Nanao Chassis Black Level Pot adjust how ?

[s8n187]

hi team , i want to adjust the Black Level Pot on my Nanao Chassis 15k/24k (unknown chassis model to me) because when hooking up my PS2 to the New Astro City via Ultimarc PS2 console adapter to my JPAC the image is too dark , ive tried upping the screen volts on the flyback transformer it helps a bit but not enough.


edit:  i found out its a Nanao Chassis 15k/24k MS9-29A-T-SU

some pics









any tips are welcome

s8n

[Kevin Mullins]

Is there not a brightness or contrast pot amongst all of those ?

[ken_cinder]

Is there not a brightness or contrast pot amongst all of those ?

Similar chassis to both my Nanao's, yes there is a contrast cutoff pot on the chassis itself and the remote board has contrast AND brightness pots.

Picture looks fine to me though, you're probably used to an over-saturated and too bright picture on your TV. Turning the contrast up a bit may help, too high and you'll get color bleed though.

[Kevin Mullins]

I'm also going to assume the SCREEN voltage may need to be turned back down before adjusting the brightness and contrast otherwise they may be tooooo sensitive and cause some "wash-out" and bleeding.

[ken_cinder]

Apparently the Ultimarc adapter doesn't play nice with the PS2, but works fine with the PS1 (It's original intended use) from what I've been able to find.

Bypass the adapter for RGB, but use it for sync. Put some 220uF (Or the closest you have) 5v-10v capacitors on the RGB lines.
If your black level appears washy, throw some 50-75ohm resistors in before the caps.

[s8n187]

hi team , i have made a slight error in reading a reply from Arcade Otaku forums and no real 'black potentiometer' exists sorry about that.  But ive been given a link to shmups forum where people are having the same dark picture using Ultimarcs PS2 Console Adapter and it has a possible fix on that same page , im going to build a prototype soon and see if it works.

but even though ive learnt a thing or 2 from your replies Kevin Mullins and IJTF_Cinder thanx for that

sorry for the wild goose chase on the 'black potentiometer' bs but even tho i got some great tips for building a prototype fix and Flyback Transformer bleeding.

thanx for everything team

s8n

[Kevin Mullins]

But ive been given a link to shmups forum where people are having the same dark picture using Ultimarcs PS2 Console Adapter and it has a possible fix on that same page , im going to build a prototype soon and see if it works.

Signal amplifier maybe ?

[s8n187]

actually JPAC which the PS2 Console Adapter connects to has a built in Video Amp , but whats suggested on shmup forums is to bypass the RGB signal and route it straight to the JAMMA connector.

btw thanx IJTF_Cinder for the 75ohm resistor tip i will be doing that along with 220uf caps.

s8n