HP-65 - 1333A19931 full restoration - many pics

[albertofenini]

Hi everyone,
whether not so good, sunday ... we have spent some time at the bench
While we are waiting for a glue and some micro screw to improve our method of sealing the
Woodstock keyboards, today we worked on an HP-65
These have been on TAS for a while, where two units and the original carton, which will restore
as well.
So someone of you may remember these.
We started with the one that had already lifted the upper corners of the back label, and we did
a full restoration.
We think that two things may be of interest for someone :
1. we rebuild the clutch using a different method, we didn't invent it, so we don't want to take credit,
it was described on the forum long ago, and we will call it "external method" , we think is
faster and easier that the traditional method, eventually one can also put back in place
the aluminium sleeve but it is not necessary,
it works and we have read and written successfully a couple of card, it is done using antenna
internal cable, but you will see it in the pictures
2. we used a new type of pencil to redo the upper chrome finishing, they are available
in different size, we used the 1 mm and the result is very shiny, almost like the original.

Please, if putting pictures of commercial products is not convenient tell us and we will remove them

Two more notes :

1. we started to use icloud to share pics, it doesn't consume our quota and we can put hi res
pictures, we will add comments too. However, we don't know how icloud order the pics, so
if anyone knows it, please tell us, so that the pics will show up in the right sequence

2. the most experienced will notice that we re-soldered the power cables of the card reader
in the wrong order, we discovered that once everything was re-assembled, as what happens
is that the card reader runs as soon a battery pack is inserted and turns off when the calculator
is turned on, regardless of any card inserted.
So we reopened, soldered correctly and tested.

We read the diagnostic card, which executed ok, and wrote a blank card with that content,
re-read and retested.
Then we read the card from the standard pac with computation of the ares, tried the area
of a circle, and over written the same blank card with these contests, re read the blank
and verified that it was the same program.

We also did a second external worm gear rebuild, on a spare motor just to better document
the process.

Hope everyone enjoy, take care !!

Pictures here : HP-65 1333A19931 Restoration album

[BobVA]

Very nice! It came out wonderfully!

[rprosperi]

Great job and also great photos showing the process. The final result is beautiful!

Thanks to both you and your son for sharing these with all of us.

[jackrubin]

Thanks - info on chrome pen was just what I needed to clean up my HP-35.

[Archilog]

Impressive result! Bravo!

[Geoff Quickfall]

Excellent result.

Great idea with the “clutch”.

The only point to make for accuracies sake and NOT a criticism:

It is not a clutch, it is a dampening couple used to prevent the vibration inherent in the motor from transmitting to the worm gear and interfering with card read/write.

The reason it became a “clutch” in the vernacular is that it slipped when it aged and restorers mistaken inferred that it was a protection for the motor if the card jammed. The “clutch” would then slip. In fact the motor should stop if the card jams so the trade off in the material selected is rubber enough to prevent vibration and a solid enough grip to prevent slipping.

Well done!

[albertofenini]

Thanks Geoff !!
It was not our idea, we don't want to take credit for this,
we read it somewhere though I can't remember if in the Forum or elsewhere and we gave it a try !
It works well, glad you like it !
Take care !

[teenix]

(10-07-2019 11:04 PM)albertofenini Wrote:  Thanks Geoff !!
It was not our idea, we don't want to take credit for this,
we read it somewhere though I can't remember if in the Forum or elsewhere and we gave it a try !
It works well, glad you like it !
Take care !

Twas me :-)

https://www.hpmuseum.org/forum/thread-12...#pid110378

cheers

Tony

[albertofenini]

That's it !
Here it was, only we used a 50 Ohm cable, but it works quite well !
Thanks Tony it was an excellent suggestion to try out !