Technics PE II

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A popular unit. A number of people have this or similar including:

  • John McMaster
  • Markus
  • Sam Z


  • Parallel plate 15" chamber
  • Microprocessor controller
  • 11" electrode
  • Power?
  • 500 Watt @ 30Khz
    • Other source says 300W @ 13.56 MHz
  • Three gas system
  • Wafers
    • 4 4"
    • One 5-8"
  • Weight
    • System: 120 lb
    • Module: 30 lb
    • Pump (which?): 100 lb


  • MKS PDR-C-1A Baratron pressure gauge
    • Original had an on/off switch, new one does not
    • Doesn't really matter since I always want this on if master power is on
    • Had to be replaced, but kept the original display since its part of the Technics chassis, not the Baratron chassis
    • Official cable is CB473-1, although I just used random wire I had laying around. IIRC the original (damaged) cable had shielding
  • MKS Baratron 222 AHS
    • Blue
    • Compression fitting
    • Range: 10 Torr
  • TODO: temp controller
  • TODO: timer
  • Filters: HOKE 316SS Filter Element, 2-5 microns, No. 2231
  • Solenoid: Skinner Electric Valves, black w/ blue logo w/ yellow circle
    • Originally were 2 bore. Missing vent valve, replaced w/ similar 3 bore and plugged top
    • 8-32 screws
    • 120V
  • Solenoid bundle connector (solenoid side)
    • Blue Amphenol 7 pin
    • Amphenol 126-198 Miniature Hex Connector Thermoplastic, Solder Cup Terminal
    • Related: EML 7 Pin Extension Cable M7S/ M7P Amphenol 126 Series Compatible! 15ft/ 4.5m
    • Mates to: 7 Pin Male Miniature Hexagonal Panel Connector Plug Lock Hood Cable Clamp 126
    • Related: Reclaimed AMPHENOL 126-192 7 pin Female Socket! 126 Series/ WPI
      • Doesn't have lock
    • 126-198 - Circular Connector, BCE Key, 126 Series, Panel Mount Receptacle, 7 Contacts, Steel Body


  • Pins AD
    • Gas 1
    • 358 ohm
  • Pins CF
    • Vent
    • 355 ohm
    • Tested via female fencepost connectors soldered to AC cord

Pressure gauge

  • Blank at atmosphere
  • Proper set points?
  • Couldn't find 222A manual, but found 122A
    • Shielded cable assemblies, in a nominal 10' (3M) length, with one end terminated in “flying leads” (pigtail) fashion are available at nominal cost. Shielded cable assemblies are recommended, especially if the transducer's environment contains high EMI/RFI noise.
    • Standard wire colors (which I didn't follow). Not sure if its worth the effort to recable though
    • Theory: 0-10V out, noting this unit is 10 Torr range. ie 1000 mV on display => 1 Torr. However, I'm still seeing negative DMM value. But it is tracking voltage, so ?


Pressure gauge:

  • PS/DVM
  • PDR-C-1A



  • Came with bad pressure gauge
    • Tried to order replacement but seller sent wrong part
    • Second replacement installed
    • Think it worked? Needs to be checked out
  • Pressure gauge was likely bypassed
  • Missing manifold valve
    • Replacement ordered but not installed



  • Clear area around it
    • Put Ron back up
  • Order lazy susan
  • Vacuum gauge controller is bad
    • Modified and in bad state: repairs may be difficult
    • Looking to source identical replacement or something new entirely

Vacuum gauge

  • Rewired with colored wires + better connections
  • Still reading bad
    • Negative reading (switch center)
    • Low setpoint can be set (switch left)
    • High setpoint can not be set (switch right). Shows same negative value as center
  • Opened gauge
    • Loose/missing cover screws
    • Several wires have been desoldered
    • Diode is hanging loose
    • Bad state. Probably not worth further troubleshooting
    • Try to source replacement identical module, or find another gauge with low/high set points



  • Hooked up vacuum solenoid manifold after fixing chassis connector. Works! (all three valves)
  • Pressure gauge still weird
  • TODO: install valve to allow isolating chamber and check for leaks
  • TODO: install pressure gauge to provide known reference



  • Re-grease main o-ring
  • Smooth out scratch on main o-ring seating



  • Re-grease viewport o-ring
  • Still holding at around 200-300 mTorr
    • Note: pump just on gauge w/ chamber valve shut < 100 mTorr
  • Put KF25 blank on chamber vacuum port => still 200 mTorr
    • Implies there is a leak in the area around chamber valve and the chamber, a very small area to triage
    • Repeated observations that moving the chamber valve effects pressure level
  • Next: disassemble chamber valve
  • Chamber valve
    • Valve gasket destroyed. Removed
    • But external gasket is fine. Clenaed
    • Lots of debris (including ICs from previous owner...)
  • Pressure significantly down (120 mTorr IIRC), but 1E-3/sec leak present
  • Acetone tests confirm its in the valve bellows section roughly
    • Where? Could narrow down, but unclear if that would help
  • Tried to replace the valve w/ improvised blanks, but nothing worked well
    • Putty: collapsed under vacuum. could support better but meh
    • Aluminum: only lasted a few minutes before popping
    • Mylar: leaking
  • Fabricate a blank to replace it