Help on this CCTV monitor (Ken Layton)

[Thenasty]

I'm trying to help out a School with this Monitor ( http://www.spytown.com/vm1201b.html?productid=vm1201b&channelid=NEXTA )
New on is about $150-$180. The problem with it (2 of them) are the video are not now FULl SCREEN.
The Top and Bottom of the screen are now black. I look at the horizontal/vertical pots and it did not fix it.
I made sure that the INPUT signal is ok from the Camera by Hooking up another Working same type of Monitor (The School have a total of 4, 2 GOOD, 2 Bad).

I am assuming it's something need changin in the PCB, but have no clue. For a pro TV repair guy, it's probably something simple.
If it's just some CAPS or Resistors that needs replacing, I can sure do it, or even to the exact component o fthe problem, I can solder it.

But, I don't know where to start. My only solution now is that go and buy and spend $300.00.

Would this be an easy fix or is it worth getting it fixed?

TIA

[Ken Layton]

If they have a SPECO monitor like that link shows, then that's a professional security monitor and is worth repairing. My local electronics parts jobber is a SPECO distributor.

First thing is something simple. Does the monitor have a switch for underscan and normal scan? If so, is it set properly?

Second thing. Is the monitor on all the time? If so, then there's a good chance it needs a capkit. Security monitors can get dried out capacitors just like an arcade game monitor would.

Sounds like these could be an easy fix. If they plan on having them left on all the time, I'd get 105 degree temerature rating electrolytic capacitors. An "ESR" type of capacitor meter will help you spot those bad capacitors.

If by chance you can't fix these monitors, MCM Electronics sells a video adapter unit that allows you to use any old computer monitor as a security monitor. Check this out:

http://www.mcmelectronics.com/product/82-10770

If you use MCM catalog promotional code (VIP pricing) C9JSTF you can get this for $39.95

[Thenasty]

Thanks for your reply Ken.

Thats the exact Monitor/Model they have.
In the back of the unit has an Input in and Output. I believe they daisy chained all 4 units this way.
I did not open up the unit. It still being used but with a squeezed video.

I don't have any tools to check the caps. Is there a cap kit that could be purchase for this unit ? I did a couple of WG 4600 Arcade Monitors before so, removing and soldering some caps, resistor etc.....would not be a big deal to me.

That MCM unit, how can I daisy chaind all 4 monitors (1 camera being used) ?

Could I use a "T" BNC on the input and daisy chained then that way ?


TIA

[Ken Layton]

Probably not any premade capkits for this monitor. You'll have to open it up, look at the electrolytic caps in it and write them down. Then order what's needed.

MCM Electronics makes a small video distribution amplifier to allow you to loop through the computer monitor adapter:

http://www.mcmelectronics.com/product/82-9355

[Thenasty]

any reason why a "T" won't work ?

[Ken Layton]

You will lose some signal strength that way.

[Thenasty]

Thanks Ken for all replies.


Ok. I took one home and open it up. Hoping a visual check might reveal something but.......
Here are some pics.

[Thenasty]

Did not see any burned/blown off caps or resistors.
The horizontal adjustment, it's max can't get it any bigger.
any thoughts ?

[SirPeale]

any thoughts ?

Yeah...cap it.  It's been mentioned several times already.  Caps don't have to look bad to be bad.  With constant use and age I'm sure they're dry.  It's a basic first step.

[lilshawn]

for 5 dollars worth of caps it would take, it can't hurt to change them all

[Ken Layton]

I would definitely replace all the electrolytic capacitors around the flyback and that vertical output ic that's bolted to that aluminum heat sink.

Here's the free service manual with schematics:

http://www.retrevo.com/search/v2/jsp/downloadPage.jsp?doc=16bd4351e2ee2eda56d041805a2c4d2d&q=Speco+VM-1201B

I didn't have to type in my email there, just enter the digits displayed in the box and you can download it free.

[Ken Layton]

I noticed on the schematic there is an error: it shows TWO C501's and they are both 10 uf @ 250 volts!