Technics PE II

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

Specifications:

https://www.chiphistory.org/274-technics-pe-ii-a-planar-etcher

Components:

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

Solenoids

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 ?

McMaster

Pressure gauge:

Summary:

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

Summary:

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

Summary:

Summary:

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