Paperboy Garbled Audio and No Red in Monitor

PaperboySymptom 1:

No red in monitor

Process:

  1. Tested the usual culprit, transistor in neck board, it worked fine.
  2. Followed schematic to find where red is handled from pcb to neck board and found a bad transistor located at Q203 (2SA562Y PNP Transistor).
  3. Replaced it and Red came back.
  4. However, colors were still muddy and not where they needed to be. Used my B&K 470 rejuvenator to clean the monitor guns and colors came back nice a bright.

Fix:

Replaced Q203 (2SA562Y PNP Transistor) in monitor chassis

 

 

Symptom 2:

Right audio had bad crackle in sound during sound test. All speech was garbled.

 

Process:

  1. Swapped Pokeys – no change
  2. Used audio testing tool to test output from speech chip – audio is fine
  3. traced audio to AR board
    1. input audio is good
    2. output audio is bad – problem is in A/R Board
    3. Tested voltages and found a drop in voltage and isolated the problem to a bad capacitor (pulled suspect components and tested out of circuit)

Fix:

Found a shorted glass ceramic capacitor on A/R Board on the right audio channel line. Capacitor located at C8 (.1uf 50v glass encapsulated ceramic capacitor). No more garbled speech

 

Symptom 3:

Right audio was very loud would not turn down with when volume was adjusted

Process:

  1. Tested volume pot located in the coin door and it worked, fine but suspected cold solder joints for the right audio channel due to fluctuations in audio when cabled were moved
  2. Re-soldered cables and audio volume worked correctly on both channels

Fix:

Re-soldering of cables to volume pot located on coin door.

 

 

Links to documentation:

Monitor Manual and Schematics – Atari Monitor TM-281 4th Printing WG 19k4915 19in Med Resolution

Manual – Paperboy_TM-275_1st_Printing

Schematics – Paperboy_SP-275_1st_Printing

Operation Thunderbolt

Bought this as non working. After going to get it and turning it on before I bought it, I felt I knew what the problem was, bad power supply.

Symptom:

Monitor turns on but stays black, does not play blind.

Fix:

Power supply was not providing 5V. Replaced switching power supply, fixed problem.

Machine worked flawlessly until sold.

Battlezone Repair Log

We did it! We decided that we wanted to go through all the pain and suffering that many of my KLOV brethren go through on a regular basis and decided to get a non-working “it was working last time I turned it on” Battlezone.

I’m a big fan of battlezone so I was really excited to get this guy back to the arcade. Plugged it in and let’s see what we got.

First things I notice:

  • 5v LED on main board is on
  • Spot (soul) killer LED on monitor is on (OH BOY!!)
  • 5v LED on aux PCB board is NOT on hmmmm
  • Dot on screen (monitor is working hooray)

Shut it down and let’s dig in.

Pull out the trusty multimeter (I call him mike the mechanic…don’t judge me) and start taking power reading. Most of the readings are ok, but some are high while others are low. I normally like to rebuild the AR board and change out the big blue capacitor in the power supply right off the bat so I go ahead and order those items and start down that path.

I worked with a buddy and did a trade for working boards. Game is up and running!

Galaga is almost done

I picked up this Galaga about a month ago. It was in great working condition but I wanted to make some significant changes. Overall paint job was textured, but it was in decent shape so I figured I could live with it. When I got it, someone had replaced the original 19″ monitor with a 25″ monitor which required them to remove the top and bottom of the bezel to make the monitor visible. I really wanted to bring this game back to original as much as possible so I decided to put in a 19″ monitor. It just so happens that my good friend and fellow S.M.A.C. member purchased a group of machines and one of them was a non working Big Event Golf (never heard of it). However, lo and behold it had a beautiful Galaga bezel in it. I knew that he was looking for a 25″ monitor so I traded him my monitor for a 19″ and the bezel.

I cleaned up the bezel and removed a big ugly Big Event Golf sticker on it. It is in terrific shape and it looks great in the machine. I ordered some new side art (it had none) new kickplate art and a new control panel overlay (CPO).

Changing monitors is never fun, but it only took a few hours and a few cuts, but we got it in and it looks fantastic.

Quick video of the game play on the new monitor:

Next up: CPO replacement.