Replacement Zaccaria MPU 1B1165/2 - Unpopulated PCBs

[Homepin]

Well - the sample board arrived from a very generous member and we have started to lay it out. It's very early days yet but we have got all the IC's in place and have discovered a few issues already to work through. Lots more to do......................I'll update the thread as we progress.

[Pop Bumper Pete]

So we will now be able to consider adding Zacs to our collections?

Coolies

[pinnies4me]

Fantastic initiative, I'm sure the guys on the Zaccaria website will be all over this.

[Strangeways]

I think Gavin likes you very much, Mike 

I've never owned a Zac..

[Mr Pinbologist]

does anyone REALLY know how to repair these SS Zacs??  

they're GREAT when they work but are absolute BASTARDS when they dont

sorry for that little outburst    its just that a mate of mine has two that have been nothing but trouble for both him AND me,
i will definitely be keeping an eye on this thread, could be the answer to my mate's problems (and mine coz IM the sucker who is stuck with working on them) 

[Retropin]

Problem with fixing a Zac is that pretty much everything is interelated. Its not like a WMS board where switch inputs are this little circuit and, BCD outputs this little area etc... a zac can have a problem with one output on a 74LSXXX and the resultant fault can be seen on almost everything else..... really plays with your head!

[Ric]

Dave Gersic is the only guy I know who really understands Zac's

[Homepin]

One of the IC types used on this board is a CA3081 which is practically impossible to find these days and there are seven of them on this board!

In reality this IC is made up of 7 pretty common transistors manufactured into a single IC package for ease of production assembly.

By replacing each of these IC's on this new board it can then be assembled using common transistors such as BC547's etc. This means the end user will need to install a total of 49 individual transistors but that is far better than trying to locate obsolete devices. It also makes fault finding in the future a lot easier.

You can see that IC26 has been replaced here with 7 transistors (ringed in white). Six more to go.........

[humpalot]

http://www.futurlec.com.au/test13.jsp?category=LinearOthers&category_title=Linear%20Others&main_menu=IC&sub_menu=ICLOTHERS

sell the CA3081N for $1.47

Love seeing some boards getting made 

[Homepin]

http://www.futurlec.com.au/test13.jsp?category=LinearOthers&category_title=Linear%20Others&main_menu=IC&sub_menu=ICLOTHERS

sell the CA3081N for $1.47

Love seeing some boards getting made  

I tried ordering CA3081's from Futurlec and the reply was "no stock"

Besides, it would be pretty foolish to make 100 new PCBs knowing that somehow - 700pcs of this chip will need to be found from somewhere to build them.

Even when you find someoe with stock they often only have a handful anyway......

[Skybeaux]

Futurlec told me that they don't have any either , and they couldn't get them anymore.

I only have about 50 of the 3081's , they're also used on the early Bally driver boards which is what i use them for.

I think what your doing using the discrete transistors is a excellent idea!!

[bossgp]

Great idea, nice to see an interest , have only ever owned one Zaccaria and that was Magic Castle, never had an ounce of trouble with it while I owned it.

[63wizz]

One of the IC types used on this board is a CA3081 which is practically impossible to find these days and there are seven of them on this board!

In reality this IC is made up of 7 pretty common transistors manufactured into a single IC package for ease of production assembly.

By replacing each of these IC's on this new board it can then be assembled using common transistors such as BC547's etc. This means the end user will need to install a total of 49 individual transistors but that is far better than trying to locate obsolete devices. It also makes fault finding in the future a lot easier.

You can see that IC26 has been replaced here with 7 transistors (ringed in white). Six more to go.........

Maybe you could do a small mod board Mike to replace the CA3081 for people that need this chip but cant find it.

ian

[Homepin]

One of the IC types used on this board is a CA3081 which is practically impossible to find these days and there are seven of them on this board!

In reality this IC is made up of 7 pretty common transistors manufactured into a single IC package for ease of production assembly.

By replacing each of these IC's on this new board it can then be assembled using common transistors such as BC547's etc. This means the end user will need to install a total of 49 individual transistors but that is far better than trying to locate obsolete devices. It also makes fault finding in the future a lot easier.

You can see that IC26 has been replaced here with 7 transistors (ringed in white). Six more to go.........



We did investigate that concept but dismissed it because there are seven of these chips on the board. To hang seven 'daughter boards' off the mainboard is simply asking for unreliability issues. At the end of the day they are simply BC547 transistors anyway so it's not really a problem.

The bottom line is that we may end up having to supply the parts to build the majority of these blank boards and it will be impossible for us to find 700 of these chips - BC547's are available anywhere and are dirt cheap!

This is just one of the changes we feel must be made for this project to be worthwhile in order to keep these machines going.

Maybe you could do a small mod board Mike to replace the CA3081 for people that need this chip but cant find it.

ian

[63wizz]

Cool Mike, didn't realize there was 7 chips to replace.

Ian