Jeremy Minns wrote:
> Fascinating stuff, Marty.
> Before your e-mail arrived I left the Portadisc on Record/Pause with no m=
> and the battery pack lasted 4 hours. I now have the Portadisc beside me a=
> I type, with a second battery pack and recording with an MKH20 on phantom=
> power. The battery life meter is fluctuating between 99% and 85% (it has=
> now settled on 95% - whoops 90%). Disaster - now it's switched off
> completely - after 12 minutes! And the voltage of this battery set, which=
> was 14.3V when I started is still 13.7V. It looks as if I shall be taking=
> my old cassette recorder to Amazonia!
> I've now put the second battery pack back in the Portadisc. It showed 90%=
> fell immediately to 70% and then, when I started to record, switched off.
> I'll follow your suggestions to find out if I have a dud cell somewhere.
Also try some other phantom powered mic. And try them on each input
separately. If it does 4 hours without a mic and then dies fast with
one, there's a short or something in the input jacks, the mics, the
connecting cables or the phantom power. Straight phantom power running
right won't draw enough to do your symptoms.
Though you should repeat the no mic test, but in record. Just in case
it's the drive motor for the disk or something like that.
I use two MKH20's with mine without noticing much sortening of record
life. Same with all my other MKH.
While my Portadisc will vary it's battery indication, there is no wild
jumping around like you describe. Back and forth a few percentage points
at most at any given time.
Note you need to measure the voltage of a battery under load. The
unloaded voltage is not very meaningful. Stick it into the Portadisc and
measure the voltage while the Portadisc is running. The voltage will be
lower. If the voltage stays up under load and the Portadisc switches
off, then it's not battery. Remember 1.2 volts X 8 is 9.6 volts. That's
about what you should find when the batteries are 80% discharged. They
should still be running the Portadisc at that point.
I hate to say it, but this does not sound like battery to me.