IBM 360 Supplemental Control Panel

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IBM 360 Supplemental Control Panel	by Bill Degnan - 05/27/2010 13:07
An unidentified 1800, dated 1969. Click Image for larger view. detailed pictures This is an IBM 1800 supplemental control panel I picked up on Ebay a few weeks ago. The service tag is 1969. It's full of SLT chips. My theory is that it may have been used to monitor data transfers or to make sure one machine was cabled up correctly to another, I don't really know. There were computer-like devices that used the CPU of the mainframe computer to test and manipulate the mainframe's data as an add-on function for diagnostics and repair purposes. This type of device contributed to the evolution of stand-alone microcomputers, the Altair was not simply a simplified PDP 8. Add a microprocessor and RAM to a device like this and you have a microcomputer. I cleared out the foam that lined the rear inside cover, it was disintegrating and eventually would have ruined the unit. I tried to find a way to cover it up, but it was too far gone. I have to clean all of that sticky dust off the components. You'll notice in some of the hi-res shots that there are little brown dots, that's the foam. Reply
IBM 360 Supplemental Control Panel	by Bill Degnan - 05/29/2010 13:06
The front panel has two rows of 18 DISPLAY lights but the IBM 1800's used a 16-bit register display so I am not sure if the lights correspond with memory. The first row is labeled A - DISPLAY, the second B - DISPLAY. The 18 toggle switches under the 2 rows of lights are "three way switches; ON / NULL / OFF. Click image for larger view. Below the two sets of 18 DISPLAY lights on the left side is another set of 10 lights and toggle switches labeled C - DISPLAY. Click image for larger view. To the right of the C - DISPLAY controls is a pair of black strips which I had hoped was used for some kind of numeric readout, but upon closer inspection I learned that it's just paint. The two lights are labeled SAMPLE INTLK and DISPLAY HOLD. Click image for larger view. The bottom right of the control panel is used for various control switches including a section for display SET CONTROL, HOLD CONTROL, and RESET. There is also a PROBE INPUT and a COMPARE EXIT jack. Click image for larger view. On the bottom right the controls pertain to SIGNAL LINES TO DEVICE ADAPTERS. Click image for larger view. Removing the rear cover reveals a set of Solid Logic Technology (SLT) chips and a few connectors. Click image for larger view. Here is a close up of the SLT chips installed in the back-plane. SLT / flip chips were common during the 60's and most computers used some sort of flip chip set. A few have been removed to reveal the connector pins. Click image for larger view. A close up of an IBM Solid Logic Technology (SLT) controller. Click image for larger view. IBM Machine History initiated when the item went into service in October 1969. Agh! data and power cables cut! Reply