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NeXTcube No Power -- why?

 
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ErikTheHack



Joined: 03 May 2006
Posts: 76
Location: San Diego, CA

PostPosted: Sun Oct 09, 2016 6:20 pm    Post subject: NeXTcube No Power -- why? Reply with quote

I pulled my cube out of mothballs today and set it all up (as I finally have a place for it again) and when I hit the power button on the keyboard, no joy!

No click, buzz or zoom. No fan. Nothing.

What is the most common cause of this condition. It worked fine the last time I fired it up back in late 2011.

The cube is an 040 with a dimension board. The only thing I could think think of was the lithium battery. I measured it and it's at 2.860V and ~129.3mA.

It's rated at 2/3A 3V battery. So 2/3A is like ~666mA right?

Any other ideas? Thanks in advance.
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ND '040 NeXTcube [SN: ABA0004306], NeXTStation Turbo Color ADB, HP PA-RISC 712/80, HP PA-RISC 712/100, Sun SPARCSTATION 5, Sun SPARCSTATION 20
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cubist



Joined: 20 Sep 2007
Posts: 246
Location: Cambridge, MA

PostPosted: Sun Oct 09, 2016 9:44 pm    Post subject: Re: NeXTcube No Power -- why? Reply with quote

ErikTheHack wrote:

The cube is an 040 with a dimension board. The only thing I could think think of was the lithium battery. I measured it and it's at 2.860V and ~129.3mA.

It's rated at 2/3A 3V battery. So 2/3A is like ~666mA right?

I hope this is a joke...

2/3A is a size, not a peak current rating (which is mostly something documented for car batteries and similar applications).

Given the slightly low voltage and what I assume is a short-circuit current reading, start by replacing the battery.

Also suggest you never measure current again.
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ErikTheHack



Joined: 03 May 2006
Posts: 76
Location: San Diego, CA

PostPosted: Mon Oct 10, 2016 10:39 am    Post subject: Re: NeXTcube No Power -- why? Reply with quote

Quote:

I hope this is a joke...

2/3A is a size, not a peak current rating (which is mostly something documented for car batteries and similar applications).

Given the slightly low voltage and what I assume is a short-circuit current reading, start by replacing the battery.

Also suggest you never measure current again.

No. It wasn't. Gee, you're right of course. "2/3A" _IS_ a size. Embarassed I guess I should have googled it FIRST.
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wa2flq



Joined: 18 Dec 2008
Posts: 30
Location: Chicagoland

PostPosted: Mon Oct 10, 2016 2:07 pm    Post subject: Re: NeXTcube No Power -- why? Reply with quote

ErikTheHack wrote:
Quote:

I hope this is a joke...

2/3A is a size, not a peak current rating (which is mostly something documented for car batteries and similar applications).

Given the slightly low voltage and what I assume is a short-circuit current reading, start by replacing the battery.

Also suggest you never measure current again.

No. It wasn't. Gee, you're right of course. "2/3A" _IS_ a size. Embarassed I guess I should have googled it FIRST.


Shorting lithium or similar high energy density cell could easily create a fire or explosion hazard.

Load testing is a reasonable way to test a battery, provided you have a good guide on the battery capacity and load resistance selection. Zero Ohms is never a good value around here.
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pentium



Joined: 23 Jun 2006
Posts: 1148
Location: Kamloops, BC

PostPosted: Tue Oct 11, 2016 9:06 pm    Post subject: Re: NeXTcube No Power -- why? Reply with quote

wa2flq wrote:


Shorting lithium or similar high energy density cell could easily create a fire or explosion hazard.


While shorting any battery is not recommended the chemistry of these small lithium cells are such that they are not as willing to burst into flame or explode in any fashion. Please do not compare these with more modern lithium cells.

Someone accidentally poking at it in amps mode for a few seconds isn't gonna kill it either. Load testing is not required on these batteries. Treat it like any other battery, like a AA cell. You see a voltage, it's good.
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ErikTheHack



Joined: 03 May 2006
Posts: 76
Location: San Diego, CA

PostPosted: Thu Oct 13, 2016 7:12 pm    Post subject: Thanks Reply with quote

Thanks guys. I am aware of the hazards here but caution warnings never hurt. FYI I was pretty confident that a sub-second Amperage test with my trusty multi-meter wouldn't have explosive results once especially once I had measured that the Voltage was low. I should have recognized that the 2/3A was a TYPE and not a measure. I blame 420 tinkering and posting. Sorry for the noise.
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