Thanks to all the good advice I've received, I have established that my
problems were probably caused by a battery fault. I have four sets of NiMH
batteries, one of Fujitsu 1600 mAh cells which came with the recorder and
three of Powerex 2200 mAh. With Sets 1, 3 and 4 the Portadisc records on my
desk with phantom power for 3 or more hours. In the field I have been
getting much less with Set 1, but this is probably because I often record
short cuts and certainly because I have recently been experimenting with
using the Portadisc for playback. I have not used Sets 3 and 4 yet in the
There seems to be something wrong with battery Set 2 (Powerex). I used it
twice in the field and each time the recorder went dead after a short time.
On bench tests, after charging the set on my MAHA MH-C777 charger and while
recording with it in the Portadisc (with phantom power), the battery meter
drops from 99% to 90% very quickly (after 6 mins in one test and 20 mins in
a second). In the first test the recorder went dead after 13 minutes but in
the second it lasted for 3 hours when the meter reached 60% and I stopped
the test. Repeated charging and discharging seems to have improved the
battery set's performance. I measured the voltage of the eight cells in Set
2 (with a new multimeter; the old one was giving inaccurate readings which
didn't help the investigation) while it was being discharged by the MAHA,
before the second bench test. At the beginning of the discharge process the
1.32 1.32 1.32 1.32 1.32 1.29 1.31 1.30
and at the end
1.24 1.24 1.24 1.24 1.23 1.23 1.24 1.23
The cells seem well matched and possibly the fault has righted itself.
I was probably using the faulty Set 2 when I failed, several times, to
charge in the Portadisc. I have now successfully used the Portadisc twice
to charge Set 4 (Powerex). It's a long process and, as Walter said, one has
to continue long after the green light goes out.
I can't tell you what a relief it is to be fairly confident that my
Portadisc is probably not faulty! And I'm tremendously grateful to Walter,
Marty, Rich, Klas and Martyn who have given me help and encouragement.