(Topic ID: 333475)

Whitestar Dale Jr - no boot U6 suspect

By slghokie

1 year ago

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  • 7 posts
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  • Latest reply 10 months ago by slghokie
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#1 1 year ago

Got a Dale Jr that was in an electrical surge. 2 questions:

1. Boot issues = Lights come on and DMD works (displays Stern Nascar) even when J1 not connected to CPU. L204 never comes on but all the power is good. Have 5V at U6 on IOboard, at CPU watchdog DS1232 and IO DS1232. So 5V seems good.

J1 CPU to IO ribbon is brand new, checked the solder connections on both boards for those connections and they are solid

Output of pin 19 on U6 is low and I believe it is supposed to be alternating (should be the opposite of the input). I believe pin 18 is the input for pin 19 and it is alternating hi/low. Just want to make sure it is the U6 chip and not something upstream from U6. I have a replacement U6 and socket so can shotgun it but wanted to make sure I narrowed it down properly.

EDIT: for good measure Pin 1 tests low (clear) and pin 11 is pulsing (clock)

Was basing my analysis on this:

Reset Circuitry:
The I/O will reset in three (3) cases:
1. The CPU is in reset. The CPU’s reset signal is fed into the I/O through connector J1 and forces the I/O into reset.
2. The 5v supply has fallen below 4.75v.
3. The watchdog is not being fed by the scanning of the light matrix. More specifically Pin-19 of U6
must be toggling once every 50ms to prevent the watchdog from resetting. The scanning of the light matrix is controlled by the CPU through J1.
LED L204 shows the reset state of the I/O Board. If this LED is not lit either the 5v DC is below 4.75v or the CPU/Sound Board is holding the I/O in reset. If the LED is flashing this means that the watchdog is not being feed by the CPU/Sound Board and the I/O is oscillating into and out of reset. If the LED is continuously on the board is out of reset and communication from the CPU to the lamp matrix is confirmed. Testpoint Blanking is the actual reset signal on the I/O Board. A low voltage indicates that it is in reset this will turn off all Solenoid (Coil) Drivers, Flash Lamps, Lamp Matrix Drivers, Auxiliary Outputs and Flipper Outputs. A high voltage indicates that it is out of reset and normal operation can take place.

2. = The other odd thing is L200 and L202 stay lit well after the power switch is turned off...is that normal?

First DMD/whitestar. Usually work on EM's and early Bally/Gottlieb SS

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#2 1 year ago

For my question 1 I found this chart in the data sheet. Seems I have the first combination. So question is what is the correct boot combination of CLR, Clock, and D for output on Q? If so then it could be a problem before the U6

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#3 1 year ago

Mapped out a plan to validate and started with CPU DS1232 sending to IO board. Found Q10 on the CPU was shorted but replacing did not change boot status or L204. Q10 has Low coming in from CPU DS1232 and comes out as hi/low sent to pin 13 on CPU to IO board then to pin 1 of U210 DS1232 which is the pushbutton reset.

Not sure what should be coming out but was basing it on this....

The DS1232 provides an input pin for direct connection to a pushbutton (Figure 2). The pushbutton reset
input requires an active low signal. Internally, this input is debounced and timed such that RST and RST
signals of at least 250 ms minimum are generated. The 250 ms delay starts as the pushbutton reset input is
released from low level.

U210 IO DS1232 pin 5 is connected to L204 so that is the signal I am trying to get to go. So questioning if the CPU watchdog is sending the right PBRESET. If that is OK, then leads me back to U6 on IO board as pin 19 sends ST signal to U210 IO DS1232 which outputs pin 5 which goes to L204 (I believe). That should get me to boot, depending on what U6 is supposed to send assuming the U210 IO DS1232 is working properly. If anyone can tell me what those flows are supposed to send hi/lo/pulse that would be appreciated.

My U210 IO baord:
Pin1 Hi/Lo
Pin5 High
Pin6 Low
Pin7 Low (I think this needs to have a hi/lo pusle based on datasheet: "To guarantee
that the watchdog timer does not timeout, a high-to-low transition must occur". I may try the changing the pin3 mod so it is not floating but dont know that will fix this.

U6 Pin 19 is low

#4 1 year ago

Just found these 2 issues on the IO board. Was able to solder blob U211. That actually gets me alternating hi/lo on pin 1 of U210. Then I see missing R271 which should be connected to 5v. Will replace that 10k resistor and see what happens. Still no boot but finding things to fix

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#5 1 year ago

Replaced R271 on the IO board and no change. Headed back to U6 to figure out if the inputs are good

5 months later
#6 10 months ago

Socketed and replaced many more 245 IC's that had legs clipped on CPU. Installed NVRAM. Bought a new game ROM and replaced that on CPU. Replaced the PAL chip and that drove a change in what it does on power up. Now L204 blinks/flashes (GI and relay do the same) and the reset button on the CPU board now works. I no longer suspect U6 on the IO board. That seems to be pulsing as it should and the L204 blinking seems to indicated CPU issue. Still no boot, still nothing on the display. if I unplug the display from CPU and boot with just IO board I can see Stern Pinball logo on the DMD, so I think it works but not with the CPU. Anyone have any ideas.....bad CPU rom, wrong jumpers, U214, bad watchdog chips? Ribbon cable was already replaced between CPU and IO. No batteries on it when I got it and I do not see any corrosion. Was in an electrical storm and blew up parts on the CPU. All voltages and fuses good on IO.

#7 10 months ago

On advice of Coin-Op_Cauldron I checked all the CPU U414 pins for short to ground. The only pins that did were the actual ground pins. I also put in a new U209 and socketed and replaced U214 but no change. Still blinking L204 on the IO board and lights/relay in synch with flashing.

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