HP48SX annunciator line problem

[isanchez]

Dear friends,

I have a working HP48SX, very nice. The external state is mint.

The only issue detected is that the annunciator line (the upper display area, not the dot matrix, but the six predefined symbols: Arrow-left, arrow-right, hourglass, alarm-clock, etc.) does not work. I can see all of them very dim, even if the calculator is off, but no response when activated...I enclose a photo with the calculator turned off.
Maybe you have experience in what could be the problem.
Could be a defective display?or the zebra connector? All keys do work perfect.

If you find it is the display: are the displays from the 48's family compatible? i.e. can I use one from a 48G+ as spare part for the 48SX?

Thanks and kind regards

Ignacio

[BartDB]

Hi,

Early 48S/SX models did have problems with the displays resulting in missing sections of the display.

(06-05-2017 02:10 PM)isanchez Wrote:  If you find it is the display: are the all the 48's family compatible? i.e. can I use one from a 48G+ as spare part for the 48SX?

Yes, I have successfully transplanted a display from a dead 48GX (motherboard failed) to a 48SX.

Regards
.

[isanchez]

Thanks BartBD!
My 48SX SN is 3037A00170, and taking into account that the earliest SN starts with 3003, probably it is defective.
I shall try to find a working one.
Thanks again for your help.

Ignacio

[Paul Berger (Canada)]

(06-05-2017 02:53 PM)isanchez Wrote:  Thanks BartBD!
My 48SX SN is 3037A00170, and taking into account that the earliest SN starts with 3003, probably it is defective.
I shall try to find a working one.
Thanks again for your help.

Ignacio

I have installed the display from a 48G into a 48S and it works fine, they are even a little better display, I have even installed the display from a 39G into a 48G, so it would likely work in a 48S as well and they are the much better grey display, possible donners are 39G, 40G, and 49G for that display.

Paul.

[isanchez]

Thanks Paul! I have found another SX as donor. Now the issue is to open it! Never done before. I have seen some tutorials.

Thanks and regards.

Ignacio

[Dave Britten]

I have a 48G with a similar problem (some of the annunciators are stuck on, some won't turn on at all). But proving that even a malfunctioning calculator can still be useful, it's been my trusty bedside alarm clock for many years now.

[rprosperi]

Suggest you take an LCD from an HP-39G. It is the same (or better) high-contrast black LCD found in later 48GX/G+ machines.

A 48SX with Black LCD is one of the best looking machines ever IMHO.

39G machines can be found on eBay, etc. for under $20, and are (supposedly) easier to take apart.

I'd hate to see another 48 machine sacrificed needlessly, but I've no such reservations for the Algebraic 39G.

[lemontea]

See my recent thread.

I've opened 48s and 39s.

[isanchez]

Thanks for your comments. I have found a (supposedly) non working hp48SX in the box for 15USD. If this works I shall try a 39G.
Lemontea: I have read your thread, it is printed on my desk.

Regards

Ignacio

[lemontea]

Good luck!

I have found aligning the LCD with the PCB is the hardest part. If you can improve on the process, please let us know!