[comp.sys.handhelds] Open HP28S case ? 4 FAIL ???

envwpk@epb2.lbl.gov (Werner P. Keilholz) (05/14/91)

"Hallo world \n" :-) ,

I wonder whether anybody ever tried to open the case of a hp28S ?

I would never ask such a brutal question if my hp28S wasn't broken,...
it says "4 FAIL" upon self-test. So my last hope is to find the
usual loose wire inside, but how to *get* inside ???
HP's standard service fees for repairing the 28 here in Germany
are so way out of bounds that I'd rather throw it away than having it
fixed (for the equivalent of about $180 !!!).
Does anybody know what "4 FAIL" means ? (Actually it's "5 FAIL if
I try the "step-by-step-selftest" (the one that requires input
from the keyboard). 

Any ideas are highly appreciated.

Thanks in advance,

Werner

-----------------------------------------------------------------------------
Werner Keilholz                  Georg -            _____
Kuenhoferstrasse 2 / #32                 Simon -   |     |
D-8500 Nuernberg                                   | OHM |    Fachhochschule
Federal Republic of Germany                        _\   /_    Nuernberg
E-mail: KEILHOLZ@CNVE.RRZE.UNI-ERLANGEN.DE

rabe@tabaqui.informatik.rwth-aachen.de (Ralf Bergs) (05/15/91)

envwpk@epb2.lbl.gov (Werner P. Keilholz) writes:

[..]
>I wonder whether anybody ever tried to open the case of a hp28S ?

>I would never ask such a brutal question if my hp28S wasn't broken,...
>it says "4 FAIL" upon self-test. So my last hope is to find the
>usual loose wire inside, but how to *get* inside ???
[..]

You definitely won't find any loose wires inside the case. It's all in SMT,
two PLCC chips only.
There is a parisian handheld club called PPC who managed to open the case
(even to close it again!!!). Maybe you should try to get into contact with'em.
>Werner


CU, Ralf
--
smail: Ralf G. R. Bergs, H"uckeswagener Str. 42, D-5270 Gummersbach-Windhagen
phone: (+49) 22 61-2 19 68
email: rabe@cip-s01.informatik.rwth-aachen.de

admerlev@immd4.informatik.uni-erlangen.de (Arnd Merlevede) (05/15/91)

rabe@tabaqui.informatik.rwth-aachen.de (Ralf Bergs) writes:

>envwpk@epb2.lbl.gov (Werner P. Keilholz) writes:

>[..]
>>I wonder whether anybody ever tried to open the case of a hp28S ?

I did , but only because i spilled a cup of milk over it ...
(But i was too fast, i should just have waited till it dried
without me opening it)
I was that fast , because i always wanted to do the i/o modification
descibed in courbis fine book, which describes how to connect
to an appleII.
I was able to do that, but its lot of work to open (i.e. drill out
around 50 plastic nipples,( thats what i call them ...)) and
to close (glue it together again, with superglue and each nipple
by itself, while pressing hard. Even though i did so, i now have
some keys with a somewhat soft touch)

To do Error fixing is prbably impossible, theres really only a handfull
smd chips and nothing else (besides maybe even one resistor and a 
capacitor 8-)

So i wouldnt open it again, even with that connection to my apple
which is far too slow and complicated.

Arnd


>>I would never ask such a brutal question if my hp28S wasn't broken,...
>>it says "4 FAIL" upon self-test. So my last hope is to find the
>>usual loose wire inside, but how to *get* inside ???
>[..]

>You definitely won't find any loose wires inside the case. It's all in SMT,
>two PLCC chips only.
>There is a parisian handheld club called PPC who managed to open the case
>(even to close it again!!!). Maybe you should try to get into contact with'em.
>>Werner


>CU, Ralf

Hallo Ralf , wusste gar nicht, dass Du auch einen HP hast ...


>--
>smail: Ralf G. R. Bergs, H"uckeswagener Str. 42, D-5270 Gummersbach-Windhagen
>phone: (+49) 22 61-2 19 68
>email: rabe@cip-s01.informatik.rwth-aachen.de
---
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