A surfactant is essentially a detergent. Pick your favorite cleaner. Nothing harsh is required. I use Simple Green. You can probably get away without using a surfactant.

This is what clips will look like.

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The resistors required for adjustable are R1 and R2. Both need to be 1% to produce more tolerant voltage output. When used with a fixed output only R2 needs to be installed. The silkscreen values on the left are the adjustable values and the right are the fixed values.

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The spacing between the leads is 7.5mm (7.62mm). You can always bend leads but if there is a component you find that is compatible look for lead spacing that reduces the amount of lead bending.

Got these boards finished on Friday and verified on Saturday. Most are now in the mail system.

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Got this board built in between packing of those boards. Or is it the other way around (i.e. pack boards in between building this board)?

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I built a concatenated single ROM (on board support) as well as a concatenated multiple ROM (select daughter board) and wrote them to EPROMs. The ROM select daughter board is built. Nothing has been powered on. I need to figure out how I want to test this. I haven't done that yet. I will probably pull out my Siegecraft boards for the solenoids and build small, quick cables for the lamps and switches. The universal numeric should work for the 7-digit albeit with the known error and I guess I'll see how the 6-digit works out (I know there will be an error with it).

The following phases must pass before everything is declared good.

1. Bench verification of solenoids, switches, lamps and display - i.e. digital logic, inputs and outputs.
2. DIP switch input for System 3. I have no idea how this works so I will have to figure it out.
3. Cabinet fit (mounting and cable to header connections/locations) for one of each System 3, 4, 6 and 7 backbox configurations.
4. Actual play testing in a machine.

I can throw it open to those who are adventurous once I complete step 1. That's the most critical phase as far as base functionality goes.

I have no estimate for when I will complete step 1 but after spending weeks of almost non-stop building of big boards a few days break from that is refreshing. It also works out well as I wait for some components to come in that I am running short of for the current batch of big boards. I will probably work on the verification plan when I need a break from building.

The next batch up is three 11s and one 9. See you in about two weeks.

In case it wasn't obvious ... of all the tasks I do ... packing and shipping is the most disliked. I really don't like packing and shipping. It's even more mundane than building a board. I have a few boards sitting in my pack queue so I apologize. I just spent the last week spitting out these that now are ready for verification. I can't keep putting off the packing so it will happen shortly.

I do also need to divide time with component acquisition. Supply chain problems are affecting me so I try to stay ahead of potential issues. I don't always succeed. There are two components that I am having a little trouble sourcing at the moment. I do have workarounds though. I haven't hit the brick wall ... yet.

Built these displays last week. Waiting for verification. As I have limited desk space I like to batch things so I will batch the verification of the boards following with these displays.

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These two are System 11 (nothing) boards.

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This is a special System 11 board set. It's primarily a System 11 (nothing) board but includes another DAC board (configured for 11B) and the special solenoid status (LED) board. These are options and the status board is not really advertised. I call this configuration "universal" because with all of the included daughter boards the board supports all configurations of System 11.

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And another System 9 board. I had to spin this board to use the relay daughter board. That's one of the components that I am having trouble sourcing.

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Finally ... I had this prototype made. I had previously made an attempt at a unified System 11 power supply but the board has audible hum. I thought it was related to the ground but it might be related to trace routing. So I threw out the early System 11 aspects and tried again. A downgrade to prototype. The board is really simple so it's puzzling to me. I'll put this in my Rollergames when I next get the chance.

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Picked up a few boards for repair. One just need verification that will happen tonight with the rest of the boards above.

I think I can see the light at the end of the tunnel (zero work queue) but it still feels quite far away. After I get the outstanding boards verified, packed and shipped I intend to take a small break to fix some board issues and restock some others before building the next big batch (WPC-89 power driver boards). The System 3-7 unified board is still on the backburner. It does need some research on my part (as far as testing goes).

Thanks for all the kind words!

I finished a pack batch over the weekend and I have a small number of left over boards that are a part of orders that were waiting for components that arrived yesterday.

I also got some boards in (locally) that needed repair. I am always scared when I see previous repairs. They are often (not always) poorly done and have residual problems. I always suspect prior work/repairs and though I don't like being so cynical it's unfortunately proven to be true quite often. This particular board was interesting. The short (no pun intended) of the problem was that whoever did the repair tied D1 and D6 together so whenever solenoid 2 fired then both solenoid 2 and 7 would fire. Whenever solenoid 7 fired both solenoid 2 and 7 would fire. Same with solenoid 10 and 15 as well as 18 and 23 as well as 26 and 39. It also wreaked havoc on the lamp matrix as you can imagine. I usually like to clean up repairs better than this but the use of the SIP sockets means I won't touch it and only do the minimal amount of work. I stay far away from repairs that use SIP sockets.

Before:

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After:

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In between these small tasks I spent some time on the unified System 3-7 board. It was definitely rushed as there are some interesting problems. Ultimately there's a fundamental problem in this REV-00 that will prevent System 7 boards from working at all. System 6 boards should work but alas ... neither of them work.

Technical summary of state for those interest:

• The address for the SRAM region of the address map is not correct. Williams made a change to System 7 that I didn't factor in. This is due to my ignorance of System 3-7 in general. It also definitely does NOT help that I do not have working System 6 or System 7 boards as a control ("gold standard"). I may eventually need a set if I can't figure things out but I'm not at that stage ... yet.
• The diagnostics for System 6 (two LEDs) and System 7 (digit) are not correct. They're reversed. I read "7400" and thought "AND" but it's actually "NAND" so the BCD to the 7447 is inverted. The System 6 LEDs are reversed as well.
• The good news is that the Leon works. That means the CPU is executing and the basics of address decode is working.
• The bad news is that the ~BLANKING signal stays low (active) and there is no activity on the strobe lines. This is a good indicator that the software is either hung or in some form of infinite loop. The error in SRAM mapping should not affect System 6 execution so this is puzzling to me. This needs more investigation.

The (Williams) universal numeric display works but has a signal input error. I swapped the BCD inputs so there is a workaround that does not require a new board but there is also some other small issue I need to investigate on the board that may require a revision either way. A feature I (attempted) to add to this board is brightness adjustment and it does work but requires more components. The workaround (cable) is shown in the following image.

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I generally take my time when trying to figure out problems. I don't always get things immediately and sometimes it takes a while for the penny to drop. This is why things take time for me to do. I am guessing that I will spend a little more time looking at some of these outstanding issues to make a decision on if I need a new board revision. I like to get board fabrication orders sent with priority because while being fabricated I can do something else. If I reverse that order of operation and build first before fabrication I can potentially spend time waiting for fabrication that could be used in other better ways. A little like overlapped I/O for those familiar with old Windows programming.

<tl;dr>

For those that like to read large wads of text with nothing better to do and are interested in the differences between System 6 and System 7 SRAM ... read on.

• System 6 has two physical RAM ICs of $0080 (128) bytes in size mapped at $0000-$007F and $0080-$00FF. They form a single logical unit of $0100 (256) bytes (JBOD in RAID terminology). The CMOS IC is $0100 (256) nibbles (4 bits not 8 bits) used to hold settings and is mapped at $0100-$01FF.
• System 7 has two physical RAM ICs of $0400 (1,024) nibbles in size mapped at $1000-$13FF. Each nibble of the byte is written to different units (striping in RAID terminology). The CMOS IC is the same ($0100 nibbles mapped at $0100-$01FF). To maintain compatibility with System 6 the hardware maps $0000-$00FF to the first $0100 bytes of the regular RAM - in essence a double mapping (two addresses map to the same physical location).

This is the detail that I missed in REV-00. I just mapped everything at $0000 assuming the software knew that $0100 was the CMOS location. The problem with this implementation is that writes to $1100 will overwrite the CMOS at $0100 as they aren't directed to different physical locations. This is why System 7 will never work on the REV-00 board and requires a revision.

</tl;dr>

As mentioned above I do not plan to spend too much time on this as I still have outstanding big boards to build. I just need to take a small break from that to recharge. If you're still waiting for a board I will resume building within a few days.

It's more difficult to remove them cleanly (at least for me). In my eager early repair days I would try anything and everything but SIP sockets always left me with more pulled pads and traces than anything else. In my experience it is easier to remove an IC directly soldered into the board than it is to remove a SIP socket. I must be doing something wrong (technique). I don't like repairing traces so I avoid causing the potential damage in the first place.

I have done this. I discovered this in my many experiments to remove them without causing damage. It's just labor. This is a great technique for sure. This particular previous repair wasn't too bad in that there was only one pulled trace/through-hole. I have dealt with much worse previous repairs and my usual policy with previous repairs is undo the entire repair so I can see what I am dealing with. If I don't do that it would be akin to "the blind leading the blind".

Typically ... a few things need to be in place before I go down this road.

• Have some experience with the system involved. Not required but desired.
• Research the various machines that used the board (set) to understand the different revisions. Required.
• Research part availability and if some are unavailable what can be used as a substitute. Required.
• Obtain sample boards for required component placement (dimensions and mounting holes). Rob my machines, get loaner boards (will be returned) or get donation boards (typically a trashed board that does not need to be returned). Required.
• Have some way to test the system involved (bench rig or pieces that can be used). Not required but desired.
• Have a way to test the result in a physical machine once verified on the bench. Required.

Assessment of the current state (according to me).

• I only have one machine (Lord of the Rings) and it's on loan to a friend. It is also a Whitestar (WS) MODIFIED.
• I have done little research on the usage of the board set - i.e. I don't know too much about Stern WS machines.
• The boards use BSMT2000 and some PALs that need some additional research. The modified uses an ATMEL that I know nothing about.
• I would only have access to the modified WS and not any original WS boards.
• I do not have the DMC to be able to see the display output from the CPU board.

I think you can see there's a lot of work to be done here. Board acquisition is going to be the biggest challenge. It wasn't on my list and I was about to start winding down on going hard with making more boards. I just checked and I made my first board fabrication order 3 years ago. That means I have done nothing on machines for 3 years now.

I still need to finish off some boards that are incomplete - i.e. still in development or have issues that need resolution. I am a one man show so I do ALL the tasks listed above in addition to actually working on the board schematic capture and board layout. I have reached the point where there has to be decent demand or the board has to be small to want to do something new.

I know the comment wasn't directed at me. I figure it was referring to another thread.

The following is not a reply to this comment but a general comment.

I have never been to TPF. At the beginning of 2020 I was considering going but we all know what happened early 2020. I have not considered going since and only just got the courage to get on an aircraft over the holiday season. I have been (what could be considered) a fixture at the Northwest Pinball and Arcade Show in years past but I am still on the fence about this year. I haven't seen much talk about "repair parties" or local enthusiasm. Maybe I'm just not on the social groups where this is happening (i.e. no Fakebook for me).

Been busy trying to finish the last of the current big boards. I have a bunch of smaller boards before I need to take a hiatus to tend to long neglected things.

• If you're having trouble locating the correct component let me know which ones.
• If you're having trouble locating a merchant with the component stocked that's a tough one.

The supply chain issues are affecting me as well. I'm lucky that I bought a reasonable number of components and often check merchants for heavily used components to keep my numbers up. I have only run out of some specific hardware components that I am able to work around by using substitutes.

Agree with this. The IC is used in a purely digital logic circuit so HCT should be compatible.

I avoid Jameco. I got burned once and haven't bought from them since. I, personally, don't recommend them. Others may have had more success. YMMV.

Yes. I was going to suggest this but Chris beat me to it. "Naked" headers are perfectly fine. The OEM board used these. I like the box headers because presbyopia can wreak havoc on cable insertion.

Ding ding ding. We have a winner.