TTI TF930 Service Manual - User Manual

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TF930 & TF960

3GHz & 6GHz Universal Counters

SERVICE GUIDE

Table of Contents

Specifications

Safety

General

Frequency Calibration

C Input Threshold Adjustment

Diagnostic Notes

Battery replacement

Parts List

Specifications

Input Specifications

Input A

Configurable options

Input coupling:

Input impedance:

Attenuation:

Active edge:

Low pass filter:

Trigger threshold:

AC or DC

Ω

or 50

Ω

1:1 or 5:1

Rising or falling, or width high or low

Filter In (~50kHz cut-off) or Out

Variable threshold for both DC and AC coupling

Input Impedance:

Ω

//25pF (DC or AC coupled)

or 50

Ω

nominal (AC coupled only).

Frequency Range:

< 0.001Hz to >125MHz (1M

Ω,

DC coupled).

< 30Hz to >125MHz (1M

Ω,

AC coupled).

< 500kHz to > 125MHz (50

Ω,

AC coupled).

Trigger Threshold:

DC coupled:

AC coupled:

0 to 2V (1:1 attenuation) or 0 to 10V (5:1 attenuation).
Average ± 50mV (1:1 attenuation) or ± 250mV (5:1 attenuation).

Sensitivity:

Sinewave - 15mV

rms

30Hz to 100MHz, 25mV to 125MHz

at optimum threshold adjustment.

Input B

Input Impedance:

Ω

nominal (AC coupled).

Frequency Range:

< 80MHz to >3GHz.

Sensitivity:

12mV

rms

80MHz to 2GHz, 25mV

rms

to 2.5GHz, 50mV

rms

to 3GHz.

Maximum Input Signal:

< 0dBm recommended, +13dBm (1V

rms

) maximum.

Input C (fitted to TF960 only)

Input Impedance:

Ω

nominal (AC coupled) in-band. 250k

Ω

at DC.

Frequency Range:

< 2GHz to >6GHz (typically 1.8GHz to 7.5GHz).

Sensitivity:

25mV

rms (

–

19dBm) 2G

Hz to 6GHz.

Maximum Input Signal:

< +16dBm (1.5Vrms) recommended. Damage level +25dBm (4V

rms

External Reference Input

Input Impedance:

>100k

Ω,

AC coupled.

Frequency:

10MHz.

Signal Level:

TTL, 3V

to 5V

CMOS or 1 to 2V

rms

sinewave.

Maximum Input Voltage

Inputs A, B, C, and
External Reference:

30V

; 30V

rms

50/60Hz with respect to earth ground

Note that the inputs will not be damaged if subjected to an accidental short-term connection to a 50/60Hz
line voltage not exceeding 250V

rms

, or 250V DC.

Timebase

Measurement Clock:

50MHz.

Internal Reference oscillator:

10MHz TCXO with electronic calibration adjustment.

Oscillator Temperature Stability:

Better than ± 1ppm over rated temperature range.

Initial Oscillator Adjustment Error:

< ± 0.2ppm at 21ºC.

Oscillator Ageing Rate:

< ± 1ppm first year.

Calibration adjustment range:

> ± 8ppm.

Measurement Functions

Frequency (Inputs A, B or C)

A Input Frequency Range:

< 0.001Hz (DC coupled) to >125MHz

B input Frequency Range:

80MHz to >3000MHz.

C input Frequency Range:

<2Ghz to >6GHz.

Resolution:

up to 10 digits (see below) or 0.001Hz

Period (Inputs A, B or C)

A Input Period Range:

8ns to 1000s (DC coupled)

B input Period Range:

0.333ns to 12.5ns

C input Period Range:

0.166ns to 0.5ns

Resolution:

up to 10 digits (see below)

Pulse Width Modes (Input A only)

Functions:

Width high or low, ratio H

L (high time to low time) or duty cycle.

Pulse Width Range:

40ns to 1000s

Averaging:

Automatic within measurement time selected, up to 50 pulses.

Resolution:

20ns for one pulse; up to 1ns or 10 digits with multiple pulse
averaging. 0.01% for Ratio H

L and Duty Cycle.

Total Count (Input A only)

Count range:

1 to 9 999 999 999

Minimum pulse width:

8ns

Frequency Ratio B:A

Resolution:

Equal to the resolution of the two frequency measurements.
If the ratio exceeds ten digits, displays six digits plus exponent.

Measurement Time

Selectable as 100s, 10s, 1s or 0.3s. The instrument displays the average value of the input
signal over the measurement time selected, updated every 2s, 1s, 0.5s or 0.3s respectively. The
hardware captures the count values and continues measuring without any dead time.

Resolution

The displayed resolution depends upon measurement time and input frequency. The basic
resolution of period is 8 digits for every 2 seconds of measurement time. Frequency resolution is
the reciprocal of period resolution. Usable resolution can be reduced by noise at low frequencies.

Accuracy

Measurement accuracy is timebase accuracy + measurement resolution + 2 counts.

Operating Facilities

Noise Filter (Input A only)

The Filter key controls a low pass filter, with a cut-off frequency of about 50kHz, to assist in
obtaining stable readings at low frequencies.

Hold

Pressing the Hold key will hold the current measured value in the display, with the Hold indicator
on, until the Hold key is pressed again. The measurement continues in the background when
Hold is on. A long press on the Hold key clears old data and restarts the measurement.

Intelligent Power Switching

The unit automatically selects the best available power source of AC adaptor, USB or battery.
Intelligent switching avoids discharging the battery overnight when operated from externally
switched AC power.

A press-to-measure facility allows a quick measurement to be made by pressing a function select
key which will power the instrument up in the corresponding function. The instrument will
automatically switch off 15 seconds after the last key-press.

Remote Control

All capabilities can be controlled remotely and measurements read through a USB port.

The instrument can be powered (but the battery cannot be charged) by the USB host.

Interface:

Serial port emulation over USB.

Current consumption:

< 100mA (<5mA if AC adaptor power is present)

Command set:

Instrument specific. TF830 and TF930 compatible.

Power Requirements

The instrument has fixed internal rechargeable batteries and is supplied with a universal voltage
external mains adaptor with interchangeable UK, Euro, Australian and US power connectors.

Battery Type:

Three 2500mAh NiMH cells.

Battery Operating Life: Typically 24 hours

Low Battery Indicator:

‘Lo Bat' shows in display when approximately 10% of battery life remains.

Recharge Time:

< 4 hours

Adaptor Supply range: 85 to 240V, 50 or 60 Hz,

Power consumption:

5W max at DC input to unit; 15VA max at AC adaptor input (charging).

General

Display:

10 digit LCD, 12.5mm high (0.5”). Annunciators show input
configuration, operating mode, measurement units and gate time.

Operating Range:

+5°C to +40°C, 20% to 80% RH

Storage Range:

–

20°C to +60°C

Environmental:

Indoor use at altitudes up to 2000m, Pollution Degree 2

Size:

260mm(W) x 88mm(H) x 235mm(D)

Weight:

1050 gms (plus 170 gms AC adaptor)

Electrical Safety:

Complies with EN61010-1

EMC:

Complies with EN61326

Safety

Universal Counter

This instrument is Safety Class III according to IEC classification and has been designed to meet
the requirements of EN61010-1 (Safety Requirements for Electrical Equipment for Measurement,
Control and Laboratory Use).

This instrument has been tested in accordance with EN61010-1 and has been supplied in a safe
condition. This instruction manual contains some information and warnings which have to be
followed by the user to ensure safe operation and to retain the instrument in a safe condition.

This instrument has been designed for indoor use in a Pollution Degree 2 environment in the
temperature range 5°C to 40°C, 20% - 80% RH (non-condensing). It may occasionally be
subjected to temperatures between +5° and -10°C without degradation of its safety. Do not
operate while condensation is present.

Use of this instrument in a manner not specified by these instructions may impair the safety
protection provided.

WARNING!

All accessible parts will be at the same voltage as the outer of the signal input sockets.  In
particular, note that the shell of the USB connector is galvanically connected to the body of the
N-type and BNC inputs and will therefore be at earth ground potential when the USB port is
connected to a desktop PC. However, to maintain user safety under all other circumstances it is
essential that no input is connected to a voltage above 30Vdc or 30Vrms with respect to earth
ground   which is the limit of Safe Extra Low Voltage (SELV) by IEC definition. Note that
although the inputs will withstand short-term accidental connection to an AC line voltage up to
250Vrms, 50/60Hz, users will be at risk if the instrument 'ground' is connected to such hazardous
voltages.

The instrument shall be disconnected from all voltage sources before it is opened for any
adjustment, replacement, maintenance or repair. Any adjustment, maintenance and repair of the
opened instrument under voltage shall be avoided as far as possible and, if inevitable, shall be
carried out only by a skilled person who is aware of the hazard involved.

Do not wet the instrument when cleaning it.

The following symbols are used on the instrument and in this manual.

Adaptor/Charger

The adaptor/charger supplied has a universal input voltage rating of 100-240VAC, 50/60Hz. It is
a Class II (double insulated) device, fully approved to EN 60950-1 (2001), UL 60950 (UL listing
E138754) and AS/NZS CISPR:2002 (C-Tick).

Use ONLY the AC adaptor/charger provided by TTi with the instrument.
Use of any other power source may damage the unit and will void the
warranty.

Direct Current

CAUTION – refer to accompanying documentation.
Damage to the instrument may occur if these precautions are ignored.

meaning that the marked terminal is connected to accessible
conductive parts.

General

Service Handling Precautions

Service work or calibration should only be carried out by skilled engineers using high quality test
equipment. If the user is in any doubt as to his competence to carry out the work, the instrument
should be returned to the manufacturer or their agent overseas for the work to be carried out.

This simplified service guide only details the routine calibration procedure and the dismantling of
the instrument to PCB assembly level. If a PCB assembly is suspected as being faulty it should
be returned to the manufacturer or their agents overseas for repair or replacement. The Parts
List gives the part numbers of each PCB assembly, together with the mechanical parts and
fasteners that can be easily replaced by the user.

Dismantling the instrument

Note that calibration of the oscillator frequency does not require the instrument to be opened.
Refer to the procedure in the next section.

Disconnect the instrument from all input signals, the USB connection and the AC adaptor.

Unclip the front bezel by gently pulling the centre of each long edge up and forward.

The case halves are held together by 4 plastic push-rivets.

Lift off the case upper, leaving the front and rear panels in the base of the unit.
The instrument can be operated in this condition for fault diagnosis. If adjustment of the C
input threshold setting is all that is required, no further dismantling is necessary.

Otherwise, disconnect the ribbon cable from the rear of the Main (front panel) PCB.

Before removing the rear panel or the Battery/USB PCB, note the position of the
grounding spring attached to the USB socket. The PCB is attached to the case lower with
4 screws. To avoid short-circuiting the batteries, do not place this PCB on a conducting
surface. When reassembling, take care not to damage the USB spring.

To remove the Main PCB from the front panel, first pull the knob off its shaft, lift the Front
Panel assembly from the base of the unit and lay it face down on a soft surface to avoid
damaging the LCD. Keeping the metal panel flat and upside down, remove the screws
holding the PCB to the front panel and lift it off, leaving the loose keycaps in the metal
panel. Collect and store the keycaps for reassembly.

The C input PCB may be separated from the Main PCB by removing the nut from the N-
type connector and pulling the PCB backwards off the connecting pins. On reassembly,
align these pins carefully. The washer fits between the flange of the N-type connector and
the rear of the Main PCB. Retighten the nut firmly, to put the washer under compression.

Reassemble in the reverse order. Take care when reassembling the Main PCB to the
metal front panel that all of the keycaps are correctly aligned. Connect the ribbon cable
and test the unit for correct operation before reassembling the case.

Use the blade of a small screwdriver to remove
the snap-lock rivets as follows:

First, ease out the head of the rivet using a fine
screwdriver blade under the edge of the head
(Fig.a). With the rivet head fully out, the body
of the rivet can now be eased out with the
screwdriver blade and removed completely

(Fig.b). To re-assemble, fully re-insert the body
of the rivet then push in the head to lock it.

Frequency Calibration

Equipment Required.

A Standard Frequency Source with accuracy ±0.05ppm or better at a frequency of 5MHz or
10MHz. Ideally use a 10MHz Rubidium source. The procedure below assumes 10MHz.

TF930 and TF960 Reference Oscillator Specification.

Temperature coefficient: ± 1 ppm over the full operating temperature range.

Ageing (first year): ± 1 ppm.

Initial accuracy: ± 0.2ppm (at 23ºC) when new.

Recommended recalibration accuracy: ±0.05ppm

Initial Set-up.

Place the unit in the controlled temperature calibration environment and switch on, running from
its batteries. The

Bat

annunciator should show. Allow at least 30 minutes to achieve temperature

equilibrium.

Lo Bat

is shown, connect the mains power unit and allow the unit to charge, which may take up

to four hours. Wait a further one hour after charging completes to allow any internal temperature
rise to dissipate.

Manual Reference Oscillator Frequency calibration.

Connect the standard frequency signal to the A input.

If the unit is on, press

Operate

to switch it off.

Hold down the

Input A/B

key and press

Operate

Release

Operate

when the display appears, then release

Input A/B;

the display should show

Cal ? Y n.

Press the left hand

Measurement Time

key to select Yes.

An annunciator

should be flashing in the display.

In calibrate mode an extra digit of resolution is shown (to speed the process), but note that the
last digit may be in error by more than one count.

Select 50

Ω

Impedance

(with the default AC

Coupling

) and centre the

Threshold

control at the

marker. The display should show the frequency of the standard source, subject to any pre-

calibration inaccuracy.
If the reference signal is large it may be necessary to select the 5:1

attenuator.

The calibration setting is adjusted by pressing the

Frequency

and

Period

keys.

The

Frequency

key raises the oscillator frequency and makes the displayed value lower.

The

Period

key lowers the oscillator frequency and makes the displayed value higher.

The amount of adjustment for each press depends on the Measurement Time setting.

With 0.3s

Measurement Time

selected, note the difference between the reading and

10.00000MHz and press either the

Frequency

Period

key to get a closer result. Each step

moves the oscillator by about 0.2ppm (2Hz at 10MHz). Repeat as needed, aiming to be within
about 4Hz, then move to the next step.

Set the

Measurement Time

to 1s and repeat the process. The adjustment per step is now a

decade smaller and multiple presses may be needed. The measurement restarts after each set
of key presses. It will take a few seconds for the reading to stabilise because of the settling time
of a filter on the control voltage. Aim to be within about 0.5Hz and then move to the next step.

Set the

Measurement Time

to 10s and wait for the measurement to complete (

Measure

stops

flashing and an extra digit appears). Check that the reading is within ±0.05ppm (0.5Hz), making
further adjustment if needed (waiting for Measure to stop flashing after each adjustment). Each
key press moves the oscillator about 0.002ppm (2 counts in the last digit).

Although the calibration value can be set to this precision, this is more accurate than is
necessary, considering the medium term stability of the oscillator. The initial accuracy is specified
at ±0.2ppm on despatch from the factory, but after a unit has aged for a year or more, it is

reasonable to set the calibration value to within ±0.05ppm. This is typical of the variation over
normal room temperature changes during the course of a day.

Finally, press and hold down the

Width

key for a few seconds to store the calibration value in

EEPROM.
Hold the key down until the C annunciator stops flashing and stays off.

Note

: To exit calibration without saving the new value, simply press

Operate

to switch off.

Press

Operate

to switch the unit off, wait a few seconds and then press it again to turn the unit

back on.
Select 50

Ω

Impedance

(and if necessary 5:1

attenuator

). Set the

Measurement Time

to 10s.

Check that the reading is the same (within 1 count) to prove that the new calibration value has
been stored.

If desired, set the

Measurement Time

to 100s, and (after Measure stops flashing) record the

final reading.

C Input Threshold Adjustment

Introduction

The prescaler used in the C input will self-oscillate if no signal is applied. To avoid distracting the
user a signal level detector circuit senses the absence of a useable input signal and disables the
divider to show 0.0 on the display. There is a preset adjustment in this circuit, which might
possibly drift with time. If the threshold is too low, then the unit will show a random count around
7GHz whenever the C input is selected without a signal. If the threshold is set too high, then the
usable sensitivity of the input is impaired.

Equipment required

2 to 6GHz signal generator with reasonably accurate calibrated level around 5 to 15mV.
A microwave grade N-type to N-type coaxial lead. (Do not use a BNC type with adapters).

Procedure

To adjust the setting, first dismantle the unit to the stage of removing the top cover. Identify the C
input PCB, the variable adjustment, a two pin link LK1 and a surface mount LED near the link.

With no signal applied, switch the unit on and select the C input. If 0.0 is displayed, short
together the two pins of LK1. The unstable count should appear; if not, then there is a fault
present.

Apply a CW signal at 3GHz and a level of 6mV. Using a suitable trimming tool, turn the variable
adjustment clockwise until the LED lights (and a count appears on the display). Then turn the
variable adjustment

slowly

anti-clockwise until the LED just extinguishes.

Increase the signal generator level until the LED lights and a count shows; this should be before
12mV. The count should be correct by 15mV. Decrease the signal generator level to 4mV and
check that the LED extinguishes and the display shows 0.0. Check at other frequencies across
the range 2 to 6GHz that the LED remains off at a signal level of 4mV.

Note

This is a general purpose setting which will achieve rated sensitivity, but at some frequencies the
level detector will permit a count with a signal level below that needed to produce a correct count.

Some customers may prefer a higher threshold setting, so that a count does not show until it is
correct. This setting can be performed at the customer’s preferred frequency, but this may
possibly mean that the unit does not meet its sensitivity specification at other frequencies.

Diagnostic Notes

This instrument uses many small surface mount components in critical high frequency circuits.
Component level fault finding and repair is not possible and service is normally performed by
identifying the faulty PCB assembly and returning it to the manufacturer or their field service
agent for repair or replacement. The only field repair possible is the replacement of the
rechargeable battery cells. The following notes are intended to help in identifying which of the
PCBs is faulty.

AC Adaptor

The output voltage of the adaptor can be checked with a DVM: the outer sleeve is the negative
terminal and the voltage should be around 5.2 to 5.3V.

Initial Checks

First check that all keys are free to operate; if any one is stuck down, then the unit cannot
correctly identify keystrokes.

Now remove the top cover of the instrument as described up to step 4 of the disassembly
procedure above.

First try disconnecting and then reconnecting the ribbon cable from the back of the main PCB.
Inspect the insulation displacement connectors and check they are clamped together tightly. If
intermittency is suspected, remove the Charger PCB and check the solder joints on the transition
header.

Otherwise, identify the faulty subsystem by checking the following items in order.

Batteries

Measure the voltage of each cell; they should be similar and between 1.0V (discharged) and
1.45V (fully charged). If any cell delivers below 0.5V it is probably damaged and all three cells
must be replaced, either by field repair (see below) or service exchange.

There is a self resetting fuse in series with the battery. This component is a last resort protection
against fire and any failure indicates that another major fault has occurred.

Note in particular that this component MUST NOT be hand soldered as that will
almost certainly cause an internal short circuit which would negate the protection.

If the cells are charged, but the unit will not function then the fault is almost certainly on the main
PCB. To check, use a DVM to measure the battery voltage on the charger PCB between the test
points T0V (to the right of the USB socket) and TV (in front of the large gold area on the PCB).
Then measure the voltage on the main PCB between T0V (in the bottom left hand corner) and
the hole for pin 1 of the unfitted power socket on the right hand edge of the PCB. If the same
voltage is present here, then the fault lies on the Main PCB.

Battery Charger

Connect the AC adaptor to the unit and switch it on. Check that the input voltage appears
between the test point T0V (to the right of the USB socket) and the input to D2 on the rear-most
of the three gold heatsink areas.

There is a 2A surface mount fuse in the input circuit to this point. The AC adaptor supplied with
the instrument does not have sufficient current capacity to blow this fuse, so if it is open circuit
this indicates that an incorrect AC adaptor has been attached to the unit. Major consequential
damage should be assumed, so replace the whole PCB; do not just replace the fuse.

If the battery voltage is below about 3.3V the charger should start automatically, and the yellow
lamp should show on the panel. The charger may also be started by pressing SW1 on the PCB.
If the charger is active, it will be possible to feel that D2 and Q1 are warm within a few minutes. If
the charger is running but the lamp is not showing then the fault might be in the drive circuit, the
ribbon cable connections or the LED itself.

If a charge termination fault is suspected, return the charger PCB for replacement as it is not
safe to have the batteries continuously charged. There are four different charge termination
circuits and an immediate recharge prevention circuit: do not attempt diagnosis.

USB faults

Use the AC adaptor to power the unit while attempting to diagnose USB problems.

Many USB problems are actually PC configuration issues. The interface device on the charger
PCB is a USB to serial converter: remote control messages are sent to the main system
processor on the Main PCB through an internal serial link. The counter appears as a COM port to
the PC; this is not a “virtual” COM port it is a real one that happens to be connected by a USB
cable. Port properties such as the baud rate must be correctly configured from the PC end of the
link (details are in the User Manual).

The COM port number allocated is chosen automatically during the driver installation. The BIOS
of some older computers prevents proper operation of a USB connected port if the number
allocated is COM3 or COM4; if this happens, use Device Manager to manually configure it to
COM5 or higher. Note also that some old PC software will not communicate with ports above
COM15.

The interface device on the Charger PCB is responsible for the USB enumeration. If the PC
cannot detect the counter as a USB device, then the fault lies here. The switching logic will not
take power from the USB unless the port has been properly enumerated by the host PC.

If the PC can detect the USB device, but functional control of the counter is not possible then
(provided the baud rate etc. are correctly configured) the fault lies with the processor on the Main
PCB, or possibly on the interconnection between.

Note that changing the USB/Charger PCB will change the instrument’s USB serial number,
so it will appear to be a different unit to any PC, which will seek to reinstall the drivers.

Functional Faults

If there is a fault in any aspect of the operation of the A or B inputs, then the Main PCB should be
returned for repair or replacement.

For a TF960, if operation of the A and B inputs is correct, but the C input is faulty, then further
checks may be carried out to determine the location. It may also be worth checking the soldering
on the interconnections.

Switch on the unit and select the C input.

Note:

if the unit has been dismantled and the Main PCB is hanging loose, take care not to

accidentally press one of the keys and change the operating mode while handling the board.

With no signal applied to the C input, short together the two pins of LK1 on the C input PCB. An
unstable count (broadly in the region of 7GHz) should appear on the display.

If a count appears, then the circuits on the Main PCB are functioning correctly and the fault lies
on the C input PCB. It is possible that the signal detector threshold setting is incorrect. If suitable
test equipment is available, attempt the threshold setting procedure below. Otherwise return the
C input PCB for replacement.

If no count appears, then return both PCBs for repair or replacement.

Battery replacement

The battery consists of three 2.5Ah NiMH cells. They are conservatively constructed and should
provide hundreds of charge-discharge cycles. Extended storage or use in high temperature
environments may reduce cell life. If it appears that the discharge time has reduced significantly,
or if the cell voltages have become mismatched, then the cells may be replaced.

Replace all three cells simultaneously, using new cells of the same make and type.
Use only A or AF size 2.5Ah NiMH (Nickel Metal Hydride) rechargeable cells.
Do not use AA size cells. Do not use Nickel Cadmium cells.

Remove the top cover of the instrument and disconnect the ribbon cable from the rear of the
Main PCB. Disconnect the AC adaptor.

Remove the old cells from the unit by cutting the tags attached to the battery and then the tie-
wraps holding them to the PCB. Cut the tags; do not attempt to unsolder them. Tape up the cells
to avoid accidental short circuits and dispose of safely.

Do not incinerate the cells, or place them with domestic waste.
Dispose of them in accordance with local regulations and facilities.
These cells are recyclable.

Early units may be fitted with cells having tags with connecting holes; these are attached to the
PCB with lengths of wire. Current production cells have tags without holes. These are attached
using standard 0.025” square connecting posts taken from a SIL pin header. Clean up the
connections and fit new posts if required.

Note that there is a thermistor near the centre cell which is used by the charger circuit to sense
its temperature. Place a small amount of heatsink compound over the thermistor to ensure good
thermal conductivity.

Place the cells on the PCB, making sure that they are all correctly oriented (they all point in the
same direction) and that the tags are aligned with the correct connecting pads. Secure the cells
to the PCB with tie-wraps (only sufficiently tight to hold the cells – do not bend the PCB).

Finally wrap the tags around the 0.025” square posts and solder as quickly as possible. It is
important not to overheat the seals of the cell.

As quickly as possible, confirm the polarities by using a DVM to check that the voltage between
the test points T0V (to the right of the USB socket) and TV (in front of the large gold heatsink
area) is equal to the sum of the cell voltages – it should be between 3V and 4V.

Reattach the ribbon cable to the Main PCB. The unit should now be functional.

Attach the AC adaptor and provide power; it the cell voltages are low charging will start
automatically, in which case wait a few minutes until the cells are charged past the threshold.

Test the charge termination circuits as follows:

Press SW1 to start charging, then briefly short LK1: charging should stop.

Press SW1 again, then briefly short LK2: charging should stop.

Place a shorting link across LK3 (to run the timer at test speed)

Note the time and press SW1 to start charging; charging should stop in 45 to 55 secs.

Wait a further 60 secs then press SW1 again; charging should not restart.

Disconnect the AC power and remove the test link across LK3. If any of these test fail, return the
PCB for repair or replacement.

Re-apply power, press SW1 and monitor the first charging cycle by watching the yellow charge
indicator on the front panel. Charging must automatically stop within four hours. At the end of the
charging cycle check that the cell voltages are equal within ±50mV and that the temperature of
the three cells feels similar to the touch.

If charging does not automatically stop, then it should be assumed that the old cells were
destroyed by a faulty charging circuit and the whole PCB should be returned for repair.

Parts List

Part Number

Description

Position

Common Items

51151-0820

AC ADAPTOR UNIV 5.2V/1A DC

(WITH CONNECTORS)

44813-0410

PCB ASSEMBLY – CHARGER & USB - TF

(COMPLETE WITH 10W CABLE)

20010-0258

RIVET SNAPLOK 3.6Dx2.7-3.6L GREY

FOR CASE

20010-0259

RIVET, SCREW TYPE

FOR FEET

20073-9801

SCREW No.4x1/4 Plastite

CHARGER PCB TO CASE

20234-0100

SCREW M3x6 C/W WASHER

MAIN PCB TO FRONT PANEL

20662-0590

FOOT - BLACK RBS-1 - S/ADHESIVE

33143-0310

FOOT PLAIN (ROUND) BENCH CASE 2

33143-0320

FOOT BAIL HOUSING BENCH CASE 2

33143-0330

FOOT TILT BAIL BENCH CASE 2

31711-0210

BEZEL - BENCH CASE 2

33536-4380

CASE UPPER BENCH CASE 2

33536-4390

CASE LOWER BENCH CASE 2

33331-9790

REAR PANEL

37113-2183

KEYCAP 8X6MM GREY3 TF

37151-0483

KNOB 21MM D-SHAFT GREY3

38611-0010

COLLAR – BNC – FOAM

20653-0204

CABLE TIE 100 x 2.5mm

FOR BATTERIES

22010-0500

BATTERY 1.2V2.5Ah NiMH AF TAG

35358-0580

EARTHING SPRING USB

SUPPLIED WITH CHARGER PCB

48511-1110CD

CD – UNIVERSAL PRODUCT DATA

INCLUDES USB DRIVERS

TF930 Items

33331-4690

FRONT PANEL – TF930

33331-9780

OVERLAY – FRONT PANEL – TF930

44813-0400

PCB ASSEMBLY – MAIN – TF930

48581-1400

INSTRUCTION BOOK TF930

TF960 Items

33331-1690

FRONT PANEL – TF960

33331-1700

OVERLAY – FRONT PANEL TF960

44813-0430

PCB ASSEMBLY – MAIN – TF960

44813-0440

PCB ASSEMBLY – INPUT C – TF960

48581-1440

INSTRUCTION BOOK TF960

Thurlby Thandar Instruments Ltd.

Glebe Road • Huntingdon • Cambridgeshire • PE29 7DR • England (United Kingdom)

Telephone: +44 (0)1480 412451 • Fax: +44 (0)1480 450409

International web site: www.aimt t i.com • UK web site: www.aimt t i.co.uk

Email: info@aimt t i.com

Aim Instruments and Thurlby Thandar Instruments

Book Part No. 48581-1450

Issue 1