Axon Axopatch 200B - Page 138

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HEADSTAGE TUNING PROCEDURE
Axopatch 200B, Copyright 1997-1999, Axon Instruments, Inc.
Gain and Offset Trim
These trims are optional if you are just trimming your present headstage and not changing
headstages.
Set CONFIG. on PATCH.
Connect the headstage to PATCH-1U model cell in the BATH position.
Carefully shield the headstage and model cell with foil. Ground foil to brass pin on
headstage using suitable jumper.
Select I on FRONT PANEL METER.
Use JUNCTION NULL to zero the current.
Set HOLDING COMMAND to 100 mV (toggle set to x1).
Switch HOLDING COMMAND between + and -.

Trim RT4 so that the difference on the meter is 20 nA (nominally ±10 nA if the
current has been exactly zeroed).
Repeat procedure with CONFIG. set to WHOLE CELL β = 1 and trim RT5.
Repeat procedure with CONFIG. set to WHOLE CELL β = 0.1 and trim RT33.
Remove PATCH-1U model cell.
Use appropriate trim pots on back panel to zero the meter for both PATCH and WHOLE
CELL CONFIG.
Set CONFIG. to WHOLE CELL β = 1.
Set HOLDING COMMAND to 200 mV.
Switch HOLDING COMMAND between + and - .

Trim RT14 until meter reads zero for both polarities.