Pentranic/288-ch monitor ticking

[cgaw69]

I just purchased this cabinet and monitor and after transporting it just ticks. Before transport all was OK. Any schematics or board layout would be great.

Thank you in advance for all your help.

Craig

[Kevin Mullins]

If it only quit after moving it, the first things I would look for are bad connections and bad solder joints. (won't need schematics to do that stuff)

[cgaw69]

If it only quit after moving it, the first things I would look for are bad connections and bad solder joints. (won't need schematics to do that stuff)

I already checked solder joints etc. That is why I am here. Just out of ideas.

Thank you

Craig

[Mauzy]

Here's the schematic:

http://niemandisplays.com/nvd%20ch-288%20cga%20only.pdf

Good luck!

[cgaw69]

Thanks Mauzy I appreciate. You don't know who might have a board layout and test point voltage readings? My plans are to convert this cabinet to a MAME.

[Mauzy]

Well, let me say first that you must know what you are doing before you start poking around these monitors. There are many high voltage points on the chassis, neck board, and tube. The only reason I say this is because I don't know your skill level, not to insult or attack. Have you read the FAQs? You do know about discharging and such, correct?

That said, the ticking is more than likely the shut-down circuit protecting whats left of your monitor. As for where this is or how to fix it I have no clue. I have just seen those symptoms on several monitors and have seen the gurus around here tell people this is the problem.

As for layout and voltage readings, I don't know where on the internet to find those, but I have an identical monitor in one of my cabs. If you need any voltages I can try to get them for you. Just let me know.

I just noticed that you said after transportation it no longer works. You did check the fuses, correct? I see that you did check for bad solder joints, so I assume you would check the fuses as well, just making sure.

[cgaw69]

Well, let me say first that you must know what you are doing before you start poking around these monitors. There are many high voltage points on the chassis, neck board, and tube. The only reason I say this is because I don't know your skill level, not to insult or attack. Have you read the FAQs? You do know about discharging and such, correct?

That said, the ticking is more than likely the shut-down circuit protecting whats left of your monitor. As for where this is or how to fix it I have no clue. I have just seen those symptoms on several monitors and have seen the gurus around here tell people this is the problem.

As for layout and voltage readings, I don't know where on the internet to find those, but I have an identical monitor in one of my cabs. If you need any voltages I can try to get them for you. Just let me know.

I just noticed that you said after transportation it no longer works. You did check the fuses, correct? I see that you did check for bad solder joints, so I assume you would check the fuses as well, just making sure.

Mauzy,
I have an associates degree in electronics engineering tech. I also worked in the 2-way radio repair business until the cellphone killed that market. I am now working for the local tel-co installing and programming phone systems. That said I appreciate any help that anyone can give me. I have a high impedance probe for discharging monitors and all soldering and desoldering equipment.
 
Thanks again for all your help. Even have the high voltage gloves.

[cgaw69]

Mauzy,

Sorry, I didn't mention this before. The tube has a sticker on it saying that this monitor doesn't need a isolation transformer. But I noticed that it seems to have one installed in the cabinet.

Thanks again,
Craig

[qrz]

Mauzy,
I have an associates degree in electronics engineering tech. I also worked in the 2-way radio repair business until the cellphone killed that market. I am now working for the local tel-co installing and programming phone systems. 

active , or ever consider Amateur Radio ?? 


SMPS's tend to tick or squeal in a high load condition.
typically , the common cause is a shorted hot . check across CE ( Q401- BU2520D )
also check solder on T301 driver xformer.  a loose connection here can kill an hot - quick !
and check c456.  a value change /high esr can adversly affect the waveshape and stress the hot

   T501 provides monitor isolation.  redundent isolation shouldn't be a factor
c511 is start up cap      bad cap here will cause start issues
c512 vreg filtering           "     "      "      "     "       regulation  problems


73 de j

[Mauzy]

Well, let me say first that you must know what you are doing before you start poking around these monitors. There are many high voltage points on the chassis, neck board, and tube. The only reason I say this is because I don't know your skill level, not to insult or attack. Have you read the FAQs? You do know about discharging and such, correct?

That said, the ticking is more than likely the shut-down circuit protecting whats left of your monitor. As for where this is or how to fix it I have no clue. I have just seen those symptoms on several monitors and have seen the gurus around here tell people this is the problem.

As for layout and voltage readings, I don't know where on the internet to find those, but I have an identical monitor in one of my cabs. If you need any voltages I can try to get them for you. Just let me know.

I just noticed that you said after transportation it no longer works. You did check the fuses, correct? I see that you did check for bad solder joints, so I assume you would check the fuses as well, just making sure.

Mauzy,
I have an associates degree in electronics engineering tech. I also worked in the 2-way radio repair business until the cellphone killed that market. I am now working for the local tel-co installing and programming phone systems. That said I appreciate any help that anyone can give me. I have a high impedance probe for discharging monitors and all soldering and desoldering equipment.
 
Thanks again for all your help. Even have the high voltage gloves.

Oh. Well, gotta cover ---my bottom--- you know.    You should have said that a long time ago though. Considering this, I have no further knowledge for you. Give me about 5 years for my degree in EE to kick in and maybe I could lend a hand...

As for the iso transformer, it won't hurt anything. All of my monitors that do not require one have it for various reasons.

[Mauzy]

so...start working on this one yet? just capped mine and its doing the same. Guess Im going to go start reflowing everything again... helps to plug in the external controlboards...

[cgaw69]

so...start working on this one yet? just capped mine and its doing the same. Guess I'm going to go start reflowing everything again...

Yes, I have checked everything posted above but no luck. I am going to sit down tonight and double check the schematic to see where to look next. Let me know if you find anything. Just don't understand why after transport It stopped working.

Mauzy, Do you know where I can find a cap kit for this monitor? Also, Do you think recapping might help with my situation.

[Mauzy]

Yeah, thats weird considering it wasn't something like a fuse since they break in transit pretty often. My problem was the external adjustment boards. Now it has an awesome picture, but it squeals and squiggles just enough to notice.

[cgaw69]

Yeah, that's weird considering it wasn't something like a fuse since they break in transit pretty often. My problem was the external adjustment boards. Now it has an awesome picture, but it squeals and squiggles just enough to notice.

Mauzy,
Where did you find your cap kit? I would like to pick one up for mine and see if it helps. Also will double check the connections on the external adjustment boards.

[Mauzy]

I had to put it together on myself on Mouser. Ill post it once I've modified it to be more accurate. The project I put together has several duplicates that aren't necessary to the kit, but I ordered as extras to keep "in stock".