Supergun Sync Issues

OldFoo · Post by **OldFoo** » Mon Jul 24, 2006 1:02 pm

Hi All,

Well I finally finished my supergun. It's not the smallest, or the prettyist, but it does the job & my TV has a much better image than my fooked monitor.

The issue I have is that when testing a load of PCB's I found 2 or 3 that had sync problems. Not so much as a rolling picture, but almost like stripes of mess.

I tried these boards on my cab, and no problems.

I'm assuming these boards must be outputting a slightly different sync frequency compared to other boards, which the monitor is happy with, but the SCART TV thinks Fook Off!

Would putting a variable resistor in the sync line be of use, or would I need a circuit to do this (if so any ideas???)

Cheers all,

John

OldFoo · Post by **OldFoo** » Mon Jul 24, 2006 5:27 pm

certain games will only work with monitors that can sync between 50 - 60hz, certain Schmup games by Seibu Kaihatsu sync at ( i think) 54khz,this could be why your having problems

what boards are they anyways ?

OldFoo · Post by **OldFoo** » Mon Jul 24, 2006 10:09 pm

Like megalo said, check your tv's manual for syncspan if it seems to be OK, check your +5V line. Are you using the same PSU in your cab?

I had sync problems with my donpachi pcb but it turned out to be voltage issues. It suddenly decided to simply demand more juice one day, almost 5,55 instead of 5,00.

OldFoo · Post by **OldFoo** » Tue Jul 25, 2006 10:44 pm

Cheers for that.

Can't remember games. They're pretty shitty which is why I haven't bothered before.

Will try the 5V lines, but the cab & SG psus are the same & set to the same voltages.

OldFoo · Post by **OldFoo** » Wed Jul 26, 2006 12:05 am

Always check voltage directly on the pcb itself. It can change quite a bit through the loom and connections.

Even if you have two identical psu's set to the same voltage other factors may intrude and change the "end voltage". The best place to check is probably directly in some IC on the board, atleast that's how I do it.

I don't say that this is your problem, just that it MIGHT be. Nice voltages is always a good thing.

OldFoo · Post by **OldFoo** » Thu Jul 27, 2006 10:05 am

The missus is working tonight, so I can test the system without complaints / moaning etc...

Will dig out the old multimeter & have a check tonight, as long as I can keep the hardcore in the cupboard!