early HP-80 restoration and Tallnut HP-41C question.



#22

Hello all,

Just repaired a minty HP-80 with the metal strip below the red lens and above the numbers. I knew it was an early version with the metal strip but the lower label at the foot of the calculator stated "HEWLETT PACKARD 80" indicating a later case badging. Apparently this had never been opened as witnessed by the intact perfect label on the back.

HP-80:

Condition:

- back label intact(as new)
- functions on adapter only
- minty although very dusty
- lower back label states made in USA, patent pending contrary to
my my 1973 version which has the serial number embossed on the
lower label and made in Singapore.
- no serial number in the battery hatch as with the early versions
- the badge at the end says "HEWLETT PACKARD 80" which indicates
a later version.
- this has the metal strip between the lens and the keys above the
OFF/ON switch

Repair:
- clean all contacts
- clean case
- clean keys
- wash logic PCA and keyboard PCA

Upon removing the battery hatch to gain access to the screws I noticed no serial number in the battery hatch area (early versions) or on the bottom label between the lower feet (later versions) which is typical.

The ICs are all coded 72. The clincher is that I found a small sticky label under the PCA attached to the battery frame with the follwing number: 1247A43253. That makes it one of the first made according to the HP Museum and made prior to the release date in January, 1973!
Conclusion:

It would appear that this calculator with the serial number 1247Axxxxx was sent in for repair and a new back label attached as well as a new badging at the foot. The serial number was probably removed inside the hatch to indicate that this was repaired under warranty and the paper serial number added.

Any one else come across this type of serial number and rebadging after repair?

Also, when was the last year of the Tallnut key version of the HP 41C?

In any case, a lucky find, I think.

Cheers,Geoff


Edited: 5 Aug 2009, 5:32 p.m.


#23

There are people who know how to remove and replace the metal plate without leaving a trace. Also I have seen NOS back plates, as well as reproductions, on eBay - for those who can't.

It is possible you have a "Frankencalculator", one built up of spare parts. In my parts bin I even have a few of those rolled up paper serial number tags (including coincidentally, one with a 1247 datecode).


#24

I would normally agree accept that:


- the PCA date codes were correct.
- There was a dead LED block which I removed and replaced. The
code on the block was 1972.
- the case top is correct; i.e. missing the raised OFF/ON markings
the later ones have.
- the case top is correct; i.e. the metal top bar instead of
paint.

In other words, the only non-1972 stuff is the missing serial number in the battery hatch and the "HEWLETT PACKARD 80" at the foot. Both of these attached to the correct electronics, case bottom and case top.

The calculator was sold 'as is' for $35 dollars so all the work to make it a franken-calculator copy by smoothing out the original label or supplying a new one would appear to be for naught. Also why fake the serial number UNDER the PCA where it would not be seen except by a repair person.

One more point, not that I am trying to convince anyone, the logic PCA is older; 7202 versus 7210 found in my correctly serial numbered version stamped 1247-xxxxx.

I am aware of the ability to heat the label, remove it, remove the glue, then smooth it inside a vinyl card holder. This has the effect of saving the label for later use after a restoration. In fact there is a section on that in my book.

So, I am thinking that HP probably removed the metal serial number inside the battery hatch and replaced it with a type written serial number inside the calculator to indicate that it had been in for warranty work. Similar to a watch maker inscribing a code or date inside the back of the watch indicating work done and when.

The fact that you have some of the rolled up serial number tags suggests a few frankens around or some type of HP procedure to identify warranty repairs.

Just speculation at the moment.

Cheers, Geoff


#25

Geoff,

I own or have owned all 4 versions of the HP-80, to wit:

Version 1 - metal trim strip and "Hewlett Packard" on front label

Version 2 - metal trim strip and "Hewlett Packard 80" on front label

Version 3 - silver painted trim strip and "Hewlett Packard 80" on front label

Version 4 - silver painted trim strip and "Hewlett Packard 80" on front label and OFF / ON labels raised molded and not painted

Now, all 7 of these calculators have/had the serial number prefix 1247A. The only difference was in the following 5 digit sequence number. The version 1 is 07486 and the version 4s are 53367 and 58340. So this whole bit about the prefix being the year and week of manufacture is pretty much off base. I'd say the sequence number is the better indication of the manufacturing date.

The 43253 sequence number that is shown on the paper s/n in your photo is consistent with the numbers on my version 2s, which are 27000, 44973 and 50245.

I can believe that HP would replace the back label, but why bother with the front label, that does not have to be disturbed when opening.

Therefore, it appears to me that you have a version 2, not a version 1, and that nothing has been changed.

As far a Dan's comment regarding the aftermarket non-OEM back labels, I bought some of these, and they are all identifiable by their lack of the bottom text "MADE IN U.S.A., PATENT PENDING, 3.75V 500 MW". When I inquired with the seller of the label as to why he didn't include this, I was told that he didn't want to violate any laws, which helps prevent fakes from being made like the fake RED DOT that was recently on eBay.

Michael


#26

Spot on Michael,

Yep, with your numbers I have a two, three and four version.

Thanks for the insight.

Also, I was told that HP would swap out scratched labels for new labels. So although the series number puts it in version two, it would not be rare to find a version one series number with a version two badge. The example I was given was an HP-25 sent for service under warranty. It had a scratch on the badge at the foot of the calculator "HEWLETT PACKARD 25". It came back as a "HEWLETT PACKARD 25C" which it was not!

Also the inside typed serial number was a service item done after warranty.

Cheers, Geoff

p.s i had two HP-80 that did not work this morning and now have two fully functional nice looking ones going now. Granted one of them has an HP-55 LED block inside the display now instead of the dead segments on the original.

Edited: 6 Aug 2009, 3:08 a.m.

#27

The prefix is a "product revision" date.
For example, the 35s were made starting about 7215, still the "1143" (aka 7143) revision has been used for mass production. There even was a later 1146 revision (obviously long before public release), which hadn't been used. And remember: The 1143 represents the red dot and V2, even early Singapore units have a 1143 prefix.
So using the prefix is only a rough indicator of the manufacturing date, the postfix is a much better indicator, best would be to check the chip dates, which should be very close (2-4 weeks) to actual manufacturing date.


#28

Folks,

The prefix is not the week the calculator was manufactured. It is the week when the the last engineering change was made to this specific model.

The same prefix is then used on all subsequent production of this model, until another engineering change is implemented and the prefix changes once again.

In other words, a 1247 prefix means that the calculator includes a technical change that was first implemented in the 47th week of 1972. This particular calculator with the 1247 prefix may have been manufactured in the last month of 1972, or in 1973.

In theory, two calculators with the same prefix are completely identical when they are shipped from the factory, except for their serial numbers (the postfix). Of course this may no longer be true after repairs are made.

I hope this helps!

Joel Setton


#29

I accept the postfix/prefix argument as making the most sense. That is the first time I have read or seen this explanation but it would certainly explain the anomalies in case style, badge style and internal date codes.

However, here is a copy of the HP-41C manual, page 1-2 section 1.9:

You can see it does not mention revision dates, ALTHOUGH that could be implicit in the explanation as this manual was for staff and licensed repair shops. That is, Year of manufacture may actually refer to the chip set revision.

Any more thoughts before I commit information to the book!

Cheers, and thanks to all, Geoff

Edited: 6 Aug 2009, 12:46 p.m.


#30

The HP-97 Service Manual says the first 2 digits are the years since 1960, and the second 2 digits are the MONTH manufactured (pg 1.1).

Interesting! It appears the definition of the second 2 digits has changed from time to time.

For the earlier Classics, if the second 2 digits did in fact represent weeks, we should see examples from every week. But I would wager there are only a handful of variants.


#31

Quote:
For the earlier Classics, if the second 2 digits did in fact represent weeks, we should see examples from every week. But I would wager there are only a handful of variants.

I either own or can recall seeing HP-35 units with the following date codes:

1143
1230
1302
1346
Anybody have or know of others?


...

#32

Quote:
However, here is a copy of the HP-41C manual, page 1-2 section 1.9:

Geoff


That is the first time I've seen reference to UK manufactered machines (letter Q). I certainly don't have any Q calcs in my collection. As I live in the UK myself, it would be nice to acquire a UK built calc so...

Does anyone know which calcs had a UK production run please? And where was the UK factory and how long did it remain?

Thanks,

Mark


#33

Quote:


That is the first time I've seen reference to UK manufactered machines (letter Q). I certainly don't have any Q calcs in my collection. As I live in the UK myself, it would be nice to acquire a UK built calc so...

Does anyone know which calcs had a UK production run please? And where was the UK factory and how long did it remain?

Thanks,

Mark


I bought my calculator from a London store called Metyclean (don't know if they still exist). Going by the formula, my HP 41CX would have been manufactured in Singapore on 26 November 1983. (25 years and still calculating :-)

does anyone know what is HP policy with regards to production and sales of their calculators? I also have a 12C that was made in Malaysia which is where I live. Would HP sell in Malaysia a HP 12C that was made in USA or Brazil, for example? of course now, all HP calculators are made in China, AFAIK.

#34

It's possible that no calculators were made in the UK, but that some accessories (e.g., mains adapter) were.

#35

I think this may be a typo... IIRC, products manufactured in the United Kingdom used the letter U. HP had a factory in Scotland (South Queensferry) but it made telecom-testing instruments, I don't remember any calculators being produced in that facility.
Of course that was more than 25 years ago, I hope other HP old-timers have a better memory!

Joel Setton

#36

Quote:
The prefix is not the week the calculator was manufactured. It is the week when the the last engineering change was made to this specific model.

That was true of HP products other than calculators, and of early HP calculators. However, at some point they realized that the run rate for calculators was too high for that to work effectively, and they switched to using the actual manufacturing week for the prefix.

I'm not sure when that switch occurred, but I suspect that it was before or at the introduction of the Woodstock series.


#37

Hello and thanks all!

So nothing is as easy as it seems but this appears to be the timeline on the postfix/prefix deal:

- non calculators * revision date introduction/country/sequence number.
- early calculators * revision date introduction/country/sequence number.
- calculators post classic (around the woodstock era), with a change from month to week for the second digit pair
some where between HP-97 and HP-41C:
* manufacture date/country/sequence number.

Not that it is life or death but I want the introduction to be factual.

Cheers, Geoff

#38

Hi Geoff,

To further confuse the numbering. I have 2 HP80's with a lower serial# but with datecode 73 on the chips.

and the other one also with a metal rim under the lens:

Both do have a the small strip of paper with the serial number (equal to the one the calc itself).

Gr

Ronald


Edited: 6 Aug 2009, 2:48 p.m.


#39

This would simply mean that the chips were made in 1973, and the last engineering change to the calculator was in the 47th week of 1972. It makes sense, as the chips are obviously older than the calculator.

Joel Setton


#40

It does make sense.

Also, it's apparent that the "1247A" part of the serial number is pre-printed on the label, with only the last 5 digits imprinted.

If "1247" was in YYWW format, this would be a very cost-inefficient method of producing the labels.

#41

Quote:

Repair:
- clean all contacts
- clean case
- clean keys
- wash logic PCA and keyboard PCA


Hi Geoff,

A little OT, but what did you mean by "washing" the PCA's?

-- Dan


#42

When I restore a calculator, especially one with corrosion due to either battery leakage or out gassing I use a wash on the PCA.

a: To remove any vertigris (green or white precipitate) I rinse
(wash) the PCA with a mild vinegar solution followed by a
distilled water rinse and then 95% anhydrous ethanol (in Canada
thats known generically as 95% rubbing compound).

b: For stickey keys, a very dilute soap and water wash with water
rinse and anhydrous ethanol rinse

c: If there is no corrosion or stickey keys I use the water wash
followed by the anhydrous ethanol rinse.

Of course, sticky keys with corrosion would get both treatment a and b.

Heat staked keyboards with bouncy keys or even intermittant keys respond well to this and I have resurrected bad keyboards on:

Woodstocks
Coconuts
Voyagers
Pioneers
Stretch Pioneers

Of course the Classics and Spice keyboards can be diassembled and cleaned mechanically.

Cheers, Geoff


Edited: 10 Aug 2009, 9:23 p.m.


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