Amping the sync signal?

[MNKyDeth]

Ok, so I sold one of my friends that is local one of my repaired Duo's. He uses a BVM and the system works great plugged straight into it. Composite and RGB work without issue.

This system is a Duo-RX and it has the tg16pcemods RGB amp in it.

He bought a Euro scart splitter and when hooking up the console through the splitter he loses the sync signal. The consoles screen shows up on the BVM but it is sliding around on the screen as he says.

So... do I just need to amp the sync signal? If so I know the tg16pcemod AMP's use two chips. One chip amps green and blue the other chip amps red. Could I use the chip that is amping red to also amp the component video for sync or Sync from pin 44?

If there is no "good" solutions to this I will just have to tell him to plug it straight in. But I want see if there is a solution first. Thanks for any input.

[mickcris]

I think he maybe needs to get a switch not a splitter. those arent upposed to be used like a switch if that's what he's trying to do. What is he doing with the splitter exactly?

He shouldn't need to split the signal as the bvm passes rgb through it. Can just hook whatever up to the bvm output.

[MNKyDeth]

Ahh yes, it is a switch, I just said splitter not thinking.

And an update from him this morning actually. He said he was playing with the vertical hold last night and the screen just scrolls left and right now.

He has several consoles he is hooking up the BVM and is using the switch to change to different consoles.

Some pics of how it is hooked up.

https://postimg.cc/gallery/236vbttro/

[crazydean]

Not getting anything with that link. It just takes me to postimg.org

I'm wondering if the cable is too long. Analog signals don't do well on long trips. It could also be a poor quality switch.

[Fidde_se]

The sync is known to be low in PCE.

And every connector you add into the equation lowers it a bit.
Connector Attenuation....
https://en.wikipedia.org/wiki/Insertion_loss

Yeah you probably need the Sync amp, either build one form scratch.
Lower right: http://www.gamesx.com/grafx/pce_rgb.jpg


Or you could probably use the unused channel on the circuit you already were into,
some good ol' mod needed there.

[SignOfZeta]

Or just not use a SCART switcher. Most of them are super bad.

[thesteve]

is he using composite video as sync or just sync?
the SCART standard is composite video, but some mod the system to just do sync

[ClodBusted]

Or just not use a SCART switcher. Most of them are super bad.

So true. I've tried both cheap as well as expensive ones. They all introduce visible interference, some more obvious than other.

[L-Digital]

It's Almost certainly the switch. I have tried them all and most are junk. Post a pic of the switch please

The best switches you can fairly easily get are bandridge. There is also a good Hama out there but also some poor models so be careful

[MNKyDeth]

The scart switch he is using looks exactly like this one from this thread.
https://www.pcengine-fx.com/forums/index.php?topic=20679.msg450985#msg450985

Correct link to pictures of how it is hooked up.
https://postimg.cc/gallery/236vbttro/

I have the console getting sync from the composite video. I did not hook directly to pin 44 on the Hu6260.
The Euro scart cable I supplied him was from retrogamingcables.uk
He is using a scart to BNC cable from the switch. He says the console displays just fine using the original composite video cable and the RGB Euro Scart cable I supplied to him. The issue is only when he adds in the switch.

[L-Digital]

It's almost certainly the switch. If he goes direct from PCE to bnc adaptor without the switch does the problem persist?

There is only 1 good version of that type of switch and it is Hama

I have owned and tested it to be rock solid with PCE and other weak sync types

It has white writing that says Hama and is made of plastic, not metal. They do a cheaper version of the same switch with a lower profile and no white writing which is junk

[ClodBusted]

So I guess this switch happens to be the one you're speaking of?

https://de.hama.com/00042945/hama-scart-umschaltpult-3-fach-schwarz

I also saw another one with a slightly different case design:
http://www.expert-technomarkt.de/Empfaenger-und-Verstaerker/Hama-Scart-Switching-Console-100S-Schwarz-25-99,99.html?campaign=Commerce-Connector/Audio,Video-und-TV/HiFi/Empfaenger-und-Verstaerker/Scart-Switching-Console-%22100S%22

If one of these is the good one you mentioned, I'll give it a try.

[L-Digital]

First link is the one I meant yes


The other link didn't work

[thesteve]

you could add an LM1881 to the scart to BNC cable
it will give you a strong sync from composite

[MNKyDeth]

Ok, looks like he is going to try getting his hands on one of the Hama scart switchers. If that doesn't work then I will see about adding in a LM1881 to the cable.

I guess I should also mention that he has the exact same issue with his RGB modded Intellivision with this switch. He didn't tell me this right away so I assumed it could have possibly been the sync signal in the Duo. Now I know it's the scart switch as it fails with any of his consoles.

[Duxcub]

I have the console getting sync from the composite video. I did not hook directly to pin 44 on the Hu6260.

My Sony PVM will only accept a c-sync signal for sync. It looks scrambled like in your pics if it is trying to use the composite video signal for sync.

Edit: the mods i have done for my personal setup all use an LM1881 inside the console, and output the resulting c-sync signal on the composite video pin of the SCART cable.  However, this method means that i can't use the consoles on a regular tv through composite. 

So putting an LM1881 in the cable from the switch to the PVM is probably the best solution, imo.  That way he can still use composite video on all his consoles, but that single cable will strip the sync from the composite signal of anything connected to his PVM.

[mickcris]

If you still have that sync strip cable, it has an lm1881 in it. You could try it on his setup to see if it helps.

[MNKyDeth]

Mickris I do have it. I may try the cable at some point but... Because of this thread he is going to buy a Hama scart switch to see if it makes any difference from the one he has.

Duxcub, his setup works just fine when hooked straight into the BVM without the switch. His Intellivision also works just fine. It's only when it goes through the switch is there an issue.


Just for clarification.

The RGB modded Intellivision and Duo-RX both use the sync signal from the composite video. Both work fine when hooked directly into the BVM.
Both display a messed up image when using the switch.

[Keith Courage]

Any updates on this? Did the new switch fix the problem? I've come across someone else with the same issue. Regardless of using c-sync or composite video for sync the same thing happens but only when his pc engine is hooked up to his switch. His other systems work just fine through it.

[MNKyDeth]

I don't think he ever found an official Hama switch. So he is still swapping cables for a direct connection to the bvm. I have not tried the cable I have from Mickcris yet that has the LM 1881 in it. So I do not know if that would have solved the problem or not.

I am actually meeting up with him on the 14th of this month. I will see if he has searched further for an official Hama and most likely I can take the sync stripper cable I have from Mickcris for testing. At that point I can let you know.