I just bought some 18c's exclusively for the battery door for my 28s's broken one.

[Sukiari]

Is this evil? I mean nobody really likes the 18c except as a parts spare right?

The 28 series is interesting to an RPN/ RPL person while sadly the 18c really isn't, despite its incredible capabilities.

[Valentin Albillo]

.

(11-27-2020 12:49 AM)Sukiari Wrote:  Is this evil? I mean nobody really likes the 18c except as a parts spare right?

The 28 series is interesting to an RPN/ RPL person while sadly the 18c really isn't, despite its incredible capabilities.

Do whatever suits you, there's no "evil" whatsoever involved, but perhaps you might consider a less wasteful approach by using instead an inexpensive 3D-printed battery door, either printing it yourself if you have the capability or else buying one for peanuts from someone else.

That way you won't sacrifice a whole calculator for just the "spare" battery door. Also, you might use the 18C's original door in your 28 and get the 3D-printed battery door for the sacrificial 18C. Just an idea.

V.

[RMollov]

(11-27-2020 12:49 AM)Sukiari Wrote:  Is this evil? I mean nobody really likes the 18c except as a parts spare right?

The 28 series is interesting to an RPN/ RPL person while sadly the 18c really isn't, despite its incredible capabilities.

I guess You've done the right thing, AFAIC that's what 18C is good for. Bad news is *new* door might not be any better than the one it replaced...
Good luck anyway

[Harald]

(11-27-2020 02:04 AM)Valentin Albillo Wrote:  ...but perhaps you might consider a less wasteful approach by using instead an inexpensive 3D-printed battery door, either printing it yourself if you have the capability or else buying one for peanuts from someone else.

Has anyone made a 3D model of the clamshell battery door?

[Didier Lachieze]

(11-27-2020 03:29 PM)Harald Wrote:  Has anyone made a 3D model of the clamshell battery door?

At least one person has: HP-28S Battery Compartment Door.

[BruceH]

A new door is all very well but a decent proportion of the broken 28s that I've seen are broken in the body so the door has nothing to latch onto. For these there is no easy fix other than Katie Wasserman's half-length battery fix that takes the pressure off the door entirely. This also avoids the need for a 'donor' machine.

[edryer]

My advice borne of long experience with various 28S "fixes".

Never use the recommended batteries, heavy stress on the door and the device however you try to fix the problem.

Get some dowel, and tin foil, cut one to a size slightly shorter than two watch cells, and the other slightly longer, cover with the foil (you get the picture) use the two watch cells at the top of one of the dowel pieces... this works PERFECTLY with no door stress, I mean ZERO.

Actually I didn't even use dowel as I "moulded" the spacing with just tin foil in the shape of batteries.

Also the watch cells seem to last ages, as long as the usual batteries, don't ask me why.

Not my idea... saw it on the net, works fantastically.

PS. I use this on my 28S and it eliminates all issues, but you always have to be careful when removing/placing the battery door anyway with the 28S (brittle due to age), even under normal circumstances!

The other common 28S issue with the heat stakes... I think Geoff Quickfall investigated and fixed this - not at all easy for mere mortals like me ))
Ok that is here: https://www.hpmuseum.org/cgi-sys/cgiwrap...ead=185173

How I love my 28S, the best HP ever made... pity about the issues but with care you can still use these devices day to day.

[jonese]

Nahh, all good. Don't feel bad it, just don't toss it out!

I replaced a bleeding LCD module on an otherwise pristine HP-16C with an inexpensive sacrificial eBay HP-12C. I have no bad feelings about rendering a HP-12C non-functional in the process. I've kept the remaining parts of the HP-12C "just in case".

As for the HP-28C, I keep mine without batteries now, due to the battery door (and surrounding plastic) weakness. I have numerous other HP's in the collection this is one sits idle on display.

[BillBee]

Brilliant! Thanks for putting this on my radar. The 28s was always one of the calcs that others had in college. My trusty 15c was more than capable but the 28s was next level. I finally picked up one this year and yep the battery door is under great stress. Couple that with aging plastic and "pop goes the door". I will definitely be investigating the dowel/foil replacement.

One thing I did observe by having tape over the door (as reinforcement) was that the tape reduced the torqueing that unit faces when being opened. That torque looks to be a cause of the heat stake ripping. I have been meaning to sand the catch a bit to reduce the force required.

-Bill

(11-27-2020 10:43 PM)edryer Wrote:  My advice borne of long experience with various 28S "fixes".

Never use the recommended batteries, heavy stress on the door and the device however you try to fix the problem.

Get some dowel, and tin foil, cut one to a size slightly shorter than two watch cells, and the other slightly longer, cover with the foil (you get the picture) use the two watch cells at the top of one of the dowel pieces... this works PERFECTLY with no door stress, I mean ZERO.

Actually I didn't even use dowel as I "moulded" the spacing with just tin foil in the shape of batteries.

Also the watch cells seem to last ages, as long as the usual batteries, don't ask me why.

Not my idea... saw it on the net, works fantastically.

PS. I use this on my 28S and it eliminates all issues, but you always have to be careful when removing/placing the battery door anyway with the 28S (brittle due to age), even under normal circumstances!

The other common 28S issue with the heat stakes... I think Geoff Quickfall investigated and fixed this - not at all easy for mere mortals like me ))
Ok that is here: https://www.hpmuseum.org/cgi-sys/cgiwrap...ead=185173

How I love my 28S, the best HP ever made... pity about the issues but with care you can still use these devices day to day.