HP 28c

[Tadeyev]

Hello all,
I recall hearing something a while back about the hinged portion on these models, connecting both halves, being finicky or giving out in older models after long use.
Can anyone enlighten me about that? Also: any impresssions about use, quality?
Thanks,
Tadeyev

[John Limpert]

I haven't seen any problems with the hinges on the calculators in my collection. The main problem is the battery door, which is easy to damage when changing the batteries. I've seen a few calculators with flakey displays. The keyboards seem to be pretty durable.

[James M. Prange (Michigan)]

Agreed; the hinge seems as if it ought to be a likely failure with the clamshells, but I don't recall ever reading of it actually failing.

The battery cover is indeed difficult to to insert, particularly when in a rush to get it in place before memory is lost. Damage to the cover or the case in that area seems to be a common problem.

Regards,
James

[Paul Marin]

The only thing that I've known about that was bad about these units was that when I bought my first units in the late 80's, it kept losing memory if it was shaken a little, say when in a brief case. It was a few months old at the time and after getting frustrated I took it to a HP retailer who, after checking the serial number, replaced it with a new model. He told methat a bad batch were made with faulty battery contacts.
Apart from that, the unitis in pristine condition and I have no trouble with either battery cover or hinge. Nice unit. Won't part with this one foe anything

Paul

[Juan J]

Hello,

Other than the battery door, there are no major problems with the 28C/28S. One of my 28S accidentally hit the ground a couple times but nothing happened.

I had to put my 28Ss under storage for three years, with batteries. All of them had the clock program; when I took them out from storage it was still running and kept time more accurately than a wrist watch.

My two cents.

[Thomas Radtke]

Randy reported broken plastic rivets to cause keyboard failures, not the hinge IIRC. Aside from this potential problem and the battery door, the clamshell models seem to be quite reliable. I have and enjoy an 18C since years and lately got a 19B.

[Tadeyev]

Thansk everyone for the remarks and comments, it was valuable info for this HP collector!

[martin]

hello Juan J,
my son throw away the batteries in my HP28S,thankfull if you can help me what type of battery I need to replace the batteries..Thank you in advance..do have a nice day!!

[Juan J]

Hello Martin,

The 28 uses three size N batteries. These are 1.5 Volts each. If I remember correctly, they are avaible from Eveready as model E90 and from Kodak as model KN. I prefer the latter, because it lasts longer and does not leak.

Be careful, as there are a few models with the same size (for garage door remote controls and similar devices) that are 3 Volts and even 6 Volts each. Check the voltage.

Hope this helps.