Wells Gardner D9200 service bulletin regarding lines or dim picture

[Ken Layton]

This is the service bulletin that used to be on ITSGAMES website. I have transcribed it verbatim.

Symptoms:

1. The upper portion of the display shows retrace lines during active video display.

2. The upper portion of the display appears "Dim" and/or "Washed Out" when compared to the lower portion of the display.

3. The lower portion of the display shows retrace lines during active video display.

4. The lower portion of the display appears "Dim" and/or "Washed Out" when compared to the upper portion of the display.

The above symptoms appear randomly, often after the unit has been operating for a short amount of time. The symptoms may appear and disappear during normal operation.

Analysis:

The electrolytic capacitors in the vertical sweep circuitry have failed. Symptoms 1 and 2 are a result of capacitor C306 (2200 uf @ 25 volts) failing. Symptoms 3 and 4 are a result of capacitor C314 (2200 uf @ 16 volts) failing. Both capacitors are located adjacent to the vertical sweep transistor heat sink. The failure is a result of the electrolytic fluid inside the capacitor boiling and/or out gassing, causing the capacitance to decrease. This boiling and/or out gassing also results in a visual deformation of the capacitor case. The deformation is typically exhibited by a "Doming" of the top of the capacitor case.

Solution:

Remove capacitors C306, C308, and C314. Replace C306 and C314 with new capacitors (2200 uf @ 25 volts, 105 degrees temperature rating) and C308 (220 uf @ 50 volts, 105 degrees temperature rating).

My own analysis:

Wells-Gardner used absolute crap bottom-of-the-barrel capacitors which were barely good enough to even make a 90 day warranty period. Remove the junk electrolytic capacitors and install good brands like Nichicon.

[grantspain]

nice one Ken,I am going to work on a 9200 showing similar issues after the weekend
btw do you know why the vendor amusements site is not working?

[Ken Layton]

The forums at Vendor Amusements seems to be working fine for me. I was there just now.

[RichSorr]

Nice! I ran into one of these with random retrace lines at the top in a Maze of the Kings machine. Had to move on before I ever got to repair it.

[southmonitor]

I'm suprised they do not mention C466 (470UF/25V) which is much more frecuent and produces compression of the image at the bottom of the screen. Sometimes they use 470UF/35V; but still is problematic. Also C847, C823 (470UF/25V) on the Power Supply area are really problematic and they produce similar vertical issues with the image. Always replace C847, C823 and C466 with better quality caps for the repair to last.