POKEYs. My theory (unsubstantiated) is that the heating either:
1. Eliminates an internal short caused by a tin whisker or
2. Reconnects a pad by allowing the solder to melt back into place

The same phenomenon may be present in these customs. If I had a decent microscope and a known bad one, or an SEM preferably, I could check.

I don't have access to either, so I live with the theory.

 

[callanbrown]

If they can be removed, (those custom chips) you can try the Hot POKEY trick.

Look up the thread on heating POKEYs. My theory (unsubstantiated) is that the heating either:
1. Eliminates an internal short caused by a tin whisker or
2. Reconnects a pad by allowing the solder to melt back into place

The same phenomenon may be present in these customs. If I had a decent microscope and a known bad one, or an SEM preferably, I could check.

I don't have access to either, so I live with the theory.

Way more likely to fry a good chip than fix a broken one. You better be damn sure the custom is the problem before you bake em.

 

[ArcadeTechGW]

Way more likely to fry a good chip than fix a broken one. You better be damn sure the custom is the problem before you bake em.

Good advice, but again, if the Custom is known bad, and it isn't the usual leg corrodes off issue (which can be fixed), there would be no harm in trying.

The fundamental principle is the same. The physics is the same.

 

[FastZEdy]

Thx guys

 

[tendril]

Not to contradict anyone above, but if you aren't sure what you're doing, don't start pulling random chips or taking a heat gun to things Analyse the problem more first, and if you need help then post more pictures also.

Firstly the game has a pretty good self test, does it give any errors on boot up? If no, then you can be reasonably sure that ROM, VRAM1, VRAM2, OBJ RAM, SCROLL RAM, COLOR RAM, etc is good.

In the one picture above I can see there are lines over the boss. But I can't tell if the lines are related to the boss (do they move around with it?), or if the problem is really the text overlay layer on top.

Where are the lines if the boss on the left side of the screen? Are there lines at other points in the game?

Figuring out if the lines are tied to sprites (the boss) or tiles (the text layer) should guide what chips to look at it.

 

[FastZEdy]

Thx will take a video. No errors on boot

 

[FastZEdy]

Video

 

[tstone]

Start by shaving your head.

It'll save you the effort of pulling your hair out later.

 

[WadeLanham]

That is a minor graphic artifact IMO that might be resolved by reseating the chips. But as someone else said if you aren't comfortable with that you might want to have someone with some experience give it a shot. Good luck!