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Schematics for HP38E
05-15-2017, 04:11 PM
Post: #1
Schematics for HP38E
I recently received a nonfunctional HP38E and am now attempting to repair it. The battery compartment looks good and there doesn't appear to be any leakage anywhere. Opening up the calculator reveals it is one of the earlier models that is held together by clips. Does a repair manual exist for the Spice series of calculators? If not, does anyone have a schematic of the power supply board so I can make sure that it is working properly? Thanks.

Jack
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05-15-2017, 04:41 PM (This post was last modified: 05-15-2017 04:44 PM by Geoff Quickfall.)
Post: #2
RE: Schematics for HP38E
Hello Jack!

Failure modes on the Spice series:
  • New battery design is larger then design used in calculator resulting in broken battery contact tabs.
  • Battery corrosion affecting battery compartment.
  • Corrosion affecting power flex ribbon.
  • Compression of foam compression substrate causing loose IC connections
  • Oxidation of foam compression substrate traces.
  • Various case cracks from bad attempts to separate shell or dropping. Weak plastics.
  • Display issues, especially on the floating IC version,

As far as wiring diagrams of the power supply, i direct you to this site, (Kees VanderSanden's excellent HP site) scroll down to find the spice series power supply schematic:

Power supply diagrams

Various articles for opening the shell and spice restorations.

Links at bottom of page

Cheers, Geoff





This is not directed at anyone in particular but web searches (google etc) are your friend.
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05-15-2017, 06:22 PM
Post: #3
RE: Schematics for HP38E
Geoff,

Thanks. I think I saw this before, but promptly forgot about it (I definitely need to work on my search engine prowess).

Jack
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05-15-2017, 07:39 PM (This post was last modified: 05-15-2017 07:39 PM by PANAMATIK.)
Post: #4
RE: Schematics for HP38E
(05-15-2017 06:22 PM)jwhsu Wrote:  Geoff,

Thanks. I think I saw this before, but promptly forgot about it (I definitely need to work on my search engine prowess).

Jack

I got these HP-32E schematics from the HHC Handheld Computer Club London from Tony Duell. It is identical to the HP-38E, only the ROM contents differs.

                   

I hope this helps

Bernhard

That's one small step for a man - one giant leap for mankind.
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05-15-2017, 08:13 PM
Post: #5
RE: Schematics for HP38E
(05-15-2017 07:39 PM)PANAMATIK Wrote:  
(05-15-2017 06:22 PM)jwhsu Wrote:  Geoff,

Thanks. I think I saw this before, but promptly forgot about it (I definitely need to work on my search engine prowess).

Jack

I got these HP-32E schematics from the HHC Handheld Computer Club London from Tony Duell. It is identical to the HP-38E, only the ROM contents differs.



I hope this helps

Bernhard

This helps a lot. Thanks.

Jack
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05-15-2017, 09:28 PM
Post: #6
RE: Schematics for HP38E
Yes Tony's wiring diagrams are wonderful and I can only recommend that people join or visit HPCC:

I am fortunate as I travel and try to make the monthly meetings at imperial college. The resources, library, members including Tony Duells' special technical expertise are incredible.

HPCC
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05-16-2017, 07:41 AM
Post: #7
RE: Schematics for HP38E
(05-15-2017 04:41 PM)Geoff Quickfall Wrote:  Hello Jack!

Failure modes on the Spice series:
  • New battery design is larger then design used in calculator resulting in broken battery contact tabs.
  • Battery corrosion affecting battery compartment.
  • Corrosion affecting power flex ribbon.
  • Compression of foam compression substrate causing loose IC connections
  • Oxidation of foam compression substrate traces.
  • Various case cracks from bad attempts to separate shell or dropping. Weak plastics.
  • Display issues, especially on the floating IC version,

As far as wiring diagrams of the power supply, i direct you to this site, (Kees VanderSanden's excellent HP site) scroll down to find the spice series power supply schematic:

Power supply diagrams

Various articles for opening the shell and spice restorations.

Links at bottom of page

Cheers, Geoff





This is not directed at anyone in particular but web searches (google etc) are your friend.
Great!
Are somewhere anything similar about hp49g? And for hp27s?
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