shmups.system11.org

I have had one of these scart switches in the image below for awhile hooked up to my PVM 2950Q.
My turbo grafx, genesis, snes, all hooked up via composite video to an lm1881 sync stripper. Works fine.
I recently hooked up a 32x via composite sync as a new input to the switch. However, it keeps losing sync randomly.
If I hook it up to input 5 it is fine, but all other inputs and it loses sync.
Anyone else ever had any problems like this with scart switches?

Not sure if it's the same issue as I encountered, but I had to cut a trace on the 5th input for all the inputs to work properly for me.

Yeah cutting that line didn't seem to do anything. And I verified there is no continuity there anymore. It seems to be connected to a diode and +5V. No idea why. Possibly to isolate other lines somehow from taking the +5V.
I did notice there was yet another diode below the cut trace diode, and when I jumped the diode the sync starts working. When I remove the jumper wire, it stops working again. I checked the voltage and the diode appears to be dropping the voltage from 5V to 4.7V. Which I guess is enough to make the sync stripper stop working. I wonder if they are expecting voltage there higher than 5V.

For any future people who might have been brought here by a search for "Brandbridge" and "Scart Switch" and "composite sync" and "not working". Well just remove the two diodes from the PCB and replace them with jumper wires. They were stealing voltage needed for the lm1881 sync separator Everything seems to work now.

Interesting, glad you got it to work after some further cutting. Weird though that you had to cut in 2 places though when I only needed the one.

As I recall I had similar problem with a syncstripper, the issue was that it lost the neccisery voltage on the pin that supplies the power to the stripper so I got an external powered syncstripper and it works flawlessly even with 2 of those scart switches daisychained.

The diodes are 1N4004(for surge protection or something). D1 links selected input pin 8 with OUT pin 8, so the LM1881 didn't get enough volts. D2 links selected input pin 8 with AV5/VCR pin 8 and causes some consoles to power on, most likely intended for some SCART VCR mumbo jumbo.

Maybe a better solution is to replace D1 with a jumper wire(= no voltage drop on output) and remove D2 (= no more power to AVR5/VCR when not selected & no trace cut necessary).

BTW the screw covers goes of easy when pulling with Blu-Tack.

How do you even take this switch apart? I can pry it open with screwdrivers, but not without damaging it.
Please help other users trying to attempt opening it.

There are covered screw holes on the bottom.

Thanks, this guy reeally does not like being modded. I've had several pieces of equipment open, console, gaming, audio, video and other hardware. None were this difficult. Putting it back together however is really easy. Good design.

There are 4 covered screw holes on the bottom on each corner, I took a small drill and drilled through them
And there are three more on the bottom, look for what looks like it came from the mold. These 3 can be flipped out with a hobby knife.
So 7 hidden screws on the bottom.
The screws on the back, you can just leave them in.
I spraypainted the front to black. It looks much better now. Silver? what were they thinking, it looked* so cheap

* see what I did there

Yeah, my switch was all scratched up trying to get the damn thing disassembled for taking that picture. Definitely was a pain. Fortunately since they are on the bottom of the device, they're not really visible and the person I sold it to didn't mind.

Hello

I finally could mount my setup (was waiting Framemeinster and cables). And now, I have a doubt about the switches that maybe you could help me.

My setup is two 5 way automatic Bandridge switch and a Framemeinster. So, I have 9 inputs (need a output to link both switches).


All systems from Switch 1 work normally, but I don't get screen image from some systems from 2. Only audio.

My fist test was change some systems from 2 to 1, and it worked. So, the problem is when I pass the signal from some systems through two switches. And I said SOME once Genesis, SNES and DreamCast worked through 2 switches.

Do you think that the diode thing could help?
Thanks

This is what I ended up doing, works great!

In order to get the screw hole covers out, what I ended up doing was to hammer a nail partly through them then pull it out with the nail and move on to the next one. No scratches or damage to the plastic underneath this way.

Maybe there are different revisions of this switch? Because I have two SVB7725 daisy chained and a PAL GC with an LM1881 in the SCART head sitting at the chained switch with no issues, trace cut mod on both. Also note that there is a SVB7725 and a VSB7725. Made a thread about that, both seem to work just fine but I did not open the VSB7725 to look inside.

Just did this on a Bandbridge SVB7725, worked a treat!

Although for some strange reason the scart input 1 has a blush hue to it? Tried different cables and its only that one input that does it?!
All soldered pins internally look fine and continuity across all pins is good too, very odd. I don't need all the inputs so its not a problem just weird.