Build Your Own Arcade Controls Forum

Main => Monitor/Video Forum => Topic started by: JoshuaMiller on October 05, 2006, 12:06:31 am

Title: Monitor Died !
Post by: JoshuaMiller on October 05, 2006, 12:06:31 am

Hey guys-

Still haven't resolved the ArcadeVGA problem from my other thread, but am having a new one. . .

I got a pc picture on my machine, but it was really messed up.  I tried to adjust the picture, but could not get anything decent (black background with distorted green icons in windows).  I assume that my video card is not compatable with Jpac.  That's ok, because I want to get the ArcadeVGA working anyway.

The problem is, after it was on a few minutes, the monitor DIED altogether.  It is getting power, but the end of the cathode tube is not glowing, and it is making a high-pitched chirping noise (sounds like a cricket).

Do I need to replace my caps?  I want to make sure that it is nessicary before I undergo such a huge procedure.

Thanks guys, you're always a great help.

--Joshua--

Title: Re: Monitor Died !
Post by: grantspain on October 05, 2006, 08:13:11 am

more than likely its your h.o.t blown because it sounds like you were feeding the monitor too high a frequency

Title: Re: Monitor Died !
Post by: JoshuaMiller on October 05, 2006, 01:22:01 pm

Thanks.  Does anyone know where I can find the hot on a hitachi monitor?

I'm at work now, but can get photos/exact model # tonight.

thanks-

--Joshua--

Title: Re: Monitor Died !
Post by: JoshuaMiller on October 05, 2006, 10:20:53 pm

Question-

I was routing through a Jpac board when this happened, the Jpac is not supposed to send any signal to the monitor if it is out of sync, so how did it get too high a frequency?

Title: Re: Monitor Died !
Post by: grantspain on October 06, 2006, 03:35:57 am

i'm no mame expert but i assume a jpac feeds a 15khz monitor with a converted 31khz signal therefore if the fault happened whilst you were playing with the jpac all i can assume is some sort of frequency spike occurred,for a monitor to just do this fault on its own is unlikely
i do know if you feed a 15k with 31 k the horizontal output transistor cannot cope with the signal and blows,its a common problem on this forum
always you have to look at a common cause of the problem;playing with jpac and the monitor shuts down,cause is either faulty jpac or signal problem

Title: Re: Monitor Died !
Post by: JoshuaMiller on October 06, 2006, 12:43:48 pm

Thanks, grantspain-

If the monitor shuts down because of a bad signal, would it start up again with the same symptoms that I originally encountered, or not start up again at all?  Also, there is no orange glow at the back end of the tube, even when the monitor was on and getting power, so does that mean it's a problem with the monitor and not a signal problem?

Also, when researching what you said about blowing a "hot", I came across some postings about "x-ray protection mode".  What does this look like?  I was getting green details on a black background when windows was displayed on the machine. . .

Thanks for all your help-

--Joshua--

Title: Re: Monitor Died !
Post by: grantspain on October 06, 2006, 12:49:42 pm

yeah what i was trying to say if you accidentally give your monitor the wrong frequency for long enough it blows the h.o.t
usually the h.o.t will be held to the heat shield inline with flyback to the yoke circuit(its a big transistor),i think you have more than one fault here btw(one on the monitor one on the jpac/avga)

Title: Re: Monitor Died !
Post by: grantspain on October 06, 2006, 01:00:03 pm

another thing what make and model monitor have you got?

Title: Re: Monitor Died !
Post by: JoshuaMiller on October 06, 2006, 01:36:45 pm

*sigh* I guess there's no easy way out of this one!  The monitor is Hitachi, in a Japanese Neo 29 cab.  I'll get photos and model# tonight.

Thanks for all your help, guess I need to start looking for a cap kit. . .

--Joshua--

Title: Re: Monitor Died !
Post by: Lutus on October 06, 2006, 01:59:30 pm

Cap kit and HOT for sure.

Title: Re: Monitor Died !
Post by: grantspain on October 06, 2006, 03:31:30 pm

unlikely to be anything to do with caps unless there was some extreme surge through part of the circuit,cap replacements should only be necessary on monitors of more than 5 years or when a chassis is badly designed e.g when they stick a cap right next to some sort of high heat source

Title: Re: Monitor Died !
Post by: JoshuaMiller on October 07, 2006, 12:03:31 am

So I only need to replace the hot then?

Is this in a cap kit?  If not, where can I get one?  Will Radio Shack have them, or do I need to order from Bob Roberts?

I assume that I still need to discharge the monitor to replace the hot, if so, shouldn't I replace the caps anyway while it's discharged just in case?

Also, I have found several tutorials on cap replacement, but nothing on replacing a hot, does anyone have a link?

BTW- The model is Hitachi GMK-29FSN.  It is more than 5 years old.

thanks-

--Joshua--

Title: Re: Monitor Died !
Post by: Lutus on October 08, 2006, 02:09:44 pm

Grantspain, I didn't even look at how old the monitor was when I said to replace the caps.  I was just trying to convey that on the older models you may as well do a cap kit if you are doing anything else.  But you are right, a HOT is what is truly necessary now.

A HOT doesn't come in a cap kit.  Order it from Bob Roberts.  You will need to discharge the monitor.

Title: Re: Monitor Died !
Post by: grantspain on October 08, 2006, 04:12:09 pm

a cap kit is sensible on anything over 5 years,agreed
i need a schematic to id your h.o.t or some really good photo's-i have never seen this monitor before

Title: Re: Monitor Died !
Post by: JoshuaMiller on October 08, 2006, 04:48:29 pm

Thanks for all your help guys.

I'm ordering a HOT and capkit from B.R., I figure I'll do all I can just to be safe since I have to discharge anyway. 

I'll scan the schematics tomorrow at work and post them, they are in Japanese, though. . .

Thanks again-

--Joshua--

Title: Re: Monitor Died !
Post by: JoshuaMiller on October 10, 2006, 03:17:21 pm

Schematics-

Title: Re: Monitor Died !
Post by: JoshuaMiller on October 10, 2006, 03:18:56 pm

Another one-

Title: Re: Monitor Died !
Post by: JoshuaMiller on October 10, 2006, 03:21:48 pm

Also, I'm having a lot of trouble finding info on replacing a HOT, or even what a HOT is! (horizontal output transmitter?)  Can anyone enlighten me on the subject?

Bob Roberts does not carry anything that I need!  Checking Japanese sources, but does anyone know another US source that might have Hitachi parts?

Thanks for all your help guys-

--Joshua--

Title: Re: Monitor Died !
Post by: grantspain on October 10, 2006, 03:51:20 pm

sorry those schems are no good,maybe you can get some good photo's
the h.o.t is bloody big transistor clipped to the flyback heat shield-i am gonna look for some schems myself
i have a feeling that the tube is hitachi but the chassis is a sanwa-a photo will prove it

Title: Re: Monitor Died !
Post by: JoshuaMiller on October 16, 2006, 01:13:37 am

Finally have those photos. . .

Not a lot of room in the cab to get good, wide shots, but if you need better ones to help diagnose this thing, I'll take the boards out, since it looks like I'm going to have to discharge to fix the problem anyway.

Thanks Again!

--Joshua--

Title: Re: Monitor Died !
Post by: grantspain on October 16, 2006, 03:12:00 am

i have never seen that chassis before,it looks like a nanoa/sanwa but it ain't-i can still id the h.o.t but the whole chassis would need to be out the cab with some better pics

Title: Re: Monitor Died !
Post by: JoshuaMiller on October 16, 2006, 12:30:23 pm

Yup, that's what I thought, better pics. . .

I have a feeling that it is a Hitachi, just because the brand and model# are on the frame of the chassis (in front) and not on the tube.

Anyway, I'll discharge it and get you better pics as soon as I can.

Thanks for your help grantspain, I've come across many of your posts researching this, and you seem to be the man when it comes to monitors.