HP-67 stuck in scientific (DSP 0) mode

[tribidouille]

Hello members,

I might have done a unwanted manipulation while trying to write a program into my 67 or have put it into a mode that I can't exit any more.
After having taken a look into the manual I don't really understand this mode. I am no very deeply involved into maths I have to say.

The problem:
It look like if I would be stuck in base 9 with no decimals. On the right of the display, I read the tenth, on the left, the units from 0 to 9. After nine, the left part resets to zero and the right part increases.

"clx"


"2"


ENTER


"2" + "8" +


Sure one of you will tell me in one second where I am blocked but I am sorry to admit my gap.
Thanks

edit: change thead subject to better reflect the situation

[Maximilian Hohmann]

Hello!

(07-17-2020 08:58 AM)tribidouille Wrote:  Sure one of you will tell me in one second ...

To me it looks as if the calculator is in "SCI" (=scientific, accessed by pressing "g" followed by "DSP" *) mode with no decimal places displayed "DSP 0". This will display the exponent permanently on the rightmost two digits even if it is zero.

However all that should go away and return to "normal" or default when you switch off your calculator. If it doesn't it is broken.

Regards
Max

(*) Note that the HP-67 is one of very few calculators which has the labels for the shifted functions printed underneath the keys on the keyboard!

[tribidouille]

Thanks, ok, so I should change the post subject.

The DSP key seem to work. When I press, the display is off for a tiny while.
But no, definitely, I can't exit that mode. DSP . 2, DSP 5 ... Nothing changes.
Of course, ON/OFF also does nothing on the situation.

Then the HP-67 is broken?
What sounds strange is that calculations (one digit, lower than 10) work, programming works but unusable when I come back to run mode...

(07-17-2020 10:37 AM)Maximilian Hohmann Wrote:  ...
accessed by pressing "g" followed by "DSP"
...

On the HP-67, I guess you mean just pressing DSP as this function is directly accessible on the key:


(pic from wikipedia)

Or do I missunderstand?

(07-17-2020 10:37 AM)Maximilian Hohmann Wrote:  ...
(*) Note that the HP-67 is one of very few calculators which has the labels for the shifted functions printed underneath the keys on the keyboard!

Then, worse that it is broken.
But most bad, I like it very much.
I just found it in a box with electronics, where it was laying since 15 years. I directly fell in love. Even more than with the 41C. This card thing is so cute, and clever!

I can solder. Also here, it is human sized. If I'd know what component to change (if still on the market), I could replace it. But at the moment, I feel like playing roulette in front of all its components: black, red, which number? :--)

[Moggul]

Switching the calculator off should perform a hard reset on your calculator (no continuous memory). If after switching off the behaviour persists then most probably your PCB is defective.

You can get a replacement PCB from Teenix (http://www.teenix.org) that will most probably make it fully funcional again (plus some extra functionalities). It is a drop-in replacement without need for soldering. I performed the swap a couple months ago and am quite happy with the results.

[Helix]

(07-17-2020 08:06 PM)tribidouille Wrote:  Then the HP-67 is broken?

Stupid question, but are the batteries in good state and fully charged?
Also, dirty contacts under the ON/OFF and PRGM/RUN switches can cause very strange behavior. I had such an experience with a calculator whose PCB was very dirty.
So, try to clean the PCB under the switches, and then put silicon grease, or better dielectric grease:
https://www.hpmuseum.org/forum/thread-13159.html

[Helix]

(07-17-2020 09:43 PM)Moggul Wrote:  You can get a replacement PCB from Teenix (http://www.teenix.org) that will most probably make it fully funcional again (plus some extra functionalities). It is a drop-in replacement without need for soldering. I performed the swap a couple months ago and am quite happy with the results.

I've tried this solution because I wanted internal memory instead of magnetic cards, but unfortunately my replacement board never worked correctly. To make things even worse, I think that mail from France to Australia is inexistent, so I have lost hope in a repair or a replacement.
Now I have a Panamatik new ACT, which works perfectly, and has many useful additional functions (but no card reader ability).

[teenix]

(07-18-2020 12:42 AM)Helix Wrote:  

(07-17-2020 09:43 PM)Moggul Wrote:  You can get a replacement PCB from Teenix (http://www.teenix.org) that will most probably make it fully funcional again (plus some extra functionalities). It is a drop-in replacement without need for soldering. I performed the swap a couple months ago and am quite happy with the results.

I've tried this solution because I wanted internal memory instead of magnetic cards, but unfortunately my replacement board never worked correctly. To make things even worse, I think that mail from France to Australia is inexistent, so I have lost hope in a repair or a replacement.
Now I have a Panamatik new ACT, which works perfectly, and has many useful additional functions (but no card reader ability).

The mail is definitely slow. I am still away on standby work because of lockdowns, but if I don't see a parcel by the time I get home, I'll send you a new one.

cheers

Tony

[teenix]

It might also be worthwhile having a look at the contacts between the CPU board and the keyboard. There might be some corrosion causing poor contact.

Other checks are corrosion on the circuit boards and battery contacts.

As mentioned the power switch could be in need of a clean. The original lubricant if still there would be "gunk" by now.

cheers

Tony

[Helix]

(07-18-2020 01:02 AM)teenix Wrote:  The mail is definitely slow. I am still away on standby work because of lockdowns, but if I don't see a parcel by the time I get home, I'll send you a new one.

Thank you ! Indeed, the current lockdowns cause a lot of problems. After two months, there is no update for my letter on the post office site, so it is probably still stuck in France…

[AndiGer]

Just an idea ... did you try to set different display mode by writing a short program that does just this?

[Maximilian Hohmann]

Hello!

(07-17-2020 08:06 PM)tribidouille Wrote:  

(07-17-2020 10:37 AM)Maximilian Hohmann Wrote:  ...
accessed by pressing "g" followed by "DSP"
...

On the HP-67, I guess you mean just pressing DSP as this function is directly accessible on the key:

Or do I missunderstand?

What I meant is that pressing DSP followed by a number key will set the number of decimal places. Pressing DSP after pressing "g" will put the display in Scientific notation mode.
So both faults (?) seem to be connected to the DSP key.

On one of my HP-67s (I was very lucky to get a near mint one from eBay just last week for a very good price which seems to have been overlooked by our fellow collectors here :-) ) I tried to check if a stuck DSP key might result in the behaviour of your calculator. But no, unfortunately it isn't that easy. It is not just a keyboard fault that can cause this.

(07-17-2020 08:06 PM)tribidouille Wrote:  Then, worse that it is broken.
But most bad, I like it very much.
I just found it in a box with electronics, where it was laying since 15 years. I directly fell in love. Even more than with the 41C. This card thing is so cute, and clever!

Yes, it is a very nice calculator indeed and one of my top-five all time favorites. If nothing else helps it is certainly worth getting a replacement board for it. A good HP-67 can easily be worth 200$/Euros so the money will be well spent!

And regarding AndiGer's suggestion to set the display mode by a small program this is what you could try:

1. Place the "W/PRGM - RUN" switch to "W/PRGM"
2. Enter the following sequence of keystrokes:
f LBL A
f FIX
DSP 2
h RTN
f LBL B
g SCI
DSP 0
h RTN
3. Place the "W/PRGM - RUN" switch to "RUN"

Pressing the "A" key should put your calculator into the normal operating mode displaying "0.00"
Pressing the "B" key should put your calculator into the mode of your machine displaying "0.__________00"

Good luck
Max

[tribidouille]

Dear members,
Thank you to everybody. I am impressed by the number, diversity and quality of the answers!
To make it short, it is dead, teardrops!
As my post is long, so much to answer, thanks again, I'll use Bold to allow reading faster.

@Moggul: thank you for the http://www.teenix.org link. Very very interesting solution to fix pcb problems and make it alive again.
In addition, (I never use bluetooth but cables). bluetootth is so anachronic that it is a must -IMHO.

@Helix: Good question instead: batteries. I did use an external 25 years old german stabilized power source set to 3.6V. I wanted to test the lovely device prior to renew the battery pac. This power source has been used on lots of electronic devices but: I now slap my forehead: for sure, the HP-67 is too sensible for that. Isn't it?
What a donkey!

(07-18-2020 12:31 AM)Helix Wrote:  ...
Also, dirty contacts under the ON/OFF and PRGM/RUN switches can cause very strange behavior. I had such an experience with a calculator whose PCB was very dirty.
So, try to clean the PCB under the switches, and then put silicon grease, or better dielectric grease:
https://www.hpmuseum.org/forum/thread-13159.html

On/off switch: cleaned, no effect. but: if this switch contact quality is important, I'd surely also mention the golden blade making contact between the two (positive) pins of the battery plug (on the calc. side). It seems to me that this blade is connecting these pins when the charger is unplugged and disconnecting by being pushed away when the charger is connected. As power from the battery runs through here, it is also important to have a good contact, I'd say. Or?
The Panamatik new ACT solution is also interesting but solves less potential problems as the pcb is not replaced if I correctly understood. I also like card reader too much, even more than an USB stick!

@teenix: all contacts cleaned. No way.

(07-18-2020 10:25 AM)Maximilian Hohmann Wrote:  ...
What I meant is that pressing DSP followed by a number key will set the number of decimal places. Pressing DSP after pressing "g" will put the display in Scientific notation mode.
So both faults (?) seem to be connected to the DSP key.
...

Sorry, I messed up. But no, the key is ok.

(07-18-2020 10:25 AM)Maximilian Hohmann Wrote:  ...
And regarding AndiGer's suggestion to set the display mode by a small program this is what you could try:

1. Place the "W/PRGM - RUN" switch to "W/PRGM"
2. Enter the following sequence of keystrokes:
f LBL A
f FIX
DSP 2
h RTN
f LBL B
g SCI
DSP 0
h RTN
3. Place the "W/PRGM - RUN" switch to "RUN"

Pressing the "A" key should put your calculator into the normal operating mode displaying "0.00"
Pressing the "B" key should put your calculator into the mode of your machine displaying "0.__________00"

Good luck
Max

Not working (tryed twice to avoid typos)
But Wow! This is magic. I used to practice basic, C++, python, HP-41C that I don't remember the syntax... but this is just beautiful. Thank you even if it failed (because of my 67 failure, no your code).

Now, two side questions. I need a pretext not to leave, so if one has too much time :--):
-I read "Woodstock Series" here and there. What is it exactly?
-How do you solve the HP-&/ sticker problem to access the screws? Do you gently unstick it with a part of cutter blade or do you make a clean hole into it?

[tribidouille]

@teenix: too nice project, I an cracking, I'm yelding to temptation, I shouldn't: please send me one of these boards! Seriously!
But not Helix's one! :--)

[rprosperi]

(07-18-2020 09:36 PM)tribidouille Wrote:  -I read "Woodstock Series" here and there. What is it exactly?

The Woodstock Series includes the HP-21, 22, 25, 25C, 27, and 29C; they share common industrial design and internal electronics technology. More details can be found here. As the article shows, several other models, including the HP-67, share the same electronics design (though with several key changes, such as Card Reader, improved power supply, etc.)

[Moggul]

(07-18-2020 09:36 PM)tribidouille Wrote:  -How do you solve the HP-&/ sticker problem to access the screws? Do you gently unstick it with a part of cutter blade or do you make a clean hole into it?

Both options are good and it depends on your personal preferences. "Serious collectors" prefer the unsticking method so as to keep the unit as original as possible while "users" (like me) prefer the hole method so it is easier to open the calculator again for further repairs.

Anyway you can buy replica stickers on ebay so choose whatever method suits you best

https://www.ebay.es/itm/Hewlett-Packard-...SwsHRc1xJt

[Massimo Gnerucci]

(07-19-2020 10:14 AM)Moggul Wrote:  while "users" (like me) prefer the hole method so it is easier to open the calculator again for further repairs.

You don't have to reseat those two screws, once removed, to perfectly close the unit.
So, no need to make a hole through the label.

[grsbanks]

Agreed. My HP-67 no longer has those screws specifically so that I don't need to damage the label in order to re-open the machine if/when necessary.

[tribidouille]

Ok, I'll live without the middle screws too.
Thanks a lot to everybody for all these answers.
I'll be away until end of august and will continue the repairs then.
Best regards

[mbielman]

Tribidouille,

I had (still have) an old 67 that did (does) the EXACT SAME THING! Turns out there is a bad RAM location (I forget the actual address) that causes this. I believe it's in ROM4 (1818-0232) which is not all that helpful w/o a donor board.

Interestingly, at least in my case, if I leave it ON for a while while in this state (1/2 hour or so) it corrects itself and works OK except that one of the RAM locations remains bad which shows itself as PGM steps which you cannot change.

I had (have) another 67 that was so bad it would not display anything. Replaced the board in that one with the CPU board from Teenix. Works great!

regards,
Mark

[Hiwi]

Hi,
i have another display problem, see picture.
My HP-67 is in very good condition and working well, however there is one part of the segment in the exponent sign permanently turned on.

Is this a problem of the display or driver IC? (Cathode or anode driver)
Has anyone seen this before?

The exponent and the normal sign are working as expected.

Ralf