Siemens Polyphos 30, XRAY Inverter and Control Panel Teardown (Part 3 of 3)

[@Jegbonto]

Great video as always. The computer section is most probably a form of finite state machine. Simple and robust logic control using the "states" preprogrammed into the eproms, directly accessed with the address bus.

[@KaizerPowerElectronicsDk]

Thank you for that explanation :)

[@SeanBZA]

@@KaizerPowerElectronicsDk Computer would likely be in the form of a state machine implemented in the boards, with the ROMs holding a series of instructions along with performing the more convoluted logic, with the other boards acting as different parts, like a board acting as some registers, another acting as accumulator and ALU, so that a simple loop through a counter runs all tasks in sequence, with branching decisions being implemented in the hardware. Worked on similar things, that used serial memory, comprised of some serial CCD delay lines that were main memory, looping around with a clock to bring out each block of data out to be acted on in sequence. Mostek MK4007 memories ( not easy to find data on these 1970's vintage units any more, not helped by the much more common part being a CMOS array) as main store, and then all TTL to implement the ALU, multiplier and with a few ADC converters and DAC units on cards, and then serial data lines to peripherals bringing data in and out, with a load of options programmable in the firmware by assorted means. Largest pin count, aside from a dozen 2708 EPROMS, were some Intersil analogue switches, used for switching analogue inputs and outputs, and also used as synchronous rectifiers as well for AC inputs. Worked well and was reliable, with very little chances of bugs in the hardwired logic, as literally every cycle of the main loop was running test sequences that would hard fail the unit till power cycle if anything stopped, along with another hardware watchdog that did the same. Did find the one unique fault that did not do this properly, where a power supply fault applied unregulated input to the 5V supply rail, and the built in overvoltage crowbar had silently failed, so the entire board ran for a long while with the 5V rail being at around 14V. Only failure was a 5407 hex buffer, which is ironically rated for 30v on the output. It melted it's lid off as it failed. Power supply rebuilt down to the resistors, and new board installed, and away it went again, passing the notoriously fickle ATE machinery as well. That was a room of racks, dominated by a massive crossbar switch array, driven by a HP mini in the bottom of one rack, that was bootstrapped with switches, to get the tape bootloader to run, to run the ATE program, and used a glass TTY, with special addons to operate the ATE.

[@ZidanMedtech]

Siemens is the best x-ray unit in our world, this old unit is using the High-Frequency technique that built on reducing the number of turns in HT transformer to a minimum volume that the x-ray tube is collected in a compacted HT tank. This HF technique is still in use by most x-ray new units

[@RichardTomkins]

The power module with the small plate blocking it is not plugged into a backplane that has connectors that would retain it in place, thus, it needs mechanical retention.

[@natebender4740]

Just subscribed! I just recently got into X-ray research and your teardown was awesome to watch. Great videos.

[@ElectroXa]

I would love having this X ray machine to tear down :-) 😉 you made a good video, as always 👍👍

[@KaizerPowerElectronicsDk]

Thank you :)

[@johnneybot9542]

Dave Jones ( that crazy aussie guy ) would say that unit is "sex on a stick"

[@KaizerPowerElectronicsDk]

Kink comes in all different packages!

[@RichardTomkins]

There was an 8 bit CPU on the module with PROMs.

[@Lovreli]

i absolutely love your videos! im just wondering what the hell kind of scrapyard do you go to the one close to me has an electronics section but it rarely has any parts that are actually usefull

[@KaizerPowerElectronicsDk]

Public / state-driven scrap yards are worthless, only consumer products and laws forbid you to take anything away, at least in Denmark since the EU laws for producers being responsible for the discarding of their own products went in effect. You need to find privately owned scrap metal dealers, precious metal scrappers and such, they get all the interesting stuff from the industry :)

[@Lovreli]

@@KaizerPowerElectronicsDk the one i go to allows me to take stuff. That one is the only one in my area so i have to other options

[@ElecDashTronDotOrg]

Did you get this thing for free from a scrap yard?

[@KaizerPowerElectronicsDk]

Almost, paid for 250kg Iron :)

[@SeanBZA]

@@KaizerPowerElectronicsDk You will get that back plus having sorted out the copper and aluminium from it. My scrapyard charges from 30c Euro per kilo for stuff, though often he will just give electronic parts for free as the work in scrapping them is too hard. Did get an inkjet printer free, going to strip down a continuous jet printer soon to see how one works, even though this unit actually does still work, just was a trade in on new. Pumps, valves and such, along with a lot of PTFE piping joining the lot, as the solvent is MEK, which dissolves pretty much all other plastics, aside from pure PTFE and some types of HDPE. For now just filled the tank enough to start it using alcohol, as it is also a solvent used when you use the edible inks these printers can also use.

[@Basement-Science]

Beautiful machine! Maybe remove all the fuses and try adding them all back one after the other. Get at least some parts running.

[@KaizerPowerElectronicsDk]

In retrospect that would have been a good idea to try that, but as you have properly seen, it is in bits and pieces now :)

[@RichardTomkins]

Typical 70s to 80s circuitry. The Therac issue was completely different to an xray system.