ELECTRONICS
Replacing the OP-Amp Chip in Your SRI GC
Thepartskit in theplastic tackleboxunder thered lidofyourSRIGCcontainsaspareOP80orLF356
amplifierchip. AdditionalOP-AmpchipsareavailableunderSRIpartnumber8690-7000. FID,NPD,HID,
TID, PID, FPD, andDELCDdetectors use theOP-Amp chip. TheOP-Amp chip amplifies the analog
detectorsignal. Youshouldreplaceadetector’sOP-Ampchipwhenyou’renotgetting thesignal response
thatisotherwiseconsistentlyobservedfromyourdetector,whenthedetectorsignalispeggedup(5000mV)or
down (0),orwhen thedetectorhas failed theWetFinger test.
Testing theOP80orLF356AmplifierChip(s)
WetFingerTest:
1. Makea“V”signwith thefirst2fingersofyourhand.
2. Moisten thosefingers(lick them).
3. Placeone fingeron thecollectorelectrode, andsimultaneouslyplace theotheronbaremetal, like the
columnoven lid. Makeyourcontactbrief,andobserve themilliVoltreading.
4. Thedatasystemsignal should jump from0 to5000mV (maxvoltage), andcomebackdownwhenyou
removeyourfingers. Ifyourcontactdoesnotproduceasimilarlysignificantchange in themilliVoltreading,
thenyoushouldreplace theOP-Ampchip.
Ifyourdetectorsignal ispeggedupordown, try thefollowing:
1. TurnOFF theGCpower (forat least10seconds).
2. Shutdown thePeakSimplesoftwareprogram.
3. Re-launchPeakSimple.
4. Turn theGCpowerON.
5. Withoutzeroing thedatasystemsignal,observe themilliVoltreading. If it isstillpeggedat5000mV,
replace theOP-Ampchip. Sometimes thesignalwillbepeggedatornear0,but5000mV ismuchmore
commonwithafaultyOP-Ampchip.
TSETNIAGROTCETED
)S(ROTCETED
DAOLYMMUD
SGNIDAER)S(NIAGTEGRAT
DIT/DIH/DPN/DIF
CNBforetnecotdetcennocrotsisermhOM00061
dnuorgdnakcaj
TLIFIH,)Vm001(DEM,)Vm0002+(HGIH
)Vm0002+(
DIP
CNBforetnecotdetcennocrotsisermhOM00061
dnuorgdnakcaj
WOL,)Vm001(DEM,)Vm0001+(HGIH
)Vm01(
DPF
CNBforetnecotdetcennocrotsisermhOM00061
dnuorgdnakcaj
TLIFIH,)Vm001(DEM,)Vm0001+(HGIH
)Vm0001+(
DCLED
eriwetihw&derotdetcennocrotsisermhOM001
slanimretwercs
WOL,)Vm041(DEM,)Vm0041+(HGIH
)Vm41(
Ifyouhavedummy loadsor themeans tocreate thematyourdisposal,youmayuse themethodoutlined
in the tablebelow to test theOP-Ampchip(s). If the readingsarenotwithin the target range,youshould
replace theOP-Ampchip(s).
TheOP80AmpChip
