Solar calculator, bad cap?

Thread Starter

upand_at_them

Joined May 15, 2010
621
I picked up a second TI-36X Solar calculator, as I really like my first one. This used one is quite sluggish starting up. Would that be the result of the 22uF electrolytic cap going bad? That's the only thing I would be able to replace, anyway.

IMAG1199.jpg
 

Tonyr1084

Joined Sep 24, 2015
5,479
Yes, solar cells DO degrade. Yours is probably very close to 8 years old. If not older.

The PCB has a date code of 0213. That means the 13th week in the year 2002. Given that parts may have sat on the shelf for a few months or longer, 8 years is a fair guess at its age.

The cap? Unlikely at the voltages the PV cell generates. Not beyond the realm of possibility, but I wouldn't expect it to be bad. But hey! It's a cheap replacement. Just keep the polarity correct. I assume you understand the polarity of a capacitor. But in the event someone else may read this post and NOT know, the negative side of the cap is marked by a white side (in your case) but can be any other color. Black, gold, any color. The cap will have a predominant color and the negative lead will be marked with an alternate color of contrast and will not cover the bulk of the cap.
 

Dodgydave

Joined Jun 22, 2012
9,836
Well if there is no battery then it must be the solar cell, just seems strange to put a diode in series with the cell when there's no battery..
 

Thread Starter

upand_at_them

Joined May 15, 2010
621
Yeah, the diode is odd. Second calculator is a different PCB design, but has SMD diode and SMD caps. Unfortunately, I can't see the other side of the PCB and removing it requires undoing all of those melted plastic posts. Not worth it; I'll live with it.
 
Top