HP-65 1333A20064 serviced by someone ?

[albertofenini]

Hi Everyone,

we are restoring an HP-65 purchased this summer and received in September, the CPU board has a sticker with what looks to be
like a "service date", and some sort of "codes", does everyone know what these mean ?

Our best guess is that has been serviced sometime in the 1983, considering
the serial number, the card reader motor looks like it has been replaced with a newer one.

Usually old units have a card reader motor with the external cover in bare shiny metal
and not painted in green like this one, also the Card Reader amplifier looks to be the new version

Moreover, we have found the the inner side of the battery contacts have been taped
and also an area of the keyboard board, kind of preventing some short circuits

Last, but not least, looks like some small labels have been added in order to achieve the
right pressure between all the various components when the unit gets re-assembled

Any idea ? We will keep posting as our work proceed

Pictures can be found here : HP-65 1333A20064

Take care everyone !!

[teenix]

I'm repairing one for someone and has the same motor casing color. Same Maxon company, probably just a different batch.

The tape would show indents if something like a screw head was protruding onto the circuit board from the black plastic moulding. Adding the tape would also increase the distance between the card contacts and the circuit board. I don't know if that causes timing problems or not, or was a reason for adding it.

The sense chip is from later 67 97 etc. Obviously it still works in the 65 so that might be some good news for someone looking for a replacement.

cheers

Tony

[albertofenini]

We are proceeding with the restoration,
next step will be the card reader and the keyboard
Provisionally we have repaired the keyboard with a slim strip of tape
but at least two lines of keys definitely need to be replaced

Pictures updated here : HP-65 1333A20064 updated

We hope the pictures can be of help for anyone who wants to bring these pieces back to the original glory

Take care !

[albertofenini]

Card Reader done !
The gummy wheel has been replaced with a couple of o'rings and those
have been glued together since when they are not they tent to separate.

The coupler has also been rebuild and the unit reads and writes nicely.

We are not fully satisfied however because since when the coupler has been rebuilt
the sound of the motor has changed

If you listen to the audio of the two clips uploaded in the album
you'll notice that is not continuous but rather sound like a wave
high and low high and low and we suspect that it could be because of two
reasons : the coupler is not perfectly centered or the o'ring are not perfectly
rounded, but it sounds like is not on the right axe ... what do you think ?

Any idea or suggestion is very welcome !
Thanks in advance !!

Pictures and video here : HP-65 1333A20064 updated

[teenix]

It may be oversized and/or eccentric o-rings causing them to put excess pressure on the idler roller and card on each rotation of the drive wheel. Awful stuff as it loads up the motor which will draw excessive current from the sense chip. Both are well on their way to be eligible for pensions so not worth stressing them. If the coupler was out of center, then you would feel some nasty vibration and will eventually damage the motor bearings which are probably suffering arthritis by now, so also to be avoided.

I have repaired quite a few gummy wheels now using o-rings and while they work, most needed attention before fitting and using them. This was a size reduction to make them work freely in the mechanism, otherwise I get symptoms similar to yours. Maybe the original drive wheel material was exactly 1/4 inch, maybe not, I don't know. Either way, because it puts outward pressure on the o-rings when they are fitted to the drive wheel, they expand beyond their original size and I think this is the problem.

When you fit the drive wheel on the axle (without the motor in place) you need to check that it turns freely on any axle adjustment setting. One the widest axle setting, the card should be able to be pushed into the slot quite easily while still turning the drive wheel. This should get progressively harder as the adjustment is made. If you fail to realize this, then excess pressure will be placed on the card during transport through the reader. If there is too much pressure, then you might also risk breaking the tiny axles on the idler roller and that will hurt.

The width of both o-rings can also exceed the drive wheel axle width and cause the outer o-ring side to drag on the side of the wheel well opening.

The other thing worth noting is that there should be a tiny sideways movement on the worm gear shaft when the motor is screwed up tight. If this play is not there then excessive side pressure will be placed on shaft and perhaps the motor bearings.

I have this info available in the Classic Notes PDF.

It's interesting that the o-ring closest to the metal wheel shoulder barely touches, or doesn't even touch the card. It really just serves as a spacer to keep outer one parallel.

cheers

Tony

[albertofenini]

Hi Tony, Hello Everyone

you may be right,
that's also why I prefer to use silicon tubing or o-ring with a square section,
also glueing those to the wheel may have changed the geometry and makes
difficult to remove them and properly clean the wheel

I'll try a different option and let you know

As for the notes, I had not seen them in a while and they have a lot of
additional information in this version, very detailed and well described, thank you
so much for putting together all that information

take care and thanks for all you help !

[EDIT] you positive the o-ring should be ID 1/8" and OD 1/4" ?

[teenix]

(11-10-2021 07:20 AM)albertofenini Wrote:  [EDIT] you positive the o-ring should be ID 1/8" and OD 1/4" ?

As far as I know, that is the type of o-ring used as replacements.

cheers

Tony

[AndiGer]

Quote:[EDIT] you positive the o-ring should be ID 1/8" and OD 1/4" ?

I use 2.90 x 1.78 (in mm) o-rings. I.e. OD 6.46 mm. 1/4'' is 6.35 mm. Very similar.

[albertofenini]

Thank you AndiGer
can ask you where do you buy them ?
Thanks again !!!

[GreyUser]

You desperately need a proper anti-static work surface. A fabric cutting mat and poly foam are not acceptable for handling CMOS devices, the surface charge potential of those materials is frighteningly high.

Round o-rings of the correct size are okay for DIY repairs, square o-rings are by far the best solution and are significantly more concentric and consistent than any model fuel line silicone tubing.

The correct way to determine if your replacement wheel is the correct size and that the eccentric is set correctly is to measure motor current. Apply 3Vdc supply, insert a blank card and when it has 15mm or so remaining, do not release it, hold the end of the card so it stalls under the drive wheel and observe the motor current. Set the eccentric for no more than ~180 milliamps with the card stalled under the wheel and the current should be stable. If the current is >200ma, the wheel is too large in diameter, if the current is unstable, the wheel is out of round or the drive screw is loose on the motor.

This adjustment procedure is detailed in the 82104 card reader service manual. All HP card readers are the same design so this applies to all classic, topcats, etc.

The white label with a date and two letter codes is a repair by the HP calculator service department. The codes are what was done, no list of explanations are known to exist. The green/red motor appeared only in the early 65’s. The bare aluminum version later appeared in the 67 and Topcats and then of course the 82104.

[teenix]

The original HP test for motor current is the best to use if you have the equipment, however, a lot of original and still working couplers will be aged by now and there is a risk of the extra strain caused by this test might tip it over the edge and break it.

Just a thought.

cheers

Tony

[albertofenini]

(11-14-2021 05:44 AM)GreyUser Wrote:  You desperately need a proper anti-static work surface. A fabric cutting mat and poly foam are not acceptable for handling CMOS devices, the surface charge potential of those materials is frighteningly high.

I know, do have any model to suggest me ?

Round o-rings of the correct size are okay for DIY repairs, square o-rings are by far the best solution and are significantly more concentric and consistent than any model fuel line silicone tubing.

This is very true, but these are not easy to find here in Italy, I had once purchased a batch from
an Ebay seller but having those sent from the Us is not fast and/or convenient,
any idea where I can get them in Europe ?

The correct way to determine if your replacement wheel is the correct size and that the eccentric is set correctly is to measure motor current. Apply 3Vdc supply, insert a blank card and when it has 15mm or so remaining, do not release it, hold the end of the card so it stalls under the drive wheel and observe the motor current. Set the eccentric for no more than ~180 milliamps with the card stalled under the wheel and the current should be stable. If the current is >200ma, the wheel is too large in diameter, if the current is unstable, the wheel is out of round or the drive screw is loose on the motor.

I knew that but I had never given a try, I'll check it out

This adjustment procedure is detailed in the 82104 card reader service manual. All HP card readers are the same design so this applies to all classic, topcats, etc.

The white label with a date and two letter codes is a repair by the HP calculator service department. The codes are what was done, no list of explanations are known to exist. The green/red motor appeared only in the early 65’s. The bare aluminum version later appeared in the 67 and Topcats and then of course the 82104.

[albertofenini]

(11-14-2021 05:56 AM)teenix Wrote:  The original HP test for motor current is the best to use if you have the equipment, however, a lot of original and still working couplers will be aged by now and there is a risk of the extra strain caused by this test might tip it over the edge and break it.

Just a thought.

cheers

Tony

Tony I have understood well that you have had the Card Reader PCB re-done ?
Take care !

[teenix]

(11-14-2021 10:09 PM)albertofenini Wrote:  Tony I have understood well that you have had the Card Reader PCB re-done ?
Take care !

Yes, I had some made up. There is a picture on the web page - http://www.teenix.org.

Unfortunately, I should have checked first as the postal service rules changed and is so costly now, that it is hardly worth posting one. It is ridiculous in that if I post the exact same size and weight for a package which has paper instead of the small board, the cost is about 1/7th

I am now including one for free with the CPU board replacements for 65 and 67.

cheers

Tony

[GreyUser]

(11-14-2021 05:56 AM)teenix Wrote:  The original HP test for motor current is the best to use if you have the equipment, however, a lot of original and still working couplers will be aged by now and there is a risk of the extra strain caused by this test might tip it over the edge and break it.

Just a thought.

cheers

Tony

The only thing that breaks is a glue joint, easily repaired with a dot of cyanoacrylate glue. Better to test it properly, have it fail and fix it now rather than ignore it and have it break tomorrow, which it will certainly do.

To the OP: the correct o-ring size is 006. I do not know if this size is readily available in Italy. I do know metric sized parts will not work.

[albertofenini]

(11-15-2021 01:34 AM)teenix Wrote:  

(11-14-2021 10:09 PM)albertofenini Wrote:  Tony I have understood well that you have had the Card Reader PCB re-done ?
Take care !

Yes, I had some made up. There is a picture on the web page - http://www.teenix.org.

Unfortunately, I should have checked first as the postal service rules changed and is so costly now, that it is hardly worth posting one. It is ridiculous in that if I post the exact same size and weight for a package which has paper instead of the small board, the cost is about 1/7th

I am now including one for free with the CPU board replacements for 65 and 67.

cheers

Tony

It looks identical to the original one !! very nice !!! is this just for the HP-65 or can it be used with the HP-67 as well ? I mean, for the HP67 where do you solder the trimmer ?
What's the price for it ?

Take care !!!!

[Ren]

Hey Tony,
I was looking at the PC emulator on your webpage.
Is it still available?
And where do I attach the wrist band if I want it to emulate the HP-01?
B^)

[teenix]

(11-15-2021 01:43 PM)albertofenini Wrote:  It looks identical to the original one !! very nice !!! is this just for the HP-65 or can it be used with the HP-67 as well ? I mean, for the HP67 where do you solder the trimmer ?
What's the price for it ?

Take care !!!!

Works on both 65 and 67. At design time, I did not think of a trimmer because I have never seen it for real, but one can be fitted instead of the resistor if required. It would have to be held in place with a little dab of (non corrosive) silicone.

As mentioned, the international postage for these is ridiculous, so if anyone wants to pay for this, then they are free.

Some cards for birthdays etc have novelties stuck inside them and can be mailed, so I wondered if I stuck one in a HP get well card, maybe it would get through on the cheaper postal rate.

cheers

Tony

[albertofenini]

Tony what would it be the cost of the shipping with tracking number ?
I may put together an HP65 and one HP67 replacement board
and make it worth the cost
Take care !!

[teenix]

Hi Alberto,

It is about $Aus25.00 to ship an airmail package up to 300 grams with tracking. It may be a dollar or 2 either way depending on country. This is the cheapest I can find. Before they changed the rules, it was about $Aus5.00 to ship a CPU board because it fits inside a standard letter size. Now it is classed as goods regardless and cannot be sent that way. If you try, it will be sent back :-(

cheers

Tony