|Re: HP-38E restore project|
Message #3 Posted by Alberto Fenini on 5 Dec 2009, 8:22 a.m.,
in response to message #2 by Vieira, Luiz C. (Brazil)
Thank you very much for the picture, it has been really useful, and may be could be of interest what I have done : as first step I have completely dissambled the unit, and with a soft iron brush (dremel) cleaned the pcb
to avoid any possible bad contact.
Then, with a light solution of warm water and Marseille soap the I have washed, rinsed and brushed (this time with a plastic brush) the keys and the skeleton
All the plastic items have been then polished with a teflon polisher
At this point, feeding power with cables, I have performed a self test, which proved that the contatc problems beetween pcb and ICs were fixed. However, the display has been soldered to the PCB, using a 16W solder wich has not melted the plastic foil.Display RED plastic was removed for separate polishing
Now comes the interestegin part, I have tried to restore the battery contacts at best, and your suggestion will be very helpful at this point.
I have drilled the old rivets, and separate the foil that hold the contacs, this has been cleaned till bringing the copper at view, and lightly soldered.
Then, using some NICD Battery terminals (which I usually remove) I have cutted something close to old battery contacts, and I have soldered them from the battery caveau side. One more step, I have inserted a very small screew and soldered the backside. Finally, I have soldered the plastic foil for best contact
Last but not least, assembled back the unit, inserted a pack of fresh batteries and re-executed the self test.
How does it look ? Again, thank you very much to everybody and in this case to Vieira, Luiz C. (Brazil)! Take care Alberto