Funny 788T ext powering issue

[pkautzsch]

Yesterday I experienced a funny issue with an externally powered 788T.

The power source was, apparently, somewhat less reliable and dropped out a few times. Normally the 788T should switch to the "internal" (back side) battery, but it didn't. Instead it just went OFF without saving.

Anybody else experienced this?

 

[studiomprd]

troubleshooting 101:

battery properly connected ?

battery good (charged)  "

[Matt Bacon AMPS]

I'll ask the question (don't take it the wrong way)... the 788T battery was charged? Sometimes hired 788's are not setup to charge their batteries from any external power connected. Just a thought?

[RPSharman]

An old battery will barely last long enough to notice the ext supply has gone off line. That's especially the case if it hasn't been kept charged and periodically used. As noted above, people likely rent 788T for use in a bag and may disable charging function to preserve battery power.

[Peter Mega]

Check your ext power function in the menu. If its set to turn on/off when power connected/disconnected, then yes, your machine will power down if power is lost externally

[studiomprd]

" in the menu "

covered in the manual

[montybuckles]

i had a similar issue once... 788 once would turn on, flash to life, then die when plugged into the BDS. the 'internal battery' was charged. it turned out that the power plug wasn't fully seated into the 788. once it was it was fine and i never had the issue again.

[pkautzsch]

Thank you for the suggestions.

It's most similar to montybuckles' issue, however the plug was / is fully seated.

Of course I did check the usual power suspects, and I've been working with the 788T a lot, but never had this issue before.

On-board battery is good and works fine when EXT power cable is removed. Ext Power Function is disabled, and on unplugging an external power source switching to internal works fine too.

Basically it comes down to wondering why the unit doesn't even power down properly but just go off without closing files on what seems to be a power loss.

Suspecting a short somewhere in that cable. Can't find one though.

[montybuckles]

now that i think about it, the cable to the BDS wasn't seated into the BDS properly, not the cable into the 788 - but, it was the same problem/solution....

[Marc Wielage]

Watch out on that 788 front panel: be sure to look for the EXT readout on the upper left. If it says "BATT 7.2" or something like that, that's the internal battery; if it says "EXT 13.4" or something along those lines, you're safe. A few times, I've been caught by surprised with a connector or BDS issue (and even in a few cases, with an AC problem when I was powering the 788 via the AC adapter). 

 

Page 93 of the manual deals with the Power -> Battery Charger menu and various options. 

[pkautzsch]

The EXT power cable we used had a bad insulation inside. So it was a short that the 788 didn't want to cope with.

 

Still find it a bit strange that it doesn't switch to INT when EXT is shorted, but probably there's no way to do this without risking damage.