Well U3000 Monitor in a Williams Slot

[BallySlotsZ]

Hello Everyone,

 I have a Williams Slot with a Wells garner U3000. Monitor.  Monitor is dead.  I checked the fuse-and replaced it. as soon as you power it up it blows the fuse. Where to start troubleshooting this? Is this problem confined to the power suppy or the Chassie board? I have some repair experience with Electrohome GO-7 monitors. But no experience with these.

Any help and direction would be appreciated.

[KirkLasVegas]

Hello Everyone,

 I have a Williams Slot with a Wells garner U3000. Monitor.  Monitor is dead.  I checked the fuse-and replaced it. as soon as you power it up it blows the fuse. Where to start troubleshooting this? Is this problem confined to the power suppy or the Chassie board? I have some repair experience with Electrohome GO-7 monitors. But no experience with these.

Any help and direction would be appreciated.

Those are usually pretty easy to find...
Check for shorts first...
Check diodes in the power section,
Check electrolytic caps for shorts,
Check Horizontal output transistor for shorts E-B-C
Here is a trick I have used for years. If you cant locate the shorted device there is another way to find the part.
First off USE A ISOLATION TRANSFORMER...
Replace the fuse....
Wire a 100 watt 120 volt regular household lamp in SERIES with the problem monitor.
Turn power on,let run for a few minutes and check for WARM parts. The bad part will have 100 watts of power going thru it
and will get warm. This will NOT burn up boards or do further damage.
Since you are on a iso transformer you are reasonably "Safe", use common sense and check for warm parts with ONE finger or a IR temp probe.

My personal bet?
First... 400 Volt filter caps
Second Horizontal output transistor (one in the heatsink)


Kirk

[BallySlotsZ]

Well,

 Here is what I have checked so far.  All diodes by transformer on power supply section. All testes 0.00 one direction and .457 the other except one.  I assumed this was the issue in the power supply SO I ordered a new power supply board from HAPP Controls. Now I am concerned that this may not have been the problem but the Horz Output transistor may also be a issue.  What readings should I get off of the transistor in diode test.

 I should of checked further. I guess I thought there was another fuse somewhere like the GO-7. There is a fuse that will blow if the transistor is bad. and if the power section goes bad or a cap shorts the main fuse goes bad.

I guess that is what I get for assuming!

[KirkLasVegas]

Well,

 Here is what I have checked so far.  All diodes by transformer on power supply section. All testes 0.00 one direction and .457 the other except one.  I assumed this was the issue in the power supply SO I ordered a new power supply board from HAPP Controls. Now I am concerned that this may not have been the problem but the Horz Output transistor may also be a issue.  What readings should I get off of the transistor in diode test.

 I should of checked further. I guess I thought there was another fuse somewhere like the GO-7. There is a fuse that will blow if the transistor is bad. and if the power section goes bad or a cap shorts the main fuse goes bad.

I guess that is what I get for assuming!

Check the transistor as a pair of diodes. The E-B junction, the B-C junction and also measure it from E-C it should show open.
Silicon devices will show (on diode check) OPEN in one direction, 0.7 Volts in the other.
Be aware that some high voltage diodes and transistors will show from 0.7 volts to as much as 2.8 volts of drop in conduction. This is due to the use of more than one junction to get the higher voltage rating.


Kirk

[BallySlotsZ]

Well,

 I got this finished finally.  Monitor powered up and is now working!!!!   Which has brought up a new problem.  I went through and adjusted everything worked perfect. I played it most of the day.  Later that day my wife went to play it and-- Now the screen is blue.  You can barely see the information on the screen!    Any suggestions?