(Topic ID: 235673)

Stern 7digit displays blank


By Sonora70

3 months ago



Topic Stats

  • 18 posts
  • 6 Pinsiders participating
  • Latest reply 3 months ago by slochar
  • No one calls this topic a favorite

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#1 3 months ago

Working on a Flight 2000 project. All of my displays are blank minus one. I have moved it around and it continues to work in other player locations but the others do not. The displays look good and there is a "glow" in the corner when the machine is booting up but they remain blank. I saw a link here on pinside that explains how to test the display and it mentioned shorting one of the transistors on a stern display but I cannot find the link anymore. Can anyone help? Thanks.

#2 3 months ago

The glow would indicate you have HV to the board. I would really scrutinize the solder joints on the header pins before you go any further.

Reflow any pins that are questionable

#3 3 months ago

I have reflowed the solder joints. I think the link I'm looking for is specific to Stern. The displays look good, hate to throw them out. 3 of the 7 digit and the 6 digit credit display are blank. I've tested all the transistors and the test fine, not sure that's always reliable.

#4 3 months ago
Quoted from Sonora70:

I have reflowed the solder joints. I think the link I'm looking for is specific to Stern. The displays look good, hate to throw them out. 3 of the 7 digit and the 6 digit credit display are blank. I've tested all the transistors and the test fine, not sure that's always reliable.

bad decoders not getting latched? can try a new cd4543 or mc14543 chip on a non working bad display.

triple check the header pins on the no working displays. The solder joints notoriously crack on these boards.

#5 3 months ago

What's the HV measuring? Check it's not set too low. Typically 190vdc but can be a slightly less.

#6 3 months ago

So this is the reference for display repair. http://stevekulpa.net/pinball/bally_disp6r.htm

Test the 100k ohm resistors and make sure they're good. They are underrated for this job and may be open.

It's also time for you to bust out a schematic. Stern's can be numbers different so find a stern schematic of you don't already have one.

At this point once you can verify you have power to the test points (and that it is high enough ~190VDC) then you need to look at the digit enable transistors and the decoder.

#7 3 months ago

The 100k resistors only become under rated when a digit locks on and is no longer being strobed. When the 100k resistor open burns there is usually a reason it happened... like the CPU fudged up at some and locked on a digit or the level shifter transistor for a digit went short which locks on a digit. I wouldnt think every single 100k resistor on every single non working display burned open... i guess its possible, just not very likely.

#8 3 months ago

Checked all voltages, finally decided to try my Alltek mpu board from another game, all the displays are working. Obviously something going on with my mpu board. Thanks for the help.....now it's mpu time! I previously assumed that because it if completing it's boot sequence it was good.

#9 3 months ago
Quoted from Sonora70:

Checked all voltages, finally decided to try my Alltek mpu board from another game, all the displays are working. Obviously something going on with my mpu board. Thanks for the help.....now it's mpu time! I previously assumed that because it if completing it's boot sequence it was good.

DIP Switches setup for the right game? Also, isn't there an additional MPU-200 jumper or something on those boards, to switch between using dual-5101 or single 5101 type of setup? Something must be getting hosed with some display data then or too low of current of some signal. Interesting one 7-digit display does work.

#10 3 months ago
Quoted from Sonora70:

Checked all voltages, finally decided to try my Alltek mpu board from another game, all the displays are working. Obviously something going on with my mpu board. Thanks for the help.....now it's mpu time! I previously assumed that because it if completing it's boot sequence it was good.

hrmm i thought the issue was moving with physical the display.

If the issue stays at position... like player two always out, I would be checking the latch strobe signal on the MPU. The MC14502 or CD4502 can go bad and are what controls the display latch strobes.

#11 3 months ago

DIP Switches setup for the right game? Also, isn't there an additional MPU-200 jumper or something on those boards, to switch between using dual-5101 or single 5101 type of setup? Something must be getting hosed with some display data then or too low of current of some signal. Interesting one 7-digit display does work.</blockqu

Thanks for the tip. Researching that now. I'm needing to find the dip switch settings for the MPU-200 Flight 2000, not seeing them in the manual. There is a jumper setting on the Alltek board which I did before I installed in the game to test. If anyone could take a good picture of the MPU-200 dip switch settings for Flight 2000 I would really appreciate it. I feel like I need to verify those before I go any further.

#12 3 months ago

Thanks for the tip. Researching that now. I'm needing to find the dip switch settings for the MPU-200 Flight 2000, not seeing them in the manual. There is a jumper setting on the Alltek board which I did before I installed in the game to test. If anyone could take a good picture of the MPU-200 dip switch setting for Flight 2000 that would be great. I feel like I need to verify that before I move further.

#13 3 months ago

Flight 2000 dip=01010000

#14 3 months ago
Quoted from slochar:

Flight 2000 dip=01010000

Thanks!

#15 3 months ago

Update, based on pinwiki, pin 10 of J1 should read 5v during boot up and then begin alternating between 1v and 4v during attract mode. I just tested on the bench and it is staying at 5 v after boot up, no pulsing. I assume I may be getting close to my problem if this remains true using a bench test?

"If the blanking signal for the displays is stuck high or low on the MPU then the displays will remain blank. To check the blanking signal use your DMM or logic probe on MPU J1 P10. During the flash tests it should remain high (5v on DMM). Once attract mode begins it should begin pulsing (DMM will show somewhere between 1v and 4v). If the blanking signal is stuck high or low examine the blanking circuit including CR6, U14, U20. It could be the PIAs but unlikely as the power on flash test should check that the PIAs changes states. I have seen CR6 be open and cause displays to be blank. "....pinwiki

#16 3 months ago

That's actually for the Alltek board. I think I may need the switch settings for the MPU-200 board.

#17 3 months ago
Quoted from Sonora70:

That's actually for the Alltek board. I think I may need the switch settings for the MPU-200 board.

Ipdb.org has the F2K manual on its website. All your dip switch settings and options are on the first 14 pages of the manual.

#18 3 months ago
Quoted from Sonora70:

That's actually for the Alltek board. I think I may need the switch settings for the MPU-200 board.

Game should boot regardless of your dip settings on an mpu200 board - the dips are for game options instead. If they are all off, it will automatically go into self-test/burn in, which is convenient to be able to test the displays right away. Flight 2000's bootup sequence is slightly different than single-ball games in that it searches for all 3 balls first and will fire the ball walker sequence looking for them if it doesn't see them right away.

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