Hameg HM 303-4, Service Manual

Subject to change without notice

3

30MHz Standard Oscilloscope HM 303

Accessories supplied: Line cord, Operators Manual, 2 Probes 1:1/10:1

Specifications

Vertical Deflection

Operating modes:

 Channel I or II separate,

both Channels (alternated or chopped),
(Chopper frequency approx. 0.5MHz).

Sum

 or 

difference

 with Ch. I and Ch. II

(both channels invertable).

XY-Mode: 

via channel I and channel II

Frequency range:

 2xDC to 30MHz (

−

3dB)

Risetime: <12ns.
Overshoot 

≤

1%.

Deflection coefficients:

 12 calibrated steps

from 5mV/div. to 20V/div. (1-2-5 sequence)
with variable 2.5:1 up to 

50V/div.

Accuracy in calibrated position: ±3%

Y-expansion x5

 (calibrated) to 

1mV/div.

 (±5%)

in the frequency range from DC - 10MHz (–3dB)

Input impedance:

 1M

Ω

 II 20pF.

Input coupling: DC-AC-GD (ground).
Input voltage: max. 400V (DC + peak AC).

Triggering

Automatic: 

(peak to peak)

 <20Hz-100MHz 

(

≤

 0.5div.)

Normal with level control: 

DC-100MHz

(

≤

0.5div.)

ALT. Triggering; LED indicator

 for trigger action

Slope: positive or negative,
Sources: Channel I or II, CH. I alternating CH II,

line, external

Coupling:

AC

 (10Hz to 100MHz),

DC 

(0 to 100MHz),

LF

 (0 to 1.5kHz)

Active TV-Sync-Separator

 (pos. and neg.)

External:

≥

0.3

p-p

 from 30Hz to 30MHz

Horizontal Deflection

Time coefficients: 

20 calibrated steps

from 0.2s/div. - 0.1µs/div. in 1-2-5 sequence
Accuracy in calibrated position: ±3%.
Min. speed incl. variable 2.5:1 up to  0.5s/div.
with X-Mag. x10: ±5%; 10ns/div.: ±8%

Holdoff time:

 variable to approx. 10:1

Bandwidth X-amplifier:

 0-3MHz (

−

3dB).

Input X-Amplifier via Channel II,
(sensitivity see Channel II specification)

X-Y

 phase shift: <3° below 220kHz.

Component Tester

Test voltage:

 approx. 6V

rms 

(open circuit).

Test current:

 approx. 5mA

rms

 (shorted).

Test frequency:

 approx. 50Hz

Test connection: 2 banana jacks 4mm 

∅

One test lead is grounded (Safety Earth)

General Information

CRT:

 D14-364GY/123 or ER151-GH/-,

6" rectangular screen (8x10cm)
internal graticule

Acceleration voltage:

 approx 2000V

Trace rotation:

 adjustable on front panel

Calibrator:

 square-wave generator (t

r 

<4ns)

≈

1kHz / 1MHz; Output: 0.2V ±1% and 2V

Line voltage: 100-240V AC ±10%, 50/60Hz

Power consumption:

 approx. 36 Watt at 50Hz.

Min./Max. ambient temperature: 0°C...+40°C

Protective system:

 Safety class I (IEC 1010-1)

Weight: approx. 5.6kg, color: techno-brown
Cabinet:

 W

 285, 

H

 125, 

D

 380 mm

Lockable tilt handle

5/96

Screen photo of 1 MHz square wave signal

Screen photo of 50 and 100MHz
sine wave with alternate triggering

The new 

HAMEG

HM303

 oscilloscope succeeds the HM203 (over 170,000

sold worldwide). The bandwidth has been extended from 20 to 

30MHz

, the sweep

rate increased to 

10ns/div.

 and improvements added to the already legendary

HAMEG 

auto triggering system. The 

HM303 

is the ideal instrument for waveform

display in the 

DC

 to 

100MHz

 frequency range.

A key feature of this oscilloscope is the vertical amplifier's pulse fidelity, limiting

overshoot to only 1%. The 

HM303

 offers a special fast rise time 

1kHz/1MHz

Calibrator

, permitting high quality probe compensation across the entire frequency

range to ensure probe-tip thru to display integrity. An 

Overscan Indicator

 assists

in vertical display amplitude and position adjustment.

The 

HM303

 is capable of triggering on input waveforms over 

100MHz 

and on

signal levels as small as 0.5 division. 

Alternate triggering

 mode enables the

display of two asynchronous signals simultaneously. An active 

Video Sync-

Separator 

permits detailed examination of complex TV signal inputs. A well

proven, built-in 

component tester

 is now equipped with a stabilized measuring

voltage. The use of a switching type of power supply minimizes both weight and
power consumption and universally accepts a wide range of input power line
voltages, without the requirement to change jumpers or switch positions. The

HM303's

 CRT is fully 

mu-metal shielded

 against outside magnetic fields.

HAMEG

 is setting new 

price/performance 

breakthroughs with the introduction

of this fine oscilloscope. This performance packed scope will tempt all users to run
it through its paces.

OSCILLOSCOPES

Dual Channel, DC to 30MHz, 1mV/div.; Overscan Indicator

Time Base: 0.2s to 10ns/div.; Variable Holdoff; Alternate Triggering

Triggering: DC-100MHz; Auto Peak to Peak; Active TV-Sync-Separator

Additional Features: Component Tester, 1kHz/1MHz Calibrator