Soemtron 222 Downloads, S#74005

S#74005 - Technical Description

Soemtron logo of unknown origin

This page has downloadable drawings and information for our Soemtron ETR222 electronic calculator serial number 74005.  Updates and corrections to the drawings will be uploaded on an ad-hoc basis as it comes to hand, but we do not accept responsibility for their subsequent use.  The files will usually be in pdf format so a current copy of an Adobe Acrobat[1] reader will be needed.  To download the files right click the relevant link and select "file save as ....".  All files on this website are ©2007- www.soemtron.org and its group websites[2] or the files respective owner.

Soemtron logo

If you have any further historical information, circuits, drawings, photographs, data or manuals about the Soemtron ETR220, 221, 222 and 224 or their manufacture, test equipment (Prüfgeräte) or you just know more about the Soemtron companies in general then please let us know, contact us.

September 2017 - Reverse engineering our Soemtron 222 has just started and initial results have confirmed that the 222 is in fact derived from the ETR224, not the ETR220 as we thought some while ago.  Several of the main PCB's are labelled "224–" (the "4" is scratched out) and several "22  –", with several being at the same issue level as the corresponding PCB of the ETR224 board.<


Part number list - a list of all Soemtron part numbers currently available to us from various documents (35Kb)

3D CAD -
All 3D CAD files have been created using the latest version of IronCAD 3D design software[3].  The files are supplied in native (.ics) and Step (AP214) formats within a zipped file.  They can be viewed with a copy of IronCAD Compose[4]

Daro 11 pin connectors - models for the Daro 11 pin plug and socket connectors. (1.9Mb)
Daro 20 pin connectors - models for the Daro 20 pin plug and socket connectors. (2.5Mb)
Daro 32 pin connectors - models for the Daro 32 pin plug and socket connectors. (2.8Mb)
Test connector shorting link - V7 test connector shorting link for normal operation. (184Kb)

Soemtron 222 Circuit and Logic diagrams –

(See the "Snagging list" file for the current list of things to check with our ETR222)
ETR222 Electronics cage - 3D model files, pdf view. (5.7Mb)
ETR222 Keyboard assembly - 3D model files, pdf view. (43Mb)

Soemtron ETR222 Circuit and Logic diagrams –

(See the "Snagging list" file for the current list of things to check with our ETR222)
Power supply circuit updated 24/03/2021
Keyboard circuit
logic
updated
updated
24/03/2021
24/03/2021
Display circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 1 - Core store, read amplifiers and digit drives 2-4 circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 2 - Core memory drivers and decoding circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 3 - B1-4, VOR and Unknown function latches circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 4 - 5 bit address "Z" counter circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 5 - 25Khz clock, R, F6, undetermined functions, 14 drive signals circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 6 - Wheel position, M latch, undetermined function, various gating circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 7 - B1-4, Arithmetic unit A Register, digit drives 5-9 circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 8 - F1/3, Arithmetic unit E Register, Carry latch and digit drives 0/1 circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 9 - READ/WRITE, S1, V, miscellaneous gating circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 10 - MZ, miscellaneous gating circuit circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 11 - UBER, F2, VER, DOUBLE, and minor gating circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 12 - F1, F3, F4 and F5 circuit
logic
updated
updated
24/03/2021
24/03/2021
Board 13 (under keyboard) - Display drivers, MINZ, SPE, keyboard debounce circuit
logic
updated
updated
24/03/2021
24/03/2021
Backplane circuit updated 24/03/2021
Block diagram block updated 24/03/2021

All current circuits for the Soemtron ETR222 (8.8Mb file) circuit updated 24/3/2021
All current logic diagrams for the Soemtron ETR222 (3.2Mb file) logic updated 24/03/2021
Current problems with the circuits for the Soemtron ETR222 snag list updated 24/03/2021

1 Download Adobe Acrobat Adobe reader download.[top]
2 Group websites www.soemtron.org
www.soemtron.com
www.soemtron.eu
www.pdp-7.org
www.pdp-7a.org[back] [top]
3 IronCAD IronCAD download.[back] [top]
4 IronCAD Compose Compose download.[back] [top]

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