Frequency issue - Guardiands / Denjin Makai 2

[Yamazaki]

Having the following issue with my korean Guardians pcb:

When I want to use it in my Blast City or on my Trinitron tv I get a garbled picture.
When on my PVM I need to drop the horizontal frequency to at least 90 in order to get a stable picture.

Is there any solution to this on my Blast City?
I don’t want to medle with the monitor pcb on the back side (which is a pain in the ****) everytime.


thanks in advance!

[nem]

I have the same issue. The horizontal sync is way off.

[copados33]

Your korean PCB might be a bootleg because I have the World/US pcb which is the same as the supposedly korean one and I never had that problem with any display, be it a PVM, TV with superguns and various arcade monitors, does your pcb look like this one?

[Yamazaki]

this is mine.


bought from ThomasM here on the board.

2018-05-24_170101.jpg

[copados33]

Well both of these appear to be the same with only a few masks missing on yours, but something "inside" is obviously different, I'm clueless since this not the first time I have read people complaining about sync issues with this game.

A viable solution would be to build a jamma adapter then adding some adjustable resistors on the sync lines, that's what arcade ops used to do back in the day when dealing with weird sync values on some bootleg pcbs.

[Layer]

In fact, Gfx data is stored in higher capacity masks, that is the reason there are less masks. I own the 2nd board model too.
I am wondering if these masks with "U..." stamps were made officially or done by korean bootleggers.

[caius]

Try to use on SYNC output a 5K Ohm potentiometer set as voltage divider.

[Yamazaki]

@caius:

Cool! Where on the PCB would I need to place that potentiometer to be exact?

since I guess there is no "SYNC Output" printed on the pcb


Sorry for being a noob

[nem]

Video sync is on the jamma edge, 13th pin (P) on the solder side. You wire the outside legs of the pot to video sync and ground, wiper to output.

EDIT: wrong pin!

[Yamazaki]

Thanks a lot!

[Yamazaki]

tried that and installed a pot properly like advised.

it helps changing the frequency but alas it still has the same issue on my Blast and on my PVM

[ChillingGod]

I have the same problem on my Nanao MS291 Monitor. There isn't a fix yet, right?!

[ChillingGod]

Having the following issue with my korean Guardians pcb:

When I want to use it in my Blast City or on my Trinitron tv I get a garbled picture.
When on my PVM I need to drop the horizontal frequency to at least 90 in order to get a stable picture.

Is there any solution to this on my Blast City?
I don’t want to medle with the monitor pcb on the back side (which is a pain in the ****) everytime.


thanks in advance!

I have a solution: Adjust the FH0 (Horizontal Sync Check) in the Factory Adjustment Mode of the OSD. To enter the Factory Mode press als three Buttons for 3 seconds. You get a stable picture at a value of 11 and below.