Hantarex Polo 25" Arcade Monitor - problem...

[scumball]

First post...and as usual a problem to sort out.

I have a Hantarex Polo 25" monitor in a Jamma cab.

I have lost my black! It has become dark blue. All colours and white seem fine, but no black. I've tried playing with the contrast, brightness etc on the remote board but no change. My Xbox boot up screen and MameDox front end look naaasty.   It is the same when connected directly to a Jamma PCB and also via a PC with ArcadeOS.

If the H Amp is not stretched out completely (resulting in a distorted image) then I get a light blue interference/multiple ghosting over the top of the dark blue (where there should be black).

Anyone know anything about arcade monitors or the Hantarex Polo in general?

Failing that, does anyone know anyone/where in London that may be able to do a site visit to diagnose/repair. I really don't want to discharge this monster to remove it, either for repair or replacement....

[grantspain]

i think you have a set up problem,can you post a picture of the problem-there are loads of people in london that can help,also you have hantarex down at sydenham hill

[scumball]

I just spoke to a guy at Hantarex about my problem, and he said it's probably the chassis.  He said I should send it in for repair.  I mentioned high voltages and needing to discharge it first and he said that wasn't necessary as long as it was not plugged in.  I'm a bit wary about doing this as everywhere I've read has said you should discharge a CRT before touching anything...I have no means of doing this and don't really want to have to.  Anyone removed a Hantarex chassis safely?  Care to talk me through it?

Secondly he stated a new chassis is

[grantspain]

firstly is this a polo1 or 2?,secondly i don't think this chassis is faulty-you have further colour adjustment pots on the neck card for your foreground and backgrounds,the distorted width is down to the pincushion adjustment which can be found on another pcb that stands upright on the chassis if polo 1 or on the remote board if polo2(i'm guessing your picture bows in or out)-i honestly think this chassis just needs setting up correctly-if you feel the need to remove the chassis then i will talk you through it-the hantarex polo have a discharge circuit for ht so there is no chance of electric shock if you switch it off first,but first get a picture of your screen onto this thread so i can see exactly whats going on,another question did this monitor just go like this or did you buy it like this?

[scumball]

It's a Polo 1.

It arrived to me perfectly.  One day I switched on and it was like this.

I have made further in-roads and have got some sort of black back by crushing the contrast using the screen pot on the right hand side of the chassis (not the contrast or brightness on the remote board).  With the contrast right down on the remote board, the brightness about half way up (any more and the blue comes back) there is black.  The picture doesn't look as good as it used to when I first got the cab about two weeks ago, but it's a lot better than yesterday.

I adjusted the RGB pots and got rid of the light blue interference.  I have not touched the pincushion pots before (mind you I hadn't touched the screen / focus or RGB pots until today) so I'm not sure how that got out of whack.  If they're are the ones on the small board in the middle of the chassis I take it they should be adjusted without power.  If so, how do I know if it's getting better or worse?

I have attached a picture, as you can see quite a lot of bowing at the edges, and it's very dark all over (but better than blue)...

[grantspain]

i think your problem is some dry joints(bad solder joints),i have posted here before a good setup proceedure for monitors-basically you need to turn all your pots down(on the remote brightness and contrast,on the neck card all the drive and background pots and the screen volts on the lopti),then you start by turning the screen volts up untill you just make out a picture(use a mirror),then turn up your background colour to half way,then your contrast a little,then the brightness a little then your foreground(gains) colours untill you see depth in the colour,then its a case of fine tuning using all the pots-as for the problem with the pincushion you can adjust those pots on that upright board with it switched on-but first you must check for the bad solder joints,its very easy if you tap the chassis gently(tap the metal frame) and your picture jumps or is affected then you have a bad solder joint,these are usually very easy to see as you will notice cracks around componants-if i can help anymore then let me know,also i know a guy in the medway towns that maybe able to help but obviously this would cost

[scumball]

I think it's fixed!!

I adjusted as you said using my Fight Club THX DVD colour bars etc.. and it looks great.

God knows how it got so out of whack without touching it....

Thank you, thank you, thank you...you've saved my sanity and money.