Powering up issue

[pastiche]

I am having trouble with my Williams Flash project and would appreciate some help!!
When I plug it in most of the lamps on the playfield and backbox light up and the two leds on the CPU board flash twice and then go off. Sometimes one of the numbers lights up on the Master display board but none of the other numerical displays come on.
Putting a coin in makes no difference as the pin ignores the tripping of the wire in the coin mech.
I can't get to the diagnostics without the master display board, so I'm stuck!
The pin came with a spare CPU which I have fitted but it makes no difference. I have also tried installing a different Driver board to no effect.
I just can't get it to go into play mode at all. Does anyone have any suggestions?

 

[Carl Spiby]

Are you getting good voltages from the PSU to the MPU board?

 

[pastiche]

Hi Carl,
The voltage seems OK......

 

[lozpeters]

Have you looked at the MPU section on pinwiki??

http://www.pinwiki.com/wiki/index.php?title=Bally/Stern#The_Single_Largest_Culprit_in_MPU_death

I had the same problem with the m&m pac-man project that i am working on, The LED on the mpu needs to flash 7 times to boot up properly. My issue was battery acid damage on the mpu which had corroded the legs on the chip mount above it, once all the damage was cleared up on the chip mount replaced it all booted up properly!

PinWiki is a great help for this type of project, it has helped me solve lots of issues,

Hope this helps
loz

 

[pastiche]

Thanks loz!
I will take the board out and check it over. Had a quick look at the link you sent to me and it looks as if it has a lot of useful information, so thanks again, much appreciated.

 

[pinballmania]

The most common problem with this design is the power board connectors onto the cpu. Check that the contacts inside the power board sockets are in good condition and still have some spring in them.

 

[pastiche]

Checking the mpu board there is definitely some damage where the batteries have leaked sometime in the past. It is a bit more than I can handle so are there new or second hand boards available or does anyone know where I can get mine repaired?

 

[lozpeters]

Checking the mpu board there is definitely some damage where the batteries have leaked sometime in the past. It is a bit more than I can handle so are there new or second hand boards available or does anyone know where I can get mine repaired?

If you have a spare board to why not give it a go? its actually quite easy one you get started a bit on sanding and soldering fixed mine i only needed one chip which cost a few quid much cheaper than a new board plus you have fixed it yourself!! if the board is really bad you might need a few resistors but theres lots of vides on youtube doing walkthroughs too