Problems with 34C



#21

Hi there

I purchased a HP34C from ebay and the listing stated "battery terminal has corrosion" but I took a chance (cost me $125 with case but with no charger and no battery pack here in the UK).

I inserted two AA Alkalines and great... the calculator works and passes self test and retains memory.

However the contacts on the battery pack were pretty messy but I managed to scrape off most of the residue which seemed to work its way also inside the calculator.

My question is? Will the remaining residue cause a problem in the future, some of it is inside and therefore I haven't been able to clean it (but can see it through the charging port).

The calculator also has a small crack near one of the screws... I assume this is due to the "slight" stretch when using alkalines?

Thanks for any advice!

According to the serial number it is a week 45 and year 1979 model.
I think it is the "solderless" design.


#22

Write Randy at FixThatCalc.com and see if he can help. He considers Spice repairs on a case by case basis.

If things are working and you work to prevent further corrosion/leakage from newer batteries, I think you will be okay.

Using standard size AA cells cares the risk of straining the compartment and even pressing and breaking the contacts. Indeed, I got my 33C like this, but there was enough of a nub to make contact. To keep the pressure to a minimum I pack the cells in with the thinnest bit of foil jumper I can--just enough to maintain snug contact. So far, I use NiMH batteries with apparent impunity, frequently swap them.

I have a 33C and 34C. The latter is of course my favourite.

Les


#23

Thanks Les.

I also use a thin foil like connector which allows the batteries to be inserted without undue stress to the calculator connectors (the actual stress seems minimal actually).

As for the crack. I will place a speck of glue in this to "bridge the small gap" left by the "stretching" of the calculator.

I was surprised as I have read many times the build on the spices were substandard, however, it subjectively seems "stronger" than my old 41C, even the key clicks are a lot firmer (although I think later soldered versions of the 34C had a lighter more 41C like keyboard).

Regards from the UK
Ed


#24

Quote:
I was surprised as I have read many times the build on the spices were substandard, however, it subjectively seems "stronger" than my old 41C, even the key clicks are a lot firmer
For sure you'll bash me for the following, but IMHO the build quality of the 41C's *housing* was even worse. Spice housings have a suboptimal battery door, which was solved better with the 41C, but the connection of the bottom and top halves of the calc is not very solid in the 41C. Nothing compares to Woodstocks when it comes to rock solid mechanical construction of classical calcs.

Ceterum censeo: HP, launch a 43s.

Walter


#25

Quote:

For sure you'll bash me for the following, but IMHO the build quality of the 41C's *housing* was even worse. Spice housings have a suboptimal battery door, which was solved better with the 41C, but the connection of the bottom and top halves of the calc is not very solid in the 41C. Nothing compares to Woodstocks when it comes to rock solid mechanical construction of classical calcs.

Ceterum censeo: HP, launch a 43s.

Walter


I agree. The 41C housing is surely not as solid as the spice series (or at least my 34C). Nearly, but not quite. I also agree about the battery door - much better on the 41C.

Its a funny thing that the spices have a reputation for battery corrosion of terminals.. I saw the same thing on a 48GX a few years ago that had been in storage.. I'm suspicious about any "old" calculator now in that respect!


#26

Quote:
Its a funny thing that the spices have a reputation for battery corrosion of terminals.. I saw the same thing on a 48GX a few years ago that had been in storage.. I'm suspicious about any "old" calculator now in that respect!

That's not the fault of the calculator, it's the fault of the batteries, em, the users who forget the batteries therein.
#27

Hi Ed,

Quote:
I was surprised as I have read many times the build on the spices were substandard, however, it subjectively seems "stronger" than my old 41C, even the key clicks are a lot firmer (although I think later soldered versions of the 34C had a lighter more 41C like keyboard).

I am fortunate enough to have both types of 34C's in my collection.
The earlier unsoldered models contained a substantail metal plate which provided a rigid surface against which to clamp the IC's to the flexible circuit board. Another defining characteristic of these "solderless" models is relatively long key travel and quite heavy detents, due to the use of plastic snap domes under the keys. Reliability issues caused HP to switch to "conventional" construction (soldered PCB and metal snap domes) later on.


Concerning the corrosion on the battery / charger traces inside the machine, I had the same issue on my late model 34C. I applied a little shot of "DeOxit" (available at electronics stores) to the affected area, and have had no problems since.

Best regards, Hal

#28

Quote:
According to the serial number it is a week 45 and year 1979 model.
I think it is the "solderless" design.

What is the significance of the solderless design please? Is it something to be wary of when collecting, like the dusty displays on some Pioneers?

Regarding the discussion over construction quality, I only have one from that series - a 31E - and it feels very solid in the hand. The keys are easily the "heaviest" I have encountered and need the firmest push, too hard for fast use. Oh, and I think the battery cover is loose and the charger connector definitely has a soft mating.

Not seeing many Spices on ebay these days...

Mark


#29

From memory I think the main problem with the solderless units is oxidisation on the chip pins which causes intermittent connection problems. On the other hand the solderless design makes them easier to service (if you have spare chips). Also I think the keyboards are of different construction and have a different feel.

If you do an archive search around 2003 for posts by Norm, NH or Captain Zener you should find lots of good information about the 34C and some good laughs.

Red LEDS forever!

Edit > ps Norm's HP-34C BETTER THAN S*X is classic!

Edited: 21 Oct 2008, 3:36 p.m.


#30

Thanks James - I'll do some searching for those names (if I can work out how to use the forum search engine! I really find that confusing unfortunately and it doesn't seem to search multiple archives at a time which makes it slow). Hopefully there is some way of telling from serial numbers or other indicators which is solderless or not.

Mark


#31

Yes, it would be great if one could search all the archives in one go. Norm (and his alter ego Captain Zener) was a real enthusiast for the HP34C and there were some good discussions from him and Luiz on the 34C and how to look after them.

I believe that the solderless units are heavier than the soldered ones. The 34C specs in the Museum give the weight as between 6oz and 8oz with earlier models weighing about 1.5 oz more than later. Mine tops out at 6.5oz so I'm hoping that it's soldered but haven't been brave enough to open it up yet - from what I've read there is quite an art to opening the Spice cases so I've buried my head in the sand so far.


#32

http://www.voidware.com/calcs/spicerepair.htm

I own a 33E and a 32E unit that I recently purchased for an exam that did not allow programmable calculators (this is a great little non-programmable scientific/stats calculator by the way). I successfully opened and inserted some foam padding to stiffen the keys of the 33E machine using the procedure shown at the link above and it is impossible to tell that it has ever been opened. It is not that difficult at all - believe me if I can do it, anybody can.
Good luck!

As it turned out, the PMP exam did not allow any calculators at all - except for a cheap 4-banger that they furnished.
Jeff Kearns


#33

Hi Jeff

Thanks for the link, I'll get my courage up and give it a go, soon!

James

#34

RE: The voidware how-to-repair photos.

Avoid at all costs the "scraping the oxide off the power switch". It's not oxidation, it's wear. Scraping only makes matters worse. Clean well with a cotton swab and isopropyl then lubricate with plastic safe white grease that contains teflon. Anything more than that and you'll be looking for a parts donor for a replacement keyboard.


#35

I once some years back got my 34C to work for a little while more not by scraping the switch contacts, but gently rubbing with an eraser. The rubber should not remove any more metal, but may remove any dirt not loose enough to be gently blown off.

(Nowadays, I'm not nearly as brave opening up a Spice case.)

#36

Randy, thanks for the advice. It's duly noted for when (if) i finally open her up.

#37

Hi James,

Quote:
Norm's HP-34C BETTER THAN S*X is classic!

Didn't know this - appeared right before I joined the forum - thanks for pointing to this great little piece of literature :)

Ceterum censeo: HP, launch a 43s.

Walter


#38

Hi Walter

Glad you like it - it always cheers me up!

HP Calculator Music: John Denver, Paul Simon is good as well (and also mentions the 34C so hopefully not too off topic for this thread!)

James

#39

If you want a manual (hardcopy) I have a spare 'copy' that I could send to you if you are in the UK.

My HP34C works fine with Lithium AA cells and it is a very capable machine.

Mike T.

Edited: 21 Oct 2008, 4:48 p.m.


#40

Mike - many thanks I hace sent you a message!

Walter B- yes I appreciate the corrosion is the batteries fault.. rather than the calculator :) however since seeing the 48GX with a mildly corrosive terminal it made me realize no matter how "new" the calculator its always advisable to ask whether the terminals are free of corrosion. Many thanks!


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