Pole Position Repair Log

Okay, the Pole Position PCB is again on my desk. As told it has some issues for the graphic output. This was the starting point.

Color is red is defect somehow. Replacing PROM at 11E for RED 136014-137 (82S129)

After that fix the picture still has some issues. Every second line is missing on the sprites.

So I dig out the manual

Table 2-1; Seite 2-2
http://www.arcade-museum.com/manuals.../P/polepos.pdf


Checked the EEPROMS
http://www.solvalou.com/subpage/arcade_roms/P/polepos1
13N and 12N are 2764, 8 * 8Kbit (small cars and signs) OK
6N (background) und 11N (All Cars and signs) sind 2732 8 * 4 Kbit OK

Then I found this info
http://forums.arcade-museum.com/showthread.php?t=61451

I checked schematic 15A Motion Object Line Buffer. Control Logic for Lines is in 74S158@8D (control logic) and the lines are recombines in 74S298 (recombines lines). Line Buffer is needed in SRAM 2148L-2 @ 9F, 10F.

9F and 10F are 55ns RAM; 137199-00, used 2149 ones.

After replacing the SRAM the PCB was fine again.

Picture of replaced connector edge.

Picture of PROM 11E for RED

Replaced SRAM on 9f and 10F. Each replaced IC gets a new socket.

See the perfect sprites :)

Green Beret PCB Repair Log

Green Beret, one of my favs... but one day the little soldier won't go up the ladder anmore..









So I`ve desoldered IC 74LS253 and then it worked again.

Repair Log STTNG Star Trek : The Next Generation Flipper Pinball DMD Display outage

Hey,

had yesterday some time to repair my pinball machine ST:TNG.

After doing some cleaning the DMD Display was not function anymore. No problem, I just replaced R6 and R13 on the DMD controller PCB.



:) Just kidding. Tons of reading, threads, tools buying later I was able to fix the problem.

Tools needed:

- Solder Iron
- Desoldering wick
- ESR Meter capacitor testing tool (Great Vid from Level42)
- Multimeter

Background Info:

WPC schematics manual Page 11
Kompedium Fehlersuche DMD Display, Page 13
ESR Meter

Testing steps :

Exchanged Display - still nothing

Step 1
Measured DMD Controller PCB
J604 -

- Pin1 to GND: -16V (should be -70V - -125V, mostly 114V)
- Pin2 to GND : -9V-10V(should be pin1 voltage level - 12V) (against Pin1 ca. 6V, but should be 12V)
- Pin 6,7,8 OK (5V, 12V, 62V)

Pin1 without DMD connected vs gNS about -40V

Apparently Pin1 and Pin2 voltage level are not correct

Step 2
So go ahead to
J605
80VAC between Pin1 and 2 -> OK
100VAC between Pin3 and 4 -> OK

Step 3
Measured Fuses -> OK

Step 4
Measured BR2 - Do measure R13 both ends voltage level, should be 130V -> OK

Step 5
So go ahead
Kompedium Fehlersuche DMD Display, Page 13

Check parts in Blue box.
Measured with ESR70 all capacitors, all ok.
Measured R6 and R13 -> Ups, some MEGAohm.

Replaced R6 and R13 with 68Kohm instead 47kOhm 1/2Watt, had no other ones in stock.

DMD Display works fine again.