Recent content by Minnesota 13

I was answering the question to what kind of meter I am using not debating the functionality of a digital meter in measuring high frequency voltage. I thought about measuring the current draw to determine the voltage. The tube heater resistance is spec at 2.5 ohms. The heater winding on the...

My digital meter is true rms. But how about trying a 6V lamp to test it or will it draw to much current vs the CRT heater? The HV is good as I hear the crackle at startup and when grounding the HV at the tube a nice pop. I failed to mention that I replaced all of the electrolytic caps and...

New black level pot. But I will crank it up.

Using regular voltmeter measuring heater voltage. Sold my scope. There is no tube neck glow. B+ and HV OK. Otherwise the the CRT is dead/dark. With the flyback heater input connector removed from the neck board the heater resistance is 3.5 ohms - neck board connected to the tube. Includes...

No neck glow but HV. Measured the heater voltage looking for 6.3 but it is at 1.5VAC. So do I need a complete replacement flyback?

Have you sold the zoom button thing?

Turns out the power resister R53, 4 ohms to ground confuses the debugging. Looking like on the of the lifted components is faulty. Consider this resolved.

7VAC fuses are blowing. Apparent short on the circuit board between 7VAC inputs and ground. All new electrolytic caps. Problem existed before new caps. All diodes check OK in circuit. Lifted 6.2 zener D9, problem remains. Removed D44VM4 and 78GUIC problem remains. Diode D6 tests good...

I am not a monitor fix-it person. I acquired the Nanao MS8-26SU as a non-working monitor in a non-working game. I found fmonitor use F902 a 2A fuse blown and previous "tracks" of a previous owner attempting to resolve the problem or previous problems such as the FBT Screen adjustment maxed out...

I have the dip switch set for one credit per coin. It is confusing as the coin switches, the free credit switch, the start switch, the ball hole switches (most of them) including the ball home switch, joy sticks all work under the diagnostic test program. This verifies that the board to...

Working a project Ice Cold Beer. Rebuilt power supply and found a reverse wired big cap. Also 12VDC unregulated was reversed to the main board. Also I replaced one of the large bridge rectifiers. Game boots. Goes into attract mode with display reading zeros and the star lamp illuminated...

DE Version 3 Schematics Use the DE Checkpoint manual found on ipdb.org. The only difference is that Checkpoint has the small DMD. The boards are all the same. The RAM size may be different, in that Simpsons may have a small RAM. I usually just re-socket for the larger chip and replace the...

Problem Resolved I found the problem. The yoke connection to the PCB was faulty. The plug wasn't fully seated and was limited by tight wires that probably over time pulled the plug from being fully seated. Easy fix when the problem is found...thanks for pointing me in the direction of the...

If you have a signal generator or can produce an analog tone of say 1kHz you can inject the signal in and determine if the final amp stage is functioning and move inward if you find all is well. Or you can use a small transistor radio to generate a signal, ground the appropriate side of the...

Tap anywhere and it fixes the problem Gonna be a tough thing to find. A light tap on the frame restores the picture so it looks like it's take some time or it might be easier to reflow solder every thing. Barry