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


Open questions:

  • Summary: no plasma. How to get something?
  • Are fuses good?
    • top
      • BUS AGC 4A
      • Ok
      • Removed and tried to power up
      • Everything seemed to work fine. Hmm..
    • bottom
      • 250V 20A
      • Ok
      • I can't imagine that is the correct fuse
  • Where is proper place to attach RF ground strap?
    • Currently on lid hinge bolt
  • What is a good test pressure? (air)
  • Why doesn't pressure gauge work?
    • Preliminary troubleshooting indicates instrument (the DMM side) is fine
    • ie the sensor is outputting negative voltage and is only supposed to output 0-10V
    • Maybe it was modified?
  • Can I verify RF out using scope or something?


  • Installed missing relay per model found in Markus system
    • Potter & Brumfield CUB-51-70120 Time Delay Relay 1-120 Sec 10A 120VAC
  • Temperature controller isn't hooked up. Ignore
  • Timer: I presume this is for auto mode and am ignoring for now
    • Cannot if RELAY LOW
      • Around 5 Torr
    • Can if RELAY HI
      • Around 4 Torr
    • Can if both
    • Initially makes loud hum, but quiets down after being on for 30 seconds or so
  • POWER ADJUST / display
    • Glitches to some values at startup
    • Otherwise steady 0
  • Why aren't back panel outlets working?
    • I thought they did before?
    • This might be fine: think pressure was too high to show reading
    • Confirmed
  • AUTO
    • After leaving on for a while a neon light turned on the timer
  • Not able to get any voltage across the large blue cap
    • This looks like an important power source for the RF plasma circuit
  • Front relay is triggered by AUTO
    • Controls relay near EMI filter
    • Relay far side goes to top fuse
    • Other side to large blue cap
    • Looks like cap is fed from full wave rectifier, probably always stays charged. When relay is flipped on it supplies HV to the board at right
    • Upper left relay turns on at power on and feeds the full wave rectifier
  • Rectifier
    • - bottom blue
      • Connected to cap -
    • + top brown
      • Connected to PCB (not cap...)
      • PCB might actually gate charging
    • Take off output terms and see if HV present
      • DMM: 116.7 VDC
      • Seems plausible
    • Some of these caps look kind of gnarly
      • Isn't there an infamous exploding Rifa cap or something like that?
  • Front power supply
    • OLV15-15
    • 15.4V out
    • Think I saw a bit less initially (maybe 10V) then heard a relay click and it went up
  • HV out internal to case
    • No shield...spark plug wire or something like that
  • Board
    • 7805
      • 15.4 V in
      • 5.05V out
    • 7915
      • -15V out
    • Orange cap
      • 15V
    • Far side connectors to 'HI VOLTAGE" heatsink
      • A lot of them have -78VDC referenced to ground
      • Looks like its a push pull circuit for the transformer
      • Think there are more transistors underneath
      • Cap is also about -78V to ground, so this may just be an artifact of how grounding is done
    • Optoisolator
      • Guessing it triggers switching
    • Think the NTE5552 is gating HV
      • NTE5552 - Thyristor, 200 V, 40 mA, 16 A, 25 A, TO-220, 3 Pins
        • "The NTE5550 thru NTE5558 SCR’s are designed primarily for half−wave AC control applications,"
        • Which is exactly what we are feeding it
        • Gate is at far side of board. What does it connect to?
      • Ground ref to cap -
      • Yellow wire should get HV to go to fuse center and then supply HV to cap + (via outbound orange wire)
      • Brown wire between board power transistors has 170V
      • Orange wire next to it is return from large blue HV cap / relay
        • Getting HV here would be important
      • NTE5552 middle has +170V
      • sides are near 0V
      • Think the yellow 1:1 transformer is an isolation transformer to pulse the gate drive and turn the SCR on
      • Maybe I should start using scope instead of DMM