Monitor making cracking/sparking noises. A newbie needs help.

[Paul_in_nottingham]

Hi there, 

This is my first post so sorry if I'm asking a simple question, I have tried to check.

I have recently managed to get my hands on a Ridge Racer Upright cab.  All was well with the monitor, bright, sharp picture and no interference until I tried to 'fix' the Marquee light.

I replaced the marquee tube and fluorescent starter recently.  A couple of days later I noticed that the screen was displaying occasional 'snow flake' like interference, quite sparse; not like on a normal analog TV.
Then the monitor emitted a sparking/cracking noise and the screen went blank for a split second.  After this it seemed to work fine until emitting another crack a few minutes later.

After finding this forum, I have read about the florescent tube interfering with the monitor.
I then removed the starter from my light fitting.  To my surprise when I powered it up the tube still continued to light, however the monitor was perfectly clear.  I then decided to disconnect the tube anyway just in-case.  After powering up again I found the interference was back and so was the occasional cracking.

The monitor is still making the cracking noises and showing some occasional interference.  Although, since disconnecting the light, the cracking seems to be reduced.  When working normally, apart from the small amount of interference, the picture is fantastic. 

I'm pretty sure it's a 25" Hanamatrix Polo fitted.

My question I guess is have I damaged my monitor?  Do you think the light may have played a part in causing this or is that just coincidence?  Is the monitor simply starting to show signs of being 14 years old?  Any suggestions of further thinks to confirm fault and hopefully remedy it would be greatfully appreciated.

Thanks in advance.

[SirPeale]

The interference usually caused by florescent fixtures is magnetic, so I doubt this is your problem.

I'd open the cabinet back, turn off your lights, and watch the chassis.  If you see any sparking, note where.

[Paul_in_nottingham]

Thanks for a speedy reply.  I'll give this a try.

[Ken Layton]

It's possible for the monitor main circuit board to have developed some bad solder joints on the foil side of the board over the years. It's also possible that the "flyback" transformer (which generates the 24,000 volts to operate the picture tube) is developing some pinholes or cracks in it's casing which means it must be replaced.

[Paul_in_nottingham]

Well, things have worsened.   

Housemate and I were playing on it the other evening when, after a couple more cracks and pops, the picture shrank to just a inch high horzontal line across the centre of the screen.  Also accompanied by an electrical burning smell.

I've searched these forums best I can.  Would I be right in thinking that installing a CAP kit and new flyback might solve the problem?

I have some basic experiance with electronics as I used to be a bit of a hobbyist and did a GCSE also, so I'm not too phased by the idea of changing Capacitors; I'll be careful and heed all the warnings.. promise.

Am I on the right lines of thinking?

[Ken Layton]

Yes, sounds good.

[SirPeale]

Yes, sounds good.

What about the vertical IC?

[grantspain]

if you get stuck you could send it for repair to hantarex u.k,they are based at sydenham hill,south london-you can buy the caps from maplins,the flyback transformer and vertical deflection i/c(frame chip) from brent electronic/suzo/hantarex

[Paul_in_nottingham]

Thanks for all the advice thus far!

Looked at the Hantarex site about a repair, however postage to London and back + repair fee seems more than its probably worth.  I also E-mailed them about the cost of a new monitor, as yet no reply.   

Do you know the values of the Caps to get from Maplins? How do I identify the ones that are likely to need replacing?  As I understand it probably won't be all of them on the board?

I'll contact said companies about flyback and vertical IC.

Thanks all, I'll be sure to keep you posted

[grantspain]

the caps i would replace are the following:
POWER SUPPLY CIRCUIT
c114 22uf 50v
c111 220uf 25v
c112 22uf 25v
c121 100uf 200v
c123 10uf 100v
c125 470uf 35v
c129 220uf 25v
FRAME CIRCUIT
c137 220uf 35v
c139 1000uf 35v
c142 47uf 25v
c144 1000uf 35v
OTHERS
c14 4.7uf 250v
c177 47uf 250v
All these capacitors are electrolitic and rated at 105 degree's
the frame/vertical i.c is a TDA1675 at position i.c103,you will also need heat sink compound(heat conductive gease) if you change this-make sure you check resistor r167(2.7ohms anti flame) and L105 if used on your board both these resistors are protection for the 27volts frame i.c power
when you order the flyback transformer make sure you state the full model number and size of the tube e.g hantarex polo 25
hantarex have been closed for christmas,the price of a replacement chassis is around 150 pounds,the cost for all the above parts will be around 40 pounds and alot of time and good soldering skills

[meltman]

If something did burn in the chassis, chances are you can visualy inspect and find the source of the fire.

[Paul_in_nottingham]

Thanks for the Help!  You guys certainly know your stuff.

Right, had a look at the back and certain i've identified the problem part.

The rear of the pcb attached to the tube shows signs of arching and round 1 component, the solder has melted, crossed tracks and even in some places lifted the copper track clean off the board.  Here are some pics.  Check out the bottom right.

http://farm1.static.flickr.com/137/345647295_b32cdab7e1.jpg

http://farm1.static.flickr.com/163/345647329_5a9c796a9a.jpg

http://farm1.static.flickr.com/127/345647311_7df181fe07.jpg

Also, there seems to be additional damage around a resistor on the back of the board....

http://farm1.static.flickr.com/152/345647331_ea00631461.jpg

The model is definatly a Hantarex 25" - The only other number on the lable is IMQ N.V3373

The board on the rear of the tube has the following codes on it:  VV06 and 50148384

http://farm1.static.flickr.com/134/345647325_63949407f2.jpg


Am I right in thinking a flyback kit will include this board that attaches to the back of the tube?

Will I need to do a Cap kit on the main board as well?

Thanks again for the help.

[grantspain]

that is the neck card and they are common burn up's you can see around the colour drive transistors although poorly repaired this will not cause your fault,if there were bad conections on the drive transistors then your colours would come and go or fire full on-this board would not come part of any kit,you would have to buy a replacement
you should check for bad solder joints on the main chassis first