Beefchicken Industries

Sundry Switching Stuff

Interalia MMU-2 Manuals

Thanks to John Novack for these.

Interalia MMU-2 Manual
Interalia MMU-2A Manual

Idiot's Guide to breaking & Fixing the Sage 930A

Work In Progress

The Sage 930A is a handy piece of test equipment, which can be had for a fairly reasonable price on eBay. Being an 80's vintage piece of electronics, it is also very repairable, so even units being sold as non-working can be quite easily brought back to life. From a design standpoint, it was quite leading edge, containing two break-through devices: the first DSP (the TI TMS320) and the first FPGA (the Xilinx XC2064).

Sage 930A Hardware Breakdown

CPU Board

The supervisor brains of the system; a 4 MHz Z80 CPU and supporting logic.

Daughter Board
  • Intersil ICM7170 Real-Time Clock
  • AMD Zilog Z8530 SCC
  • Lithium Iodide Battery
Main Board
  • Z80 CPU, 4 MHz
  • Z80 CTC
  • 7 ROM
  • 1 6264 RAM (64 kbit, 8 kbyte)
  • Lithium Iodide Battery
  • clock (mhz?)
PCM ESF Board (two in system)

There are two identical PCM cards in the system, the only difference between them being a jumper setting and their position in the chassis. The ROMs on these cards are part of the system address bus, and the set will fail its boot-up ROM tests if either of the PCM cards are removed.

  • Z180 CPU, 6 MHz - integrated clock generator, 16-bit counters/timers, interrupt controller, wait-state generators, serial ports and a DMA controller.
  • Xilink XC2064 - 64 cell FPGA, Xilink's first FPGA
  • ROM
  • 6264 64 kbit ram (8 kbyte)
  • 1 rom
  • SCC
  • Xilink XC2018 - 100 cell FPGA, confusingly numbered sibling to XC0264
  • Analog Devices ADC0808 - 8 bit ADC with 8 channel MUX
  • LF147/LF347 Wide Bandwidth Quad JFET Input Operational Amplifiers
  • National LM319 High Speed Dual Comparator
  • Pulse transformers - T1 in and out
  • Crystal Semi CS61534 - PCM Transceiver
  • Crystal Semi CS2180A - T1 Transceiver
DSP Board

Handles signal processing and tone generation functions.

  • Burr Brown PCM53 - 16 bit audio DAC
  • DG212CJ - Quad SPST CMOS Analog Switches
  • DG211 - Quad SPST CMOS Analog Switches
  • LF356N - JFET Input Operational Amplifiers
  • LF353N - Dual JFETInput Operational Amplifier
  • LF347N - Wide Bandwidth Quad JFET Input Operational Amplifiers
  • National LM161N - High Speed Differential Comparators
  • DAC08C - 8-Bit high-speed multiplying D/A converter
  • 6264 RAM (64 kbit, 8 kbyte)
  • 74HC193 Presettable synchronous 4-bit binary up/down counter
  • 6116 - 16kbit, 2kbyte SRAM
  • TI TMS32010 - DSP
DC Board

In addition to the listed semiconductors, this board contains a number of relays and transformers, providing all the facilities required to simulate and terminate an analogue line interface.

  • Analog Devices ADC0808 - 8 bit ADC with 8 channel MUX
  • Motorola MC14569 - Programmable Divide-By-N Dual 4-Bit Binary/BCD Down Counter
  • LM324 - Low-Power, Quad-Operational Amplifiers
  • DP8311 - Octal Latched Peripheral Drivers (100 mA driver)
  • Motorola MC145436P - Low Power Dual Tone Multiple Frequency Receiver
  • TL074CN - Low-Noise JFET-Input Operational Amplifiers
  • CD4052B - 2-Channel, 4:1 Analog Switch with Low ON-Leakage Current
  • TL072CN - Low-Noise JFET-Input Operational Amplifiers
  • NE571 - compandor
  • DG212CJ - Quad SPST CMOS Analog Switches
Display Board

Not documented yet. Largely dominated by VFD driver circuitry.

Backplane Board

Not documented yet. Very little active electronics.

Power Supply

In both of my Sage 930As, the power supply is a custom Power-One unit. It appears to be a fairly standard +5v, +15v and -15v design, tweaked (by Power-One) to provide -52V, -48V and an opto-isolated 120Hz powerline-derived timing reference signal. The circuitry providing the -48V regulation and the 120Hz timing signal appears somewhat bodged on to the end of a standard power supply design. The diodes constituting the bridge rectifier for the timing signal are tucked in wherever there is free space on the PCB.

This power supply has a number of what appear to be custom semiconductors. Depending on the vintage there can be up to three: the main regulator IC, the main chopper transistor, and the feedback transistor. The desire to obscure the origins of the regulator IC seems to have abated in later power supplies, so I know that it is a LM723 regulator. The other two devices continue to have untraceable part numbers.

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