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isanchez · 10-22-2019, 07:51 AM

Hi,

this is more or less the same issue with the led segments in the display of the classic models.

The new for me, is that the upper horizontal segment of all the consecutive digits from the 6th to the 10h position that do not light up. (I start counting from left, taking into account the first led bulb, dedicated to the minus sign).

So, the failure is in the second group of five led bulbs (the HP35 has three groups of five led bulbs, that compose the display)...in all upper segments of these five digits.

Can you give me a clue of where is the problem: in the group of five led digits it self or in the anode (or cathode...I never remember well), maybe a bad contact?

The calculator is the best HP35 v4 model I have seen. Looks like never used. For me it will be a pain to remove the back label. ;-(

Thanks and kind regards

Ignacio

teenix · 10-22-2019, 09:27 AM

Check pin 7 of the LED display module. It controls the A segment, it might be open circuit.

The PCB track is unlikely to be the problem as it probably also goes to the next LED module which you say works.

If all looks ok, then the LED module has probably gone faulty.

cheers

Tony

isanchez · 10-22-2019, 02:20 PM

Thanks a lot!
I shall check this...If I can get over ruining the back sticker.... ;-(

Harald · (This post was last modified: 10-23-2019 06:48 PM by Harald.)

(10-22-2019 02:20 PM)isanchez Wrote: Thanks a lot!
I shall check this...If I can get over ruining the back sticker.... ;-(

Please don't ruin the sticker. Carefully heat it up with a hair dryer, then peal it off slowly. After you removed it, you can straighten it between two plastic sheets using the curved side of a spoon. The procedure is describe here in the forum in detail.

Cheers,
Harald

isanchez · 10-24-2019, 03:01 PM

Of course, Harald! Thanks...I do it always very carefully, but I am a collector and this means absolutely "maniac" ;-D...it does never keep as it was previously.

(10-23-2019 06:42 PM)Harald Wrote:
(10-22-2019 02:20 PM)isanchez Wrote: Thanks a lot!
I shall check this...If I can get over ruining the back sticker.... ;-(

Please don't ruin the sticker. Carefully heat it up with a hair dryer, then peal it off slowly. After you removed it, you can straighten it between two plastic sheets using the curved side of a spoon. The procedure is describe here in the forum in detail.

Cheers,
Harald