PCBWAY.COM SPONSORED THE NEW PCB, BOARD ARRIVED TODAY
I received 5 printed circuit boards for my new design of a controller card to insert into an IBM 1130 system in order to connect an IBM 1627 Plotter. PCBWAY.COM had contacted me on this blog and offered to sponsor some printed circuit fabrication for upcoming projects. I thought this project would be a good opportunity to try this out for both them and me.
IBM makes a card that is plugged into a logic compartment in a specific slot to add support for the 1627 to the configuration of the system. It is built with their Solid Logic Technology (SLT) components as a double width card. SLT cards plug into a socket on a backplane using a connector that has two rows of 12 pins. The double width SLT card is 3 3/8" wide.
SLT backplanes are in a compartment, with space for up to 65 single width SLT cards plus some cables that use the same 2 x 12 connectors. Slots are labeled with columns A through N and rows numbered 2 to 7The IBM 1130 has two swing out gates each of which holds three compartments. The 1627 controller card from IBM (part number 5806223) fits into gate A, compartment C1, in slots M4 and M5.
The card implements logic to handle the input-output instructions for the device at Area Code 5, which is what IBM assigned to the 1627 Plotter. Asking the plotter to move the pen is done by issuing the XIO Write instruction, with bits in the transferred word assigned to lift the pen off the paper, lower the pen onto the paper, move the pen left or right or move the drum with the paper down or up.
The state of the Plotter is interrogated by issuing an XIO Sense Device instruction which returns a word with bits assigned for various conditions. The card will raise an interrupt request when the pen movement is complete, informing the software so that it can issue additional movement requests.
The card implements the XIO Write and XIO Sense Device functions for Area Code 5, requests the interrupt on level 3 when the operation is complete, and sends signals to the 1627 to command the various pen movements.
My redesigned card uses an FPGA board (Digilent CMOD S7) to implement the logic functions, with the card providing the interface chips for signals to and from the IBM 1130 and signals to the 1627 Plotter. It also drops the 12V power rail from the 1130 down to the 5V level needed for my chips and the FPGA board.
The most complicated part of the card is the contacts that form the connectors which plug into the SLT backplane. The backplane has 24 pins for each of the two sockets, while the card slides over the pins and locks into position. The locking is mechanically complicated and very difficult to reproduce, with the pins having a hook at the end that locks over a bent contact shaped to form a notch which holds the hook.
My previous version of the card had contacts that mate with the SLT backplane pins but don't latch. The card therefore backs out of the backplane sockets. I need to work out a method to hold the card down into the sockets until I want to pull it out.
SWITCHING TO USE PCBWAY WAS PAIN-FREE
I have been using other fabrication houses in the past but found the change extremely easy to make. I could use the same settings and design approaches with KiCAD that I used with other fab houses. The requirements for what has to be sent to PCBWAY.COM were very flexible and accommodated the settings I already used.
The website is easy to use (at least for anyone used to working with printed circuit fab houses), well documented, and has lots of supporting information if you have questions. I defined the size of my four layer printed circuit boards, accepted all of the default choices for copper weights, layer spacing and so forth, making only one change so that the order number is NOT printed on my boards. My design files were uploaded and the site gave me prices and other options.
It was very intuitive to request a standard manufacturing turnaround (4 to 5 days for my design) and select which shipping method I wanted. I picked DHL but there were other options including Fedex and UPS.
QUICK MANUFACTURING AND SHIPPING
They offer the ability to select faster manufacturing turnaround and even quicker delivery than the 3-7 days using DHL, but I found the standard choice and DHL to be good enough. I placed the order and once I coordinated the sponsorship with PCBWAY.COM they began manufacturing in the evening of Sunday March 15th.
The production was completed and the box went out with DHL by March 19th. The estimated time for standard production was 4 to 5 days, which this met with a bit of room to spare.
They don't control the shippers nor customs processing, but the box arrived on Tuesday March 24th. Quite satisfactory for an international shipment.
OPENING THE BOX
This came in a plain white box, shrink-wrapped and there was no rattling when the box was shaken. I opened the box to find some white foam padding inside.
I took out the padding and came to the receipt plus the circuit boards vacuum packed in a bubble wrap material. A bag of desiccant was sealed inside to absorb any moisture that might seep in. This is how printed circuit boards should be shipped.
There were actually six boards inside. My guess is that they had a panel with some errors in someone else's card and remade it, but the area with my board was good. The other person received five boards from six panels, so I got a bonus board.
I cut open the bubble wrap and inspected my boards. They look very well made, certainly matching my design and right up to the standard I expect from an excellent fab house.
As you can see, it is a relatively simple board, although I do use four layers to give me a solid ground plane. I feel confident that PCBWAY.com would handle far more complex boards and deliver the same quality. Thank you, PCBWAY.COM, for the sponsorship of this board for my project.
WILL ASSEMBLE PARTS ON THE BOARD SOMETIME LATER
This project is a lower priority activity which I will work on at times when I am in waiting mode on higher priority efforts such as having ordered additional parts. However, such pauses are frequent so I do expect to put the board together in a month or two. I did order the FPGA board and other parts already so that I could even install the components on it in short order. It will be the soldering of the SLT socket on the top that will take quite a bit more time and adjustment, so that may not be worked on until the priority bumps up.
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