Some HP-50G Questions

[edryer]

Hi

Thought perhaps I'd use this to clear up some existing questions i had about the 50G.
Many thanks for any replies.

1.
When I am in the situation that I get the trying to recover memory dialogue, I press "A" for Yes and nothing happens... this is on both my 50G's, the key themselves are fine, but it requires multiple presses before (sometimes) it registers. No on the other hand is immediate.

2.
From what i can see of the HP-50G reset hole from disassembly videos it isn't simply a hole but seems to be a switch that touches the PCB contacts. Is this the case? It's just that I was rubbing down the back of one of my 50G's with toothpaste (minor abrasive to take out scratches) and some went in the reset hole.. peering in it now looks white.... does this actually reach the PCB or is it sealed between the "switch" and PCB?

3.
When I view objects that are Matrices used to be listed (if I recall) as MATRIX, they are now listed as ARRAY... what is the distinction because they are Matrices that I have created (and manipulate) but not sure why they are listed as arrays.

4.
What are the common failures of a 50G? Keyboard, LCD?

Realize quite a few questions and appreciate any responses!
Thanks
Ed Ryer

[berserkerbernhard]

Hi Ed.

Regarding question 1: What version of the firmware are you running? You could be experiencing a bug, I guess.

I have only had my 50G for about a year and I upgraded the firmware before serious use. So I never had the problem you have now.

The other questions is beyond me :-) Good luck finding an answer.

/Bernhard

[cdmackay]

(12-02-2018 03:04 PM)edryer Wrote:  1.
When I am in the situation that I get the trying to recover memory dialogue, I press "A" for Yes and nothing happens... this is on both my 50G's, the key themselves are fine, but it requires multiple presses before (sometimes) it registers. No on the other hand is immediate.

I have seen this on mine (latest firmware). I found that if Yes doesn't work, press another key first, then Yes, and it works.

[cyrille de brébisson]

Hello,


>1. Try to recover memory: A does not register
This is weird and I have never heard this... However, I might have some suggestions.
Trying to recover memory starts the calculator on a complex loop trying to locate valid objects in memory, figure out what objects belong to what and store all that back without overriding anything else...
If might be that it does take some time at the beginning, when you press A, to find the necessary space to generate enough free memory to run the code that displays the "recovering" message. But I am not certain on this one as I do not remember how the code was implemented (sys-RPL or ASM).


>2. reset hole
I do not remember the 50G mechanical. At one point this "hole" gave you access to a piece of bendable metal that was also the back EMC shield of the calculator. That grounded shield would bend down to the PCB and contact it when pressed. Closing the circuit and causing the reset. This explains the "shininess". But it might have been on the 49, not the 50. Other calcs like Prime use a switch.

>3.MATRIX, ve ARRAY...
From memory CAS objects are MATRIX (lists of lists internally), while ARRAY are SYS-RPL ARRAY type objects (which have fixed length sizes like complex or reals).

Cyrille

[Zaphod]

(12-03-2018 05:52 AM)cyrille de brébisson Wrote:  I do not remember the 50G mechanical. At one point this "hole" gave you access to a piece of bendable metal that was also the back EMC shield of the calculator. That grounded shield would bend down to the PCB and contact it when pressed. Closing the circuit and causing the reset. This explains the "shininess". But it might have been on the 49, not the 50. Other calcs like Prime use a switch.

Having just prodded one of my 50g's here, from the feel of it I agree the 50g uses a springy metal plate 'switch', not an actual tact switch.

[BartDB]

Question 4:

On the keyboard, broken or bent postunder the key has been reported:
50g post fixed with bead

The LCD has had reports of missing rows or columns:
50g LCD problems

I had the LCD problem on a 2006 model 50g. I purchased another in 2009 that has not had any problems so far. there were several reports on various forums around that time, but I have not seen any recently. Perhaps it was a problem with early units.
.

[edryer]

Thank you everyone for the kind responses, much appreciated.

The more I use this Calculator the more I am beginning to love it. In fact I was reading the HP-48 user manual from 1993 and found examples where the ENTER key was not used between arguments but simply the space key, everything was pushed on the stack when an operator was encountered.

So you could enter 10 space 10 space 10 X X SIN as a simple nonsensical example and obtain the result without using the ENTER key at all.. I find myself doing this quite often... simple but a revelation to me!

[grsbanks]

(12-03-2018 01:08 PM)edryer Wrote:  The more I use this Calculator the more I am beginning to love it.

That's the sign of a good calculator

The 50g is a versatile beast and I've always been a sucker for things RPL, so it's no small wonder that this one is high up on the list of my favourite machines of all time...

[rprosperi]

(12-03-2018 02:42 PM)grsbanks Wrote:  The 50g is a versatile beast and I've always been a sucker for things RPL, so it's no small wonder that this one is high up on the list of my favourite machines of all time...

Excellent news!! Someone more obsessed than I am... seeing this helps me to regain perspective.

But we are mere amateurs compared to Bill Butler in Montreal... at last count, he was nearing 50 x 50g machines.

[HP67]

(12-03-2018 02:42 PM)grsbanks Wrote:  

(12-03-2018 01:08 PM)edryer Wrote:  The more I use this Calculator the more I am beginning to love it.

That's the sign of a good calculator

The 50g is a versatile beast and I've always been a sucker for things RPL, so it's no small wonder that this one is high up on the list of my favourite machines of all time...

Wow! Am I seeing wrong or is there a version with a dark blue case? I have the Black and hideous light blue versions...

[grsbanks]

(12-04-2018 10:23 PM)HP67 Wrote:  Wow! Am I seeing wrong or is there a version with a dark blue case? I have the Black and hideous light blue versions...

It's just the lighting. Artificial above and daylight to the right. The daylight will always have a blue tinge to it compared to artificial.

I have 7x black and 1x clown vomit.

[pier4r]

8 x 50g!

Great! I hope they get used (or planned as backup!)

I have 4 (because first to compute, the second to develop, then a backup and a 3rd) and they feel a bit "a lot". I cannot imagine with 8! I would feel super guilty to not use them always!

I use the "compute 50g" at the moment mostly with multistopwatch. Since I started to take time of certain everyday tasks it is golden.

[HP67]

I have only two. Black and Blue

I wanted more, but I had to go through difficult trials to get the ones I have and I didn't think I could face it again

If there becomes a reasonably-priced source of NOS 50gs in the EU I'll grab a few more.

[edryer]

Thanks for the replies.

If it helps I spent MANY hours going over the HP48 usenet group archive, this forum via search, hundreds of Amazon reviews, and the Internet and my conclusion from hundreds of posts regarding reliability:

1. LCD lines seem to be limited to the first batches back in '06/'07 and even then they weren't a huge issue, after this no reports (or maybe one or two but may be because the Calculator manufacture was from this period).

2. Poor Keyboard seems a very rare issue. Some reports (and anger) stating the keyboard was "useless" and the key posts weak, however evidence doesn't bear this out as I can find only a handful (literally) of keyboard issues over ten years of postings. So my thoughts are the keyboard is of good quality overall and failures actually very rare. Obviously lessons were learned from the HP49 series.

3. One or two issues of poor solder joints (some work is done manually) - again this is a very rare issue and only a handful of posts. Failure then occurs often when the calculator is dropped (even from inches) and dislodges the joint. Still not statistically significant so it seems very much a non-issue.

So summary is Reliability is actually very good and arguably excellent.

Of course some may disagree ))

Ed


And the Reset hole is sealed internally by the mechanical reset mechanism ... anything going in doesn't reach the PCB, so my toothpaste "cleaning" issue wasn't an issue...

[TravisE]

(12-02-2018 06:40 PM)cdmackay Wrote:  

(12-02-2018 03:04 PM)edryer Wrote:  1.
When I am in the situation that I get the trying to recover memory dialogue, I press "A" for Yes and nothing happens... this is on both my 50G's, the key themselves are fine, but it requires multiple presses before (sometimes) it registers. No on the other hand is immediate.

I have seen this on mine (latest firmware). I found that if Yes doesn't work, press another key first, then Yes, and it works.

I can confirm that I've encountered this, and believe it or not, one of the little paper guides that shipped with one of the two HP 50g units I bought at some point even has a page acknowledging this behavior, stating that if the Yes button doesn't work to press some other key other than No first, then press Yes again.

It definitely smells like some kind of weird firmware bug that never got fixed. It beeps at you as if it thinks you're pressing an invalid key, until you press some other key first and try again. IIRC, it doesn't happen every time, but occasionally. I'm not sure exactly what triggers it.

[cdmackay]

(12-09-2018 12:35 AM)TravisE Wrote:  I can confirm that I've encountered this, and believe it or not, one of the little paper guides that shipped with one of the two HP 50g units I bought at some point even has a page acknowledging this behavior, stating that if the Yes button doesn't work to press some other key other than No first, then press Yes again.

It definitely smells like some kind of weird firmware bug that never got fixed. It beeps at you as if it thinks you're pressing an invalid key, until you press some other key first and try again. IIRC, it doesn't happen every time, but occasionally. I'm not sure exactly what triggers it.

The Quick Start Guide mentions it (see below) but for the NO key; on reflection, this is where I've seen it happen, too, I think, not the YES key. Perhaps it affects both.

Quote:QSG: To clear all your memory from RAM, press and hold the ON, F1, and F6 keys simultaneously. Release F6, then F1, then ON. After a beep, the screen displays, Try to Recover Memory?, with YES or NO menu key options. Press the NO menu key. If nothing happens, push any key. After the beep, press the NO menu key.

[grsbanks]

(12-08-2018 08:43 PM)edryer Wrote:  1. LCD lines seem to be limited to the first batches[…]

3. One or two issues of poor solder joints[…]

For what it's worth, I've only ever seen one HP 50g unit with a faulty LCD (in photos, not in real life) and read about one with bad solder joints.

Given the popularity of the 50g, I think that's pretty good reliability. Nearly all of the other problems I've read about are down to user mistreatment, usually dropping the thing or forgetting it in a drawer with the batteries installed and leaking all over the contacts.

[edryer]

Quote:For what it's worth, I've only ever seen one HP 50g unit with a faulty LCD (in photos, not in real life) and read about one with bad solder joints.

Yes. My (very limited experience, have only two units!) conclusion is that the HP-50G is actually so far a very reliable device and I have also only seen the same posts as you probably.

Amazon (US) rate it 4.4 with 864 reviews (90% 4 or 5 star) with the low star reviews often given it due to it being "overly complex" (!!!!) - only one or two on QC issues.

The TI-89 Titanium rating 4.2 - ‎1,049 reviews - itself a very reliable device, scores slightly lower.

My experience of Amazon is that if an electronic product has any even minor QC issue there will be a sufficient number of 1 star "angry" ratings immediately noticeable.

----

Another interesting issue:

I always had a Samsung Micro SD Card (2GB) with a holder in the HP-50G, and when powering on there was always a three second or so delay before the LCD came alive and the Calculator functional. I thought this was normal...

I then managed to buy a 2GB "pure" SDHC card and used it in the slot - imagine my surprise when the Calculator started instantly!

It seems when using (at least in my case) Micro SD Cards + Adapter in the 50G there is a long delay to startup not seen with a straight SDHC card.

Both cards were formatted and "empty" to test.

[cdmackay]

(12-09-2018 02:04 PM)edryer Wrote:  Another interesting issue:

I always had a Samsung Micro SD Card (2GB) with a holder in the HP-50G, and when powering on there was always a three second or so delay before the LCD came alive and the Calculator functional. I thought this was normal...

I then managed to buy a 2GB "pure" SDHC card and used it in the slot - imagine my surprise when the Calculator started instantly!

It seems when using (at least in my case) Micro SD Cards + Adapter in the 50G there is a long delay to startup not seen with a straight SDHC card.

Both cards were formatted and "empty" to test.

There are some long threads on this, but I remember reading that one of the key points is to format the card as FAT16. If formatted FAT32 (which might be the default, for a 2GB card), it will take longer to read at startup.

My notes say:

• FAT16 is required for (re)flashing firmware, and recommended for startup speed
• 50g itself can only format to 1GB, but will happily use a 2GB card if formatted on a PC (FAT16)
• 50g will only use the first partition of a multi-partition card
• don't overfill root (or indeed any) directory, organise into sub-dirs, for better performance

I use a 2GB SD card, formatted to FAT16 (on a Mac). I don't have any noticeable delay when pressing ON (although I don't have much on the card).

Edit: I think microSD cards are always going to be slower than an otherwise equivalent SD card, as you say.

[HP67]

It seems to me there should be no technical difference of cards based on physical format alone. If you compare specs on both you should find the difference.

All the Samsung cards I have bought have been dog slow. And there is also the problem of counterfeit cards of all kinds, which makes it hard to verify the ratings that should apply to the card actually do.