Rescue 1130: 2014 Pickup of an IBM 1130 System and More

Adding functionality to 1627 Plotter controller card project

Working on the connectors for the substitute 1627 plotter controller card

1130 MRAM board effort continues - not quite there yet

Continued confusion over analog issue with the 1130 MRAM board BUT progress made

Collecting data with logic analyzer on 1130 MRAM parity stops - tantalizing hints

Finishing the build of the substitute controller card to hook a 1627 plotter to an IBM 1130

Chasing down 1130 MRAM memory issues

Odd error detected with memory, possible issue on the 1130 MRAM board

Trying to track down the parity stop failure using my 1130 MRAM board while running IBM's core memory diagnostics

More work building 1627 plotter controller card for IBM 1130

Constructing the 1627 plotter controller card for the IBM 1130

Honing the FPGA logic for the 1130 MRAM board and testing results

Finding remaining issues on my MRAM board

1627 Plotter controller card redesign - printed circuit board arrives from PCBWAY.COM

The advantage of leveraging FPGA for 1130 related designs - 1627 Plotter behavior discovery

Hoping to finish the testing of the 1130 MRAM core memory replacement board

Testing the 1130 MRAM board on the IBM 1130

Finished construction of the new 1130 MRAM board, part 3

Constructing the new 1130 MRAM board, part 2

Constructing the new 1130 MRAM board today, part 1

Redesigned 1627 Plotter controller card while waiting for my MRAM board and parts

1130 MRAM testing observations while I wait for the new board for the updated design

Looking at 6V regulator SMS card to resolve 1130 power issues - part 3

Watched pot syndrome - can't get the 1130 6V power regulator to trip now that it is instrumented

New rotate and tilt tapes for the 1053 typewriter of the System Source Museum's 1130

Code written and simulated for FPGA in new 1130 MRAM core memory replacement design

Testing 1130 MRAM board - defect in design identified

Slowly improving ability to use LTspice to model circuits with germanium components

Replacing parts on 6V regulator SMS card to resolve 1130 power issues - part 2

Replacing parts on 6V regulator SMS card to resolve 1130 power issues - part 1

Deconstructing the +6V regulator SMS card schematic to isolate functions

Further dive into the 6V regulator circuit breaker spurious tripping

Ordered new components for 6V regulator SMS card for IBM 1130

Dealing with power supply breaker trips in IBM 1130 6V regulator

Testing fully assembled new 1130 MRAM board - read retriggering solved!

Testing attempt on new 1130MRAM board

Interim method won't work; assembling new PCB

Attempting to test the discrete transistor method of resolving the 1130 MRAM retriggering

Ordered new PCB with my original fab to reduce delays

Revised design and producing a new board for 1130 MRAM project

Checking out the low ESR cause for the 1130 MRAM ringing

Oscillation in LD1117 voltage regulator appears to be the root cause

Same problem with 1130 MRAM in spite of new board

Beginning testing of new PCB for 1130 MRAM board

Replacing some chips on 1130MRAM board based on testing

Finishing new PCB for 1130 MRAM, waiting on memory chip

Building new version of the PCB for 1130 MRAM

More work on retriggering issue with 1130MRAM

1130 MRAM - quick check after removing large buffer capacitors

1130MRAM smoking gun found

1130MRAM spurious retrigger - what it can not be then musings

Output of Schmidt Trigger after a bit more massaging

Investigations for 1130 MRAM board - ways to block retriggering of the timer chip

Continued testing of 1130 MRAM board - results of probed points and added power wires

Continued testing of 1130 MRAM board - more probes added to zoom in on problem area causing retriggering

Continued testing 1130MRAM board - retrigger problem continues to bedevil me

Retrigger of 1130MRAM likely due to slight wobble on trigger signal

Side project - MV864A meter restoration - converting manual calibration/test instructions to the version I own

Continued testing 1130MRAM board - retrigger redux

Continued testing 1130 MRAM board - working on the retriggering

Continued testing 1130 MRAM board - dealing with the signal bounce and retriggering

Side project - MV864A meter restoration - almost complete schematic produced

Continuing testing of the 1130 MRAM board

Side project - MV864a meter restoration - simulations and look at the non-board wiring

IBM 1130 MRAM memory board - root cause of the unwanted stream of pulses from the board being corrected

IBM 1130 MRAM memory replacement - investigating Parity Check and random data occurrences

IBM 1130 MRAM memory replacement - continuity test, then testing on the IBM 1130

Side project - MV864A meter restoration - blocking out entire schematic

Side project - MV864A meter restoration - simulating the DC Modulator Driver that produces 94Hz chopper signal

Construction of new 1130 MRAM memory board completed

PCBs and parts are on hand - beginning construction of new 1130MRAM board

Side project - MV864A restoration - substantial progress in reverse engineering

Side project - MV864A restoration - reverse engineering power supply section

Side project - MV864A restoration - reverse engineering challenge

Testing the 1130 MRAM core memory replacement on the IBM 1130 system - part 4

Testing the 1130 MRAM core memory replacement on the IBM 1130 system - part 3

Testing the 1130 MRAM core memory replacement on the IBM 1130 system - part 2

Testing the 1130 MRAM core memory replacement on the IBM 1130 system - part 1

side project - IBM 3278 terminal restoration - planning for keyboard substitution

Side project - IBM 3278 terminal restoration - looking into the high voltage power supply

Success with the bench testing of the 1130 MRAM memory board finally

side project - restoration of IBM 3278 terminal - some debugging

side project - restoration of IBM 3278 terminal - inspect, mechanical fixes, first power on

More work on bench testing for the 1130 MRAM core memory board

Using LT SPICE to study back feed voltages from digital inputs when power supply not operating

Side project - restoration of IBM 3278 terminal - shipment arrives

Bench testing of the 1130 MRAM core memory board still not successful

Restoring IBM 2501 card reader - more focus on the stacker side of the mechanism

1130 MRAM board - failed chips identified and replaced

Restoring 2501 reader - linear bearing repair, still one roller bearing to resolve

Restoration work on 2501 card reader - card path and stacker

Side project foiled - restoration of an IBM 3278 terminal

Side project - restoration of Sony VP-5000 U-Matic tape deck for Space Force Museum

Side project - restoration work on Millivac MV-864A meter, part 3

Side project - restoration work on Millivac MV-864A meter, part 2

More Bench Testing of the 1130 MRAM memory board

Bench testing strange power supply behavior testing MRAM board - followup

Continued testing of the 1130 MRAM Core Memory Replacement board

Restoration of top cover glass for IBM 1132 printer