Top Of Enclosure Remove And Replace Procedure; Eprom And Novram Replacement - Lakeshore 340 User Manual

11.6 TOP OF ENCLOSURE REMOVE AND REPLACE PROCEDURE

WARNING: To avoid potentially lethal shocks, turn off controller and disconnect it from AC power line
before performing this procedure. Only qualified personnel should perform this procedure.
REMOVAL
1. Set power switch to Off (O) and disconnect power cord from rear of unit.
2. If attached, remove 19-inch rack mounting brackets.
3. Use a Phillips screwdriver to remove two flat-head screws from center rear top and bottom of enclosure.
4. Use 5/64 hex key to remove four screws attaching top panel to unit.
5. Use 5/64 hex key to loosen four screws attaching bottom panel to unit.
6. Carefully remove the back bezel by sliding it straight back away from the unit.
7. Slide the top panel back and remove it from the unit.
INSTALLATION
1. Slide the top panel forward in the track provided on each side of the unit.
2. Carefully replace the back bezel by sliding it straight into the unit.
3. Use a Phillips screwdriver to install two flat-head screws from center rear top and bottom of enclosure.
4. Use 5/64 hex key to install four screws attaching top panel to unit.
5. Use 5/64 hex key to tighten four screws attaching bottom panel to unit.
6. If required, reattach 19-inch rack mounting brackets.
7. Connect power cord to rear of unit and set power switch to On (l).

11.7 EPROM AND NOVRAM REPLACEMENT

Part of the operating software for the Model 340 is contained on one Erasable Programmable Read Only
Memory (EPROM) Integrated Circuit (IC). The reference designator for the EPROM is U146. See
Figure 11-11. The EPROM will have a sticker on top with the label SV.HEX and the date. A Non-Volatile Ram
Access Memory (NOVRAM) IC (U28) is also included in the Model 340. Please use the following procedure to
replace either the EPROM or the NOVRAM.
CAUTION: The EPROM and NOVRAM are Electrostatic Discharge Sensitive (ESDS) devices. Shock-
proof wrist straps (resistor limited to <5 mA) must be worn to prevent injury to service
personnel and to avoid inducing an Electrostatic Discharge (ESD) into the device.
1. Follow the top of enclosure REMOVAL procedure in Paragraph 11.6.
2. Locate EPROM U146 (M340SV.HEX) or NOVRAM (U28) on the main circuit board. Note orientation of
existing IC. See Figure 11-11.
3. Use IC puller to remove existing EPROM/NOVRAM from socket.
4. Noting orientation of new EPROM/NOVRAM, use an IC insertion tool to place new device into socket.
Match notch on
EPROM to notch
in socket
1
Typical EPROM
5. Follow the top of enclosure INSTALLATION procedure in Paragraph 11.6.
Service
Lake Shore Model 340 Temperature Controller User's Manual
M340SV.HEX
08 06 96
01.01.01
Match notch on
NOVRAM to
notch in socket 1
Typical NOVRAM
DALLAS
xxxxxxxxx
xxxxxxxxx
11-7