HP41 display segments fail



A few months ago I purchased a HP41C with problems, to try to repair it.

The contacts of the batteries were completely oxidized. First I washed everything with isopropyl alcohol and repaired contacts with copper adhesive tape.

After installing the battery pack, the calculator switched on OK.

But the display had little contrast and there were several segments that failed.

After runnig the Service Module tests, all the tests went OK. Even the Display Driver test.

I removed and disassembled the display module. Cleaned the zebra connector and the driver PCB with isopropyl alcohol. Pressed a little the assembly clips.

I mounted the display on the calculator, and turned it on. It was alive!! I noted that the display contrast was already OK. Many of the segments that failed before, now are OK. But yet there are a couple of segments unstables and sometimes do not light.

Do you have any idea to help me to repair the display?
What else can I do?



The worst 41 problem to troubleshoot...

Bad/missing/dim segments can be either a bad driver, bad lcd or bad connections. The usual culprit is the LCD itself. The only method to troubleshoot is to exchange both with known good parts, changing each one and retesting. Very tedious.

A caution: There are many different versions of the display and driver, some are incompatible with each other, some require a capacitor change on the logic board. Worst case is that you may need both parts together as a set along with a logic board. Best case is that the replacement parts you find are the same type as what you have.

Be aware that display problems are common on units with battery leakage. Buying another non-working unit is not always the best way to get parts.

Edited: 8 Feb 2008, 9:00 a.m.


Thanks for the response, Randy.

So, it is difficult to resolve this problem. I´ll try again to clean the zebra connector. I think the driver is OK.

Maybe the connector is slightly deformed and there is not good electric connection between the driver and the LCD.

Best regards.


Possibly Related Threads…
Thread Author Replies Views Last Post
  Missing LCD segments (48 SX) Matti Övermark 2 1,350 09-18-2013, 03:50 PM
Last Post: Matti Övermark
  HP-12C: Missing Segments Stefan Ramonat 2 1,421 06-28-2013, 10:59 AM
Last Post: Stefan Ramonat
  Too wide spaces between segments of emulated WP34S? René Franquinet 3 1,501 02-22-2013, 11:14 AM
Last Post: René Franquinet
  HP41 display clean up Wolfgang 4 1,468 02-18-2013, 02:13 AM
Last Post: Bruce Larrabee
  Can the display for a HP32Sii be replaced with the display from another model? Bruce Larrabee 8 2,811 10-10-2012, 10:05 PM
Last Post: Luiz C. Vieira (Brazil)
  HP41 Display Problem Fouad M. Kaadou 3 1,659 06-29-2012, 07:46 AM
Last Post: Fouad M. Kaadou
  LCD repair tip: Missing segments on heat seated ribbon McAllan 7 2,357 03-11-2012, 08:50 PM
Last Post: Joerg Woerner
  missing segments on 20b running 34s db (martinez, ca.) 4 1,627 10-05-2011, 01:27 AM
Last Post: Walter B
  My First HP Calc to Fail Jandro Kirkish 4 1,405 09-07-2011, 06:19 PM
Last Post: Chris Randle (UK)
  32SII-FAIL 8 Jim Yohe 15 3,263 02-16-2011, 03:52 AM
Last Post: Paul Dale

Forum Jump: