Author Topic: EEVblog #582 - HP41CV Teardown (Read 34651 times)

DavidGoncalv · « **on:** February 17, 2014, 03:58:34 pm »

Awesome! I love HP calculators. RPN kicks the quizzes' ass!

Don't take the keyboard apart, but would it be possible to get the card reader mechanism and tear that down? That would be neat to see the strip go through and watch the data stream out.

FireBird · « **Reply #1 on:** February 17, 2014, 04:41:05 pm »

Dave, you've received a newer model. The older one had a separate processor board. See here for a comparison (you need to scroll down to the bottom). The additional board is the time module of the CX model.

nathanpc · « **Reply #2 on:** February 17, 2014, 05:05:13 pm »

Not worth damaging the calculator. Leave it intact.

If anyone wants the video (since it still haven't been posted to the blog webpage):

99tito99 · « **Reply #3 on:** February 17, 2014, 05:39:10 pm »

Don't go any further.

What's the purpose of the zig-zag trace next to the ASIC. Cheers, Mark

czdt8m · « **Reply #4 on:** February 17, 2014, 05:41:47 pm »

Don't tear this one apart any further.

One may pop up that is beyond repair. Worth waiting for that.

tszaboo · « **Reply #5 on:** February 17, 2014, 06:11:30 pm »

It is working, keep it that way.

Bored@Work · « **Reply #6 on:** February 17, 2014, 07:02:08 pm »

Didn't the submitter say this is a repaired/frankenstein unit assembled from several others?

hikariuk · « **Reply #7 on:** February 17, 2014, 07:18:25 pm »

I'd vote for waiting for a dead one to turn up on eBay.

Maxlor · « **Reply #8 on:** February 17, 2014, 07:42:54 pm »

I also say, don't destroy it.

But I would like to see what the rest looks like. Surely, someone has a 41CV that's already broken that they can send you?

bktemp · « **Reply #9 on:** February 17, 2014, 07:55:13 pm »

Interesting teardown, but I missed some comments on the odd pcb traces:
There is one meander shaped trace, but it does not make any sense to me in such a low frequency design.
One trace seems to be cut during design process but not removed.
And another trace ends without any connection.

Another interesting thing to note:
The caps are 105°C rated. This is quite rare in such a low power device.

JoannaK · « **Reply #10 on:** February 17, 2014, 07:58:30 pm »

Interesting machine.. Years back I took apart HP-28C model for repairs. Was real Pita to put back together since keyboard was fixed with those melted plastic rivets.

So.. IMHO Dave, keep it as it is, no point ripping working classic apart.. I'm sure there will be broken ones around for full smashup.

DavidGoncalv · « **Reply #11 on:** February 17, 2014, 08:05:54 pm »

This video made me pull out my HP-48G to run some of my favorite old programs. Alas!! Keys B-F no longer work! What will I do now? My programs!

I bought it when I started college with summer work money, and man that 'infinite stack' and the stack operations and little time-saving programs I wrote saved me so much time in quizzes and finals. Once I walked out after 15 minutes, my class mates thought I had quit and would get the worst score but they were so wrong - they all did so poorly the professor felt bad and let them try again. I got a B and sat out that 2nd quiz.

Cheated? No; if you can write a program to do the job against what might be thrown at you in a quiz, you've understood the problem and method of solution well enough. Also, I had a bad habit of forgetting every so often so I got to use a borrowed calc, a slide rule for giggles, or once just draw up a series of Smith chart plots and circle the solution location on the chart.

HP-ILnerd · « **Reply #12 on:** February 17, 2014, 08:26:43 pm »

As my first post, let me just vote: Preserved It!
I happen to own mint a C,CV, and CX plus a lot of HP-IL gear that they can run. Like a pair of 3468 multimeters
and the 3421 data acquistion module, etc. You could make a whole series on how cool and inter-operable this stuff
is.

They really don't make 'em like this any more.

SeanB · « **Reply #13 on:** February 17, 2014, 08:44:48 pm »

I have an old TI calculator that looks remarkably similar to the HP. Only issue is the keyboard is getting flaky, but other than that and some cosmetic damage it works fine. Looks like the HP battery packs would fit is as well.

Wytnucls · « **Reply #14 on:** February 17, 2014, 09:18:42 pm »

I have a TI58 and HP41C. The battery packs are totally different, unfortunately.
I also have two HP67s which can be completely dismantled, without destroying anything, if you're careful.

NickS · « **Reply #15 on:** February 17, 2014, 09:23:40 pm »

Quote from: bktemp on February 17, 2014, 07:55:13 pm

There is one meander shaped trace, but it does not make any sense to me in such a low frequency design.

I noticed that too. Seems to link between 2 caps but it looks really bizarre.

On the 'bottom' of the video there is also a cap, inductor, diode combo. Surely it doesn't have a switch mode regulator built in to the chip?

moemoe · « **Reply #16 on:** February 17, 2014, 09:30:38 pm »

It's teardown…MONDAY?

hans · « **Reply #17 on:** February 17, 2014, 11:27:47 pm »

I would leave it intact, as nice as it is now.

With a bit of googling, one can find the other side of the PCB rather easily:
http://www.keesvandersanden.nl/calculators/hp41cv_inside.php

And it's just a few dome buttons.

electronics man · « **Reply #18 on:** February 17, 2014, 11:37:46 pm »

Quote from: moemoe on February 17, 2014, 09:30:38 pm

It's teardown…MONDAY?

its tuesday in australia

Macbeth · « **Reply #19 on:** February 17, 2014, 11:47:19 pm »

Don't turn it on - TEAR IT APAAARRT! RIP IT TO BITS!

Too many HP fanboyz. Casio is where it's at wit' da kool kidz in town. Casio fx-82 is 4 life. It haz a ENG key, you know for real engineers, not paper plazzy degree engines.

Kill tha pretentious HP shit. Fo Real dood! fx-82 has an ENG key!

Ok, I will put the crack pipe down now...

Maxlor · « **Reply #20 on:** February 18, 2014, 12:40:24 am »

Quote from: Macbeth on February 17, 2014, 11:47:19 pm

Don't turn it on - TEAR IT APAAARRT! RIP IT TO BITS!

Too many HP fanboyz. Casio is where it's at wit' da kool kidz in town. Casio fx-82 is 4 life. It haz a ENG key, you know for real engineers, not paper plazzy degree engines.

Kill tha pretentious HP shit. Fo Real dood! fx-82 has an ENG key!

Ok, I will put the crack pipe down now...

The HP-35s has two ENG keys!

moemoe · « **Reply #21 on:** February 18, 2014, 08:05:47 am »

Quote from: electronics man on February 17, 2014, 11:37:46 pm

its tuesday in australia

I referred to youtube saying 'Published on 17 Feb 2014' even when country is set to Australia. But I wondered if I can't get it more accurate, so I digged into the yt rss feed:

Code: [Select]

[…]<pubDate>Mon, 17 Feb 2014 14:39:07 +0000</pubDate><atom:updated>2014-02-18T07:47:01.000Z</atom:updated><category domain='http://schemas.google.com/g/2005#kind'>http://gdata.youtube.com/schemas/2007#video</category><title>EEVblog #582 - HP41CV Calculator Teardown</title>[…]

And Sidney is UTC+11 => Mon, 17 Feb 2014 14:39:07+0000 becomes Tue, 18 Feb 2014 01:39:07+1100 and you're right, but only technically (as the 'felt day' turns over with sleep').

Kjelt · « **Reply #22 on:** February 18, 2014, 08:14:18 am »

Quote from: DavidGoncalv on February 17, 2014, 08:05:54 pm

This video made me pull out my HP-48G

Cheated? No; if you can write a program to do the job against what might be thrown at you in a quiz, you've understood the problem and method of solution well enough. Also, I had a bad habit of forgetting every so often so I got to use a borrowed calc, a slide rule for giggles, or once just draw up a series of Smith chart plots and circle the solution location on the chart.

Hmmm the 48 was not allowed in our courses since some smart ass had developed a program to communicate with ir to share the answers to other 48 owners. In your definition of cheating that would also be allowed

I still use mine on a weekly basis but mostly for standard calculations.

EEVblog · « **Reply #23 on:** February 18, 2014, 08:40:15 am »

Quote from: moemoe on February 18, 2014, 08:05:47 am

And Sidney is UTC+11 => Mon, 17 Feb 2014 14:39:07+0000 becomes Tue, 18 Feb 2014 01:39:07+1100 and you're right, but only technically (as the 'felt day' turns over with sleep').

For those who really care, I uploaded this Monday night about 11pm or something and went to bed, it was a several hour upload. I forgot to set to Private, so it got released as soon as it was uploaded.

lewis · « **Reply #24 on:** February 18, 2014, 09:20:34 am »

Quote from: moemoe on February 18, 2014, 08:05:47 am

Quote from: electronics man on February 17, 2014, 11:37:46 pm
its tuesday in australia

I referred to youtube saying 'Published on 17 Feb 2014' even when country is set to Australia. But I wondered if I can't get it more accurate, so I digged into the yt rss feed:
Code: [Select]
[…]<pubDate>Mon, 17 Feb 2014 14:39:07 +0000</pubDate><atom:updated>2014-02-18T07:47:01.000Z</atom:updated><category domain='http://schemas.google.com/g/2005#kind'>http://gdata.youtube.com/schemas/2007#video</category><title>EEVblog #582 - HP41CV Calculator Teardown</title>[…]
And Sidney is UTC+11 => Mon, 17 Feb 2014 14:39:07+0000 becomes Tue, 18 Feb 2014 01:39:07+1100 and you're right, but only technically (as the 'felt day' turns over with sleep').

Now that's commitment


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Author Topic: EEVblog #582 - HP41CV Teardown (Read 34651 times)

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