Polo Hantarex 25" no red

[Bunnyuk]

Hi guys,

I recently purchased a gaming machine and the Monitor is as above.

I have no real red in street fighter for ken or the health bars, they just appear black.

If I adjust the red cut off on the neck board the main screen will go red tintish instead of black but the life bars and ken are still black.
The red gain doesn't appear to do anything either when adjusted.  I've had a new Lopt fitted and checked all simple cabling from the red cable output on the monitor to the jamma loom.
I believe the engineer also replaced this third transistor (capacitor) in the pic.

Where do I go from here? Please help.

[jtslade]

Do you have another Jamma board to test with? Or the TPG from Crafty?


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[jtslade]

Have you checked all voltages


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[baritonomarchetto]

Run your monitor WITHOUT a video signal: what color your raster is? If it's white, the color problem is in the PCB,  if it's cyan the prob is in the monitor and it's highly probable that replacing the red video output transistor will solve

[Bunnyuk]

Hi JtSlade,

Unfortunately I don't have another game board to test.

What are the correct voltages and am I testing everything on the chassis or just the neck board?

Cheers

[Bunnyuk]

When I checked VDC I got two of the three transistors at 60 ish

The third located on the left on the pic was 34?

[grantspain]

out of interest where did you get the monitor chassis

normally a colour missing is something physically broken on the neck card
it could be drive transistor or the lm1203 ic

also do what a previous post mentioned,disconnect the video signal and then use the screen volts to obtain a raster-then adjust each cut off pot to see if you get that individual colour saturate the screen

[Bunnyuk]

From VideoTronics in the UK.

How do I  'use the screen volts to obtain a raster'?

Also where do I find the transistors / resistors and IC chip?

Thanks

[Bunnyuk]

I'm going to replace all 3 resistors and the three drive transistors on the neck board.
Can anyone help with exactly what I need to buy from say maplin or Rs components.

The Resistor looks like it says 6k8 and on hantarex schematics for the neck board it says 1/4w (watt I presume)

Not sure on the transistors?

Thanks

[grantspain]

does it have a small circular holo microdot on the heatshield,if so this is a chassis i did for mo last week and the grey load resistor was snapped from the neck card-probably find its been whacked in shipping and done it again

[Bunnyuk]

 Hi GrantSpain,

That's the one, did you test the red?

The pic on the monitor was superb and I was told a new lopt had been fitted.

Did you fit a new ic1 lm1203 as also looks new?

Just no red :-(

Could it be the colour drive transistors if not resistors?

[grantspain]

unless that has been damaged in shipping its not a chassis fault,it was working perfectly when it left me



your next step is to locate the red cut off pot on the neck card and adjust it to see if the screen saturates with red

[Bunnyuk]

It does saturate with red.

I've noticed the ribbon cable looks iffy on the soldering?

[grantspain]

nowt wrong with that,ok so your red signal is most likely missing then

now go to the video signal plug and swap the blue and red over-see what happens

[Bunnyuk]

Hello guys,

With the amazing help of GrantSpain I have a top working monitor again.

Infact the problem was related to the Graphics Card.

Thanks for all the posts and help on this.
Cheers