HP-32E Advanced Scientific Calculator - my first Spice machine
11-11-2016, 09:42 PM
Post: #1
 jebem Senior Member Posts: 1,343 Joined: Feb 2014
HP-32E Advanced Scientific Calculator - my first Spice machine
Yesterday I got this machine from a local seller.

Like many of these kind of machines, this one also has corroded battery terminals caused by the Ni-Cd batteries forgotten inside the machine for years.

Although when I applied an external 3-Volt power supply i got a satisfying normal initialization showing "0.0000" in the LED display.
Tried the self test and nothing happened. The Enter key is not working at all.

Still I decided to buy it and see if I can repair it.

These pictures are from the seller advert.
As Bob mentioned elsewhere in another post, this model would not be sold in a hard case like this one.

The guilty component.

After opening the machine I found the missing battery connector lose inside.

One good thing: The machine was never opened before, although someone may have tried to undo the two screws a little but quit after realizing that it was "impossible" to open it without breaking it.

That eventual frustrated tentative have left marks on the plastic threaded posts where the two screws go. One post is cracked in three places but can easily be repaired.

And the usual look after a battery leak.
I was lucky because after cleaning all the battery leakage components I found out that the power supply flat cable didn't suffer enough corrosion to break.

The third IC is not installed. A few reports I have been reading mention that some 32E machines came with the middle position filled in.
This is what this machine have installed:
1MA4-0003 DIP40 processor
1MA3-0004 DIP8 memory
1MA1-0009 DIP8 memory

General parts after cleaning.

Power supply.
Great information with schematics here from Kees.

Thanks to Geoff Quickfall, Kees, Karl Schneider and many others that have been posting here and elsewhere sharing their experiences and knowledge.

(Continued)

Jose Mesquita

11-11-2016, 09:58 PM
Post: #2
 jebem Senior Member Posts: 1,343 Joined: Feb 2014
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
Display and solder-less sandwiched PCA.
Component and keyboard sides.

The keyboard uses three plastic layers:

- Top layer – Five conductive trace lines with embedded clickable dome contacts and double paths for redundancy.

- Middle layer – Isolates top from bottom conductive trace lines

- Bottom layer – Part of the flex PCB with seven conductive trace lines with fixed base dome contacts and five additional trace lines to interconnect (via solder joints) with the five lines from the top layer.

The flex PCB is folded around a rigid metal/foam frame where one side support the keyboard and the other receives the IC’s and power supply interconnection using a solder-less sandwich approach.
More details here.

I found out that the top flex layer is not glued, so it is easy to carefully lift it to see what is underneath and do some maintenance if required.

Here we can see the top flex PCB metallized traces and dome.

A small partial schematics of the keyboard and display, obtained by direct observation.

To analyze the ENTER key issue, I have used a ohmmeter to check continuity of some of the working keys.
A good contact gives zero Ohm.

The inoperative ENTER key was giving infinity resistance.
Initially I was afraid that the trace lines were broken because the ENTER key is not in series with any other key in the top layer flex PCB.

But then HP have designed the circuit with full redundancy paths, so the probable cause would be something else.

And after lifting the top layer flex PCB I saw the cause: the base contact at the bottom flex PCB was heavily oxidized at the point of contact of the upper metal contact embedded in the plastic dome.
After cleaning it the good continuity was restored.

Next steps involves the battery compartment connectors repair, fixing the plastic posts, and then start the reassembling for testing.

Jose Mesquita

11-11-2016, 10:06 PM
Post: #3
 d b Senior Member Posts: 489 Joined: Dec 2013
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
Great find Jebem.
I found a 38c last Sunday for $12 at the mercado de pulgas. It was in approximately the same condition as yours (minus all your cool accessories) but the batteries had spewed so thoroughly that I had to soak it in vinegar to get the door off. It's cleaned and neutralized now, waiting till I have the interest to make a battery clip. 11-12-2016, 09:42 PM Post: #4  jebem Senior Member Posts: 1,343 Joined: Feb 2014 RE: HP-32E Advanced Scientific Calculator - my first Spice machine (11-11-2016 10:06 PM)Den Belillo (Martinez Ca.) Wrote: I found a 38c last Sunday for$12 at the mercado de pulgas. It was in approximately the same condition as yours (minus all your cool accessories) but the batteries had spewed so thoroughly that I had to soak it in vinegar to get the door off. It's cleaned and neutralized now, waiting till I have the interest to make a battery clip.

$12USD. Now, that's a bargain! I can't find HP machines here for that price range, but our market is very small when compared to USA. Well, I have paid well over that price. The seller was asking 60 Euro, but he eventually accepted 40 Euro. I have used vinegar as well on this 32E and later have washed it in warm water and hand dish wash detergent. Jose Mesquita RadioMuseum.org member 11-12-2016, 10:12 PM Post: #5  d b Senior Member Posts: 489 Joined: Dec 2013 RE: HP-32E Advanced Scientific Calculator - my first Spice machine (11-12-2016 09:42 PM)jebem Wrote: (11-11-2016 10:06 PM)Den Belillo (Martinez Ca.) Wrote: I found a 38c last Sunday for$12 at the mercado de pulgas. It was in approximately the same condition as yours (minus all your cool accessories) but the batteries had spewed so thoroughly that I had to soak it in vinegar to get the door off. It's cleaned and neutralized now, waiting till I have the interest to make a battery clip.

\$12USD. Now, that's a bargain! I can't find HP machines here for that price range, but our market is very small when compared to USA.

Well, I have paid well over that price. The seller was asking 60 Euro, but he eventually accepted 40 Euro.
I have used vinegar as well on this 32E and later have washed it in warm water and hand dish wash detergent.

A good rinse at the end is important. Some people even use distilled water.
We have more cheap broken HPs here because you guys took better care of yours over there.
11-12-2016, 10:48 PM
Post: #6
 jebem Senior Member Posts: 1,343 Joined: Feb 2014
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
This is time to assemble this machine, even if I have no time now to make new custom battery clips.

Soldering new clips is not a good idea as it will isolate the connection to the flat cable traces in the back.
However that's what I have done to be able to test the calculator.
Of course after all this heat I got an isolated connector with about 18 Ohm resistance.
So I have used an old trick on these cases: have soldered a thin wire between the battery connector and the flat cable copper trace.

Power supply back in its place in the plastic frame.
IC's lay down having pin1 pointing to the power supply.

Now it is the flex PCB assembly turn.
The brackets are prepared to be inserted on both sides.

A small detail concerning grounding.
This design uses positive common ground circuit.
Once the right side bracket is inserted (having the keyboard facing up), when the power switch is ON the battery positive side is connected to the metal frame.

Cleaning the PCB traces is essential for good operation. I use isopropyl alcohol with good results.

And at last the big moment. Testing the work done.
I used a set of two 1.5V AA depleted batteries for a total of around 2.5V when loaded.

In order to be able to test the PCA out of the case, I had to solder three thin wires to bypass the power switch. Used wrapping wire AWG33. But the thinner the better.
A low melting point solder is essential here.
Adjust your soldering station to an adequate temperature. Too low and the flex PCB will be destroyed as it will require more time to solder.For this job I have used a regular Antex CS18 18Watt thin tip soldering iron and leaded thin solder "Wonder Solder" by TRT.

This is a simple procedure but requires special attention when soldering the wires because the flex plastic material is extremely fragile and seems to have a low melting point.
Therefore tinning of the flex traces is not recommended. I have just tin the thin wires and then while heating the wire just pressed it briefly (less than a second) against the flex traces using the soldering iron tip.

After a couple of minutes, I got the battery low indicator.
At the time the batteries had 2.30V.

Initial current consumption of 103mA after power on.

The self test (STO followed by ENTER) passed without errors on every check I have done.
All LED display segments lit resulted in around 202mA.
I have no references on current consumption on these HP models, but it seems a little too high even for this design and technology.
Perhaps the DC-DC converter power supply needs new capacitors, but I will leave it as it is for now.

(Continued)

Jose Mesquita

11-12-2016, 10:56 PM (This post was last modified: 11-12-2016 11:15 PM by jebem.)
Post: #7
 jebem Senior Member Posts: 1,343 Joined: Feb 2014
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
For now the calculator will be assembled having one battery connector soldered.
I will leave the battery connectors fix for another time.

A small parenthesis to comment on the nice injection molded keys.
They don't make it like this anymore.

Details of the power switch.

Keys deposited in the front case frame.

And the PCA inserted into the front case.
Besides being a solderless design, this calculator is screwless design too (well, it uses just two screws to close the back cover.

Detail of the back cover latch at the front side.
This latch is the responsible for the notorious hard/delicate (chose your option) operation required to open this calculator.

The original battery was cleaned to remove all the leaked electrolytes and was inserted to make sure the soldered battery connector is mechanically functional.

I have ordered a new set of batteries with solder tags from TAS. Then a small surgery will be required to replace the old with the new ones. Waiting for arrival now.

(Continued)

Jose Mesquita

11-12-2016, 11:02 PM (This post was last modified: 11-17-2016 10:59 AM by jebem.)
Post: #8
 jebem Senior Member Posts: 1,343 Joined: Feb 2014
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
Just for fun, tried to get SQRT(-2). Got an Error 0.

And again the self test passing with flying colors.

The AC battery charger i got with this machine has the p/n 82090B.
The battery that came with this machine has the p/n 1420-0313, Made in Japan
(Edited to correct the part number. Originally typed as 1420-0813, but closer inspection of the battery pack label gives me the impression that the correct digit is "3" and not a "8".)

For those ones who, like me, never saw it before, here is the self test procedure in a video.
The ROM checkum and RAM ability to write and read is covered during the self test. Deed dive from guru Eric Smith ( brouhaha) here.

Jose Mesquita

11-12-2016, 11:02 PM
Post: #9
 Harald Senior Member Posts: 760 Joined: Dec 2013
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
Very nicely documemted! Thanks for sharing!
11-12-2016, 11:20 PM
Post: #10
 jebem Senior Member Posts: 1,343 Joined: Feb 2014
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
(11-12-2016 11:02 PM)Harald Wrote:  Very nicely documented! Thanks for sharing!

Thank you, Harald.
Cheers!

Jose Mesquita

11-12-2016, 11:47 PM
Post: #11
 Harald Senior Member Posts: 760 Joined: Dec 2013
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
(11-12-2016 11:20 PM)jebem Wrote:
(11-12-2016 11:02 PM)Harald Wrote:  Very nicely documented! Thanks for sharing!

Thank you, Harald.
Cheers!

Thank you, too, José !

Cheers,
Harald
11-14-2016, 02:50 PM (This post was last modified: 11-17-2016 08:39 AM by jebem.)
Post: #12
 jebem Senior Member Posts: 1,343 Joined: Feb 2014
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
Battery pack replacement

I received a new set of batteries from TAS and it are now installed in the battery compartment.

Instead of the original Ni-Cd based technology, I have used the Texcus Ni-MH type Mignon AA HR6 1.2Volt 2100mAh with solder tags.

I have soldered the tags on one side to configure the two cells in series and have removed the tags on the other side (facing the battery connector clips).

Because these batteries are a bit longer than the original ones, there is no need to use the original plastic frame that would add at least 1mm to the overall length.
The new batteries overall length is 0.5mm longer than the original battery pack.

The battery cover fits nicely as these new cells diameter is only 0.5mm larger than the original battery pack size.

These batteries are sold with near full charge, so I set the calculator in test mode to have all segments lit and left the machine powered on.
Seven hours has passed now and it is operating normally with no sign of battery low annunciator.

Probably these batteries can give a maximum continuous operation for around 10 hours (2100mAh Ni-MH capacity / 200mA consumption with all digits lit).

According to the HP owners guide, the original battery pack would run for around 3 hours of continuous operation.
EDIT:
"A quick calculation shows that that claim is correct (700mAh Ni-Cd capacity / 200mA = 3,5hours)."
As noted by Dieter (see below), 700mAh AA batteries were not available at the time the Spices were released. Probably the original battery pack would have 450mAh capacity.

The calculator running in full autonomous and portable mode.

(the end)

Jose Mesquita

11-15-2016, 09:57 PM
Post: #13
 aurelio Senior Member Posts: 601 Joined: Dec 2013
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
...aaarghhhhhhh... Il lost this your post.
What a great job
11-15-2016, 10:51 PM
Post: #14
 Dieter Senior Member Posts: 2,397 Joined: Dec 2013
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
(11-14-2016 02:50 PM)jebem Wrote:  Instead of the original Ni-Cd based technology, I have used the Texcus Ni-MH type Mignon AA HR6 1.2Volt 2100mAh with solder tags.

Sounds like a common low self-discharge type.

(11-14-2016 02:50 PM)jebem Wrote:  I have soldered the tags on one side to configure the two cells in series and have removed the tags on the other side (facing the battery connector clips).

FTR: there are also battery packs with two cells already welded together.

(11-14-2016 02:50 PM)jebem Wrote:  According to the HP owners guide, the original battery pack would run for around 3 hours of continuous operation.
A quick calculation shows that that claim is correct (700mAh Ni-Cd capacity / 200mA = 3,5hours).

Back in the days of the Spices series, around 1980, there were no 700 mAh NiCds. The regular capacity was 450 mAh, later maybe up to 500 mAh. So with a decent 2000 mAh battery you now can expect 4x the original operating time.

Dieter
11-16-2016, 12:10 AM
Post: #15
 jebem Senior Member Posts: 1,343 Joined: Feb 2014
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
(11-15-2016 10:51 PM)Dieter Wrote:  Back in the days of the Spices series, around 1980, there were no 700 mAh NiCds. The regular capacity was 450 mAh, later maybe up to 500 mAh. So with a decent 2000 mAh battery you now can expect 4x the original operating time.

Hi Dieter,
Well, I couldn't find information on what battery capacity HP used on the Spices, so I assumed it were the common 700mAh considering that my calculator was made in 1980 week 34.

I worked with AA NiCd cells in early 80's having 700mAh for memory backup systems in mini computers, and in mid 80's we had 1000mAh manufactured for professional applications, for example by Panasonic.

But on second thought the Spice design began before 1980 and they have used the existing 70's technology, so most probably they have used the 450mAh models.

Cheers,
Jose

Jose Mesquita

11-16-2016, 11:59 AM
Post: #16
 jebem Senior Member Posts: 1,343 Joined: Feb 2014
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
(11-16-2016 12:10 AM)jebem Wrote:
(11-15-2016 10:51 PM)Dieter Wrote:  Back in the days of the Spices series, around 1980, there were no 700 mAh NiCds. The regular capacity was 450 mAh, later maybe up to 500 mAh. So with a decent 2000 mAh battery you now can expect 4x the original operating time.

Hi Dieter,
Well, I couldn't find information on what battery capacity HP used on the Spices, so I assumed it were the common 700mAh considering that my calculator was made in 1980 week 34.

I worked with AA NiCd cells in early 80's having 700mAh for memory backup systems in mini computers, and in mid 80's we had 1000mAh manufactured for professional applications, for example by Panasonic.

But on second thought the Spice design began before 1980 and they have used the existing 70's technology, so most probably they have used the 450mAh models.

Cheers,
Jose

Hi again, Dieter,

I repeated the test run with the new 2000mAh batteries and consistently I got a little above 12 hours of continuous run having all the display segments lit.

This is about four times more autonomy than using the original batteries as you have predicted.

Cheers,
Jose

Jose Mesquita

11-16-2016, 12:05 PM
Post: #17
 jebem Senior Member Posts: 1,343 Joined: Feb 2014
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
(11-15-2016 09:57 PM)aurelio Wrote:  ...aaarghhhhhhh... Il lost this your post.
What a great job

Hi, Aurelio, thanks for your kind words, but as you see, errare humanum est!

By the way, and totally off topic, when you have the time, please share what you have done on yours HP-41 machines concerning the keys replacement.
Did you remove the keyboard PCB by cutting those plastic rivets in order to reach the actual keys?

Jose Mesquita

11-16-2016, 02:08 PM
Post: #18
 Dieter Senior Member Posts: 2,397 Joined: Dec 2013
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
(11-16-2016 12:10 AM)jebem Wrote:  Well, I couldn't find information on what battery capacity HP used on the Spices, so I assumed it were the common 700mAh considering that my calculator was made in 1980 week 34.

I do not think that 700 mAh NiCds were common those days.
You said:

(11-16-2016 12:10 AM)jebem Wrote:  I worked with AA NiCd cells in early 80's having 700mAh for memory backup systems in mini computers, and in mid 80's we had 1000mAh manufactured for professional applications, for example by Panasonic.

Hmm... I got Panasonic Industrial catalogues from 1990 (!) with their complete NiCd range. Their top-of the line AA product was the P100AAS with 1000 mAh. But this type was not available in the early Eighties. In 1985, years after the Spice production had ended, 600 or maybe 700 mAh was all you could get, both from Panasonic and from Sanyo. At least to the best of my knowledge. That's why I wonder what batteries you may refer to. And that's why I hope I may humbly ask if you're sure it was 1980 and not 1990 ?-)

Dieter
11-16-2016, 03:53 PM
Post: #19
 jebem Senior Member Posts: 1,343 Joined: Feb 2014
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
(11-16-2016 02:08 PM)Dieter Wrote:
(11-16-2016 12:10 AM)jebem Wrote:  Well, I couldn't find information on what battery capacity HP used on the Spices, so I assumed it were the common 700mAh considering that my calculator was made in 1980 week 34.

I do not think that 700 mAh NiCds were common those days.
You said:

(11-16-2016 12:10 AM)jebem Wrote:  I worked with AA NiCd cells in early 80's having 700mAh for memory backup systems in mini computers, and in mid 80's we had 1000mAh manufactured for professional applications, for example by Panasonic.

Hmm... I got Panasonic Industrial catalogues from 1990 (!) with their complete NiCd range. Their top-of the line AA product was the P100AAS with 1000 mAh. But this type was not available in the early Eighties. In 1985, years after the Spice production had ended, 600 or maybe 700 mAh was all you could get, both from Panasonic and from Sanyo. At least to the best of my knowledge. That's why I wonder what batteries you may refer to. And that's why I hope I may humbly ask if you're sure it was 1980 and not 1990 ?-)

Dieter

Hi, Dieter,

It was early 80's. We used them on our DataSaab D16 systems, despite it was a custom design with solder tags, not a standard AA size if I remember well. Can't really be sure after all these years.

A quick search shows https://www.panasonic.com/global/consume...story.html info that you probably saw already, although these mid 80's Panasonic 1000mAh were not standard AA in size:
In June 1985, the first SM30 model P-100AAS entered mass production, an AA-long-type (diameter 14.5 mm x height 65 mm) with a capacity of 1,000 mAh­―30 % more than existing types with a nominal capacity of 750 mAh.

But we agree that 700mAh were common in mid 80's.
As you mentioned before, the 32E could not use them as it finished production in 1983.

Thanks for the correction.

Cheers,
Jose

Jose Mesquita

11-16-2016, 10:10 PM
Post: #20
 Dieter Senior Member Posts: 2,397 Joined: Dec 2013
RE: HP-32E Advanced Scientific Calculator - my first Spice machine
(11-16-2016 03:53 PM)jebem Wrote:  A quick search shows https://www.panasonic.com/global/consume...story.html info that you probably saw already, although these mid 80's Panasonic 1000mAh were not standard AA in size:
In June 1985, the first SM30 model P-100AAS entered mass production, an AA-long-type (diameter 14.5 mm x height 65 mm) with a capacity of 1,000 mAh­―30 % more than existing types with a nominal capacity of 750 mAh.

That's not AA, that's 5/4 AA. Of course this bigger size allowed more capacity. The mentioned 750 mAh rating most probably also refers to 5/4 AA. The P100AAS I referred to was a regular AA size battery.

Another alternative was size A (not available as a regular consumer battery), which is only 2 mm thicker than AA but it made 1000 mAh possible long before it was available in AA size.

(11-16-2016 03:53 PM)jebem Wrote:  But we agree that 700mAh were common in mid 80's.

Let's say: the late Eighties. Around that time (1990) the first NiMH batteries became available. At that time – in regular AA size – with capacities between 900 and 1200 mAh, which was 1,5...2x the usual NiCd rating.

Dieter
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