Hp-41C card reader - dead

[rprosperi]

(05-13-2020 01:54 PM)toml_12953 Wrote:  

(04-30-2020 10:54 PM)rprosperi Wrote:  I definitely recommend Energizer over Duracell batteries.

I've had bad luck with Energizers. They last about 75% as long as the generic brands from Harbor Freight and Aldi's supermarket for my calculators (HP-50, various TIs) Dollar store alkalines last about the same amount of time as Energizers for me.

I have not done too much battery life testing by brands, you could be right. But my priority is to buy a consistently-safe brand, that will not leak and damage my precious toys. I have batteries in honestly far more machines than I use regularly, just to make instant gratification a bit better when I reach for one of those machines. I've had many Duracell failures/leaks over the years, but just the one Energizer (my fault).

I don't know for sure, but I doubt that Harbor Freight or Aldi's maintain the same level of consistent manufacturing as Energizers, likely made by different Chinese manufacturers for each new order or year or batch, etc.

I may pay a bit more for the same number of playtime-hours, but it's worth it to me.

Here's a pretty good video about battery life tests for several popular brands.

https://www.youtube.com/watch?v=V7-ghrTqA44

[Vintage63]

Now the card is not pulled smoothly and I hear the o-rings slipping on the card and it stops inside, so I have to pull it out manually.
Shall I try with another pair of o-rings ?
I tried tuning the axle that holds the wheel too hoping it would lower the wheel but nothing changes.

Thank you so much for your amazing support up to this point guys !!!
Marco

[AndiGer]

Sounds like the coupler / dampener is the candidate now ...
I.e. motor axis to worm gear.
There are several approaches if it is the problem.
Often a tiny drop of cyanacrylate is your friend in this case ...

[Dave Frederickson]

(04-30-2020 10:54 PM)rprosperi Wrote:  I definitely recommend Energizer over Duracell batteries.

HP blacklisted Duracell decades ago.



  Duracell.pdf (Size: 641.35 KB / Downloads: 16)

[Vintage63]

Hi Andy, you mean the bits that are mentioned in this old post ?

https://www.hpmuseum.org/forum/thread-13512.html

Coupling repair ? It looks obscure to me as to what to do.
Ihave to remove the motor from its support first and then check this component if it moves freely or not before applying super glue ?

I really don't like having to reopen this thing for the n-th time :-(

Marco

[AndiGer]

Hi Marco,
Yes the mentioned thread is one of many touching this problem. Often the coupler is named "clutch". HP65/67/97 card readers suffer the same problem.
If you search the museum (best done by google) after "clutch repair" you will find many threads.
Here is a former one where Randy explains the clutch problem resulting in Checksum Error or in Malfunction: https://www.hpmuseum.org/cgi-sys/cgiwrap...ead=131514
Last year Alberto Fenini posted about a repair approach using the inner part of an antenna cable. He put the pics to his iCloud drive. I can't find the thread now. I didn't try this method but thought it is a very good idea.

In my experience the card not running smoothly is the clutch problem. If you try several more cards to run thru the reader often the clutch will slip more and the motor spins at high speed and the card doesn't move at all.

EDIT: To keep the cover off the reader until you are sure it works fine is a good idea :-)

[Vintage63]

I have kept the cover off throught all of these trials
I'm worried about the screws not screwing anymore if I keep removing the motor assembly bits and pieces :-(

Found some other threads on the clutch by following your advice. I checked that the o-rings were installed correctly too. It might be the clutch if the 'holding' mechanism is made of the same material of the infamous 'gummy wheel'.

I have to confess that this 82104A has been left in the basement and in boxes all through my various moves around Europe for the last 20 years and I just now decided to use it again.

The serial number is 2054S47015 - so it was made in 1980
When I luanch CATALOG 2 it says CARD something E1
The 41C is 2052A00467 :-)

Marco

[Sylvain Cote]

I suggest that you look at Geoff Quickfall HHC 2014 video on HP-41 Card reader drive wheel and dampening couple replacement demonstration.

[AndiGer]

Sorry, IIRC Geoff didn't finish the live demo job and broke the aluminium sleeve :-(

[rprosperi]

(05-14-2020 04:52 PM)Vintage63 Wrote:  The serial number is 2054S47015 - so it was made in 1980

Interesting... it was made during the 54th week of 1980, which might mean the 2nd week of 1981...

Such mfg. numbers have been reported several times in the past, no one has any conclusive explanation for what it really means. But one thing seems to be clear, they sure made a lot of card readers that week.

[teenix]

(05-14-2020 04:52 PM)Vintage63 Wrote:  Found some other threads on the clutch by following your advice. I checked that the o-rings were installed correctly too. It might be the clutch if the 'holding' mechanism is made of the same material of the infamous 'gummy wheel'.

Simple coupler repair

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

cheers

Tony

[Vintage63]

this is for the HP 97, does it work on the 82104A ?
Thank you

[Vintage63]

I have removed the clutch assembly.

This is what I have understood. Text in the photo

   


This is what I have understood. Text in the photo
   

Are my assumptions correct ?
Thank you

[teenix]

(05-15-2020 02:30 PM)Vintage63 Wrote:  I have removed the clutch assembly.

This is what I have understood. Text in the photo




This is what I have understood. Text in the photo


Are my assumptions correct ?
Thank you

The worm gear looks identical to 65/67/97 ones.

The coax repair does not need the aluminium sleeve.

cheers

Tony

[Vintage63]

can a satellite dish coax cable work or it has to be bigger, like the white ones used to connect TV aerials ?

I hope I can find one at my local supermarket otherwise I'll have to try B&Q here in England.

I'll update on the reuslts when I have positive news, hopefully :-)

Have a nice and safe week end everyone :-)

Marco

[teenix]

(05-16-2020 09:39 AM)Vintage63 Wrote:  can a satellite dish coax cable work or it has to be bigger, like the white ones used to connect TV aerials ?

Marco

I used RG58 coax available from most electronic hobby outlets. It has the right inner hole size for the motor shaft.

Details here...

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

I'd send you some but I just got asked to fly again and not sure when I'll be back home.

cheers

Tony

[Erik-M]

With one of my cardreaders I had to glue the orings to the axis of the gearwheel because they were slipping resulting in a lot of checksum errors. I used a tiny drop of superglue.
Maybe its not the clutch/dampener.

[David Hayden]

This is the hardest part of the repair. The piece you're looking at is a dampening couple. It's a cylinder with one outer diameter that the metal sleeve slips over. But the inner diameter on one end slips over the motor axle and a different inner diameter on the other side fits over the end of the worm gear.

To create this, I used two different cylindrical materials: one that had the wider diameter to fit over the worm gear and one with the narrow diameter. I pulled the narrow piece into the wider piece. It took a while but I eventually settled on wire insulation for the inner piece and shrink wrap for the outer piece. The trick was hitting the combination with just enough heat to shrink it to the right size.

Other posts have pointed out that shrink wrap can be perilous here. If you shrink it down too much, it gets hard, which defeats the purpose of the dampening couple.

Good luck. Have patience.

[Vintage63]

In my tool box I have found this cable.
Unfortunately I don't think it is good for the 'clutch' as it is quite stiff / rigid.

Anyway I did some practiced stripping the inside insulation and I have a couple of questions:

1) the piece of insulation has to have a perfect center hole, correct ?
2) as the hole I have is too tight it doesn't fit onto the copper gear worm axle. Do I have to enlarge it a little bit before sliding it on ?

I have a black satellite dish cable in the flat which sticks out from under the floor. This has a flexy feel and touch to it.
I'm not using satellite at all so, maybe, I could cut a piece off this and hide the rest and give it a go ?

   

   

   


Thank you

Marco

[teenix]

(05-17-2020 12:39 PM)Vintage63 Wrote:  In my tool box I have found this cable.
Unfortunately I don't think it is good for the 'clutch' as it is quite stiff / rigid.

Anyway I did some practiced stripping the inside insulation and I have a couple of questions:

1) the piece of insulation has to have a perfect center hole, correct ?
2) as the hole I have is too tight it doesn't fit onto the copper gear worm axle. Do I have to enlarge it a little bit before sliding it on ?

I have a black satellite dish cable in the flat which sticks out from under the floor. This has a flexy feel and touch to it.
I'm not using satellite at all so, maybe, I could cut a piece off this and hide the rest and give it a go ?


Thank you

Marco

Yes, centred would be good to minimise vibration and be the correct size to mate with the motor shaft.

The drill size to attach the worm gear is 5/64". It should be drilled into the coupler just enough so that the worm gear fits snugly. It must also be drilled central to avoid vibration.

this link has more detailed info.

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

The coupler must not be any longer than the aluminium sleeve or it may rub against the motor casing and put too much load on the motor.

RG58 coax inner insulator is pliable and a good hole size once the central copper wire is removed which makes it easy to attach and bind to the motor shaft, but it is also stiff when cut to the coupler length.

I think if the white coax sheath is too stiff, it may not easily expand onto the motor shaft meaning excessive force may be required to fit it or it may slip.

cheers

Tony