17 Jul
2024
17 Jul
'24
3:01 p.m.
On Tue, Jul 16, 2024 at 18:13 PM Joshua Rice <rice43(a)btinternet.com> wrote:
I imagine it's quite difficult. Maybe not
"functional Twiggy drive"
difficult, but probably "unmolested 128k Macintosh" difficult.
It of course depends on who you know, and who you ask. Undoubtedly
there's a guy out there with a stack of them in a shed somewhere, but
getting hold of him is a different matter entirely.
I think this person exists and is relatively easy to contact: it's Rob
Blessin of Black Hole Inc (https://next.blackholeinc.com/). If he doesn't
have a 68030 board, ask around on the NeXT forums at
https://www.nextcomputers.org/forums/ (I think these are also related to
Rob in some way).
In my experience the SMT capacitors pose a much greater threat to NeXT PCBs
than the battery: these are classic early 90s caps that must be assumed to
be leaking already. Replace them. Same goes for several of the through-hole
caps in the N4000-series mono displays (ELNA "Long Life" my foot ---
you'll
find they come out moist and fishy-smelling). (Plus there are SMT caps in
the display's digital board too.)
As for the bright yellow Panasonic BR-2/3A lithium primary cell battery: I
issue a challenge to this community. I've never seen one leak. Nobody I've
asked has ever seen one leak. Rob Blessin who has handled thousands of NeXT
boards has never seen one leak. It's a bit maddening since batteries are
supposed to leak eventually and the Panasonics just seem like they...
don't. In fact, they often still hold a good voltage, and I'll confess
here: *I'm still running some of the 30-year-old originals in my NeXTs!*
The replacements I got from DigiKey a few years back are sitting in my
component stores gathering dust, just waiting.
The challenge: have *you* ever seen a leaky Panasonic BR-2/3A lithium
primary cell battery?
Surely their day will come someday --- we'll see them start to go. But for
now it sure feels like we're in the long, low bottom of a very big
bathtub-shaped curve.
--Tom
Josh Rice
On 16/07/2024 17:24, Bill Degnan via cctalk wrote:
how hard is it to track down a replacement NeXT
cube motherboard?
Bill
On Tue, Jul 16, 2024 at 11:38 AM John Robertson via cctalk <
cctalk(a)classiccmp.org> wrote:
> On 2024/07/16 6:28 a.m., Paul Koning wrote:
>>> On Jul 16, 2024, at 9:05 AM, John Robertson via cctalk<
> cctalk(a)classiccmp.org> wrote:
>>> I'm just starting to clean up a NeXT system that a friend has had in
> storage for decades...
>>> I assume the thing has a battery somewhere - I just hope it isn't
> Ni-Cad!
>> At that age it might well be. So what? I think they are still
> available. Or you can replace it by a non-rechargeable battery. That's
> what I did with the ToD clock battery in my Pro; a lithium coin cell
with a
> series diode to prevent "charging"
is not an ideal solution but
adequate,
> and it would be better if I used a Schottky
diode rather than a plain Si
> rectifier diode I happened to have lying around.
>> paul
> Battery leakage was the issue - having dealt with a great many logic
> boards damaged or destroyed by leaking Ni-Cad batteries.
>
> I've since seen a photo of the inside of the NeXT and it looks like they
> used a plug in Lithium battery, so that risk is no longer of much
> concern to me.
>
> John :-#)#
>