Service Manual Miditron
®
Junior
II
/ ID 1997491 / MJ / 1.0 - June 1998 / Page 60
10. Electronics
10.2
Power supply
Mains power is supplied via an external mains power supply
(Fig. 30). The mains power inlet is protected with pigtail
fuses 1.25A/slow at 2 contacts. The mains power supply
provides supply voltages of +5V to +12V to the instrument.
PTCs (poly switches) act as current limitation for both
voltages. The PTCs are resettable. They turn on again once
an error is corrected after responding.
The output voltage is connected to the rear of Miditron
®
Junior
II
via an 8-contact jack connection (Fig. 30) and a
screened power cable of 1 m of length with a Western plug
moulded on both sides and directly enters the Master-
Board. The instrument is connected to the mains power via
a mains cable with an appliance inlet plug.
The supplied version of the connecting cable
has an integrated ferrite core at one end, which
is the end that has to be connected to Miditron
®
Junior
II
.
Current limitation makes the ouput statically and dynami-
cally short-circuit proof yet not permanently overload
protected. Longterm current overloads exceeding 1.5 times
the nominal current may cause damage to the mains power
supply. Genuine short circuits will not cause damage,
however.
Fig. 30
Fig. 59
Electric Data 12V Output
Nominal voltage:
+12V
adjusted to:
+12V
Adjusting accuracy:
±1%
Static accuracy:
±5%
Voltage standing wave
ratio (100Hz)
<120mV p-p
Oscillation amplitude:
<120mV p-p (Ripple and Noise)
Nominal current:
1.6A
Cut-off of current
limitation:
approx. 3.7A @ Ue=110V
approx. 6.1A @ Ue=230V
Table: tab-19e
