Calculator blog

Musings and comments about our common interest


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Just received more zebra circuits

Until now we have been using a test order of zebra PCB circuits ( Zebra PCB version 3)


We have just received the definitive version (v4) which has a slightly modified dimension to have a better fit (we're talking tenths of mm) and a more precise alignment of tracks.

All orders received this week end are already supplied with the new model

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More pictures of the new zebra prototype


You can see now some more pictures of the new zebra model:


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Repair your calculator during the lock down!


Now we are locked down due to the Coronavirus global pandemics - and it is likely that we'll have to stay for at least a couple of weeks. Now is the time to start things that we didn't have time in the past to do.

DSC_7337One thing is to fix everything that doesn't work at home - and probably this includes your old calculator.

I have started to repair calculators only recently. The repairs performed were increasingly complicated, but at the end I got Ignacio Sanchez's help and we designed a series of parts that help us in these repairs. But the first you need to do is the diagnostic of the damage.

During the next days we will discuss how to repair yours. However, my goal for this instalment is to make you believe that your calculator can be repaired. In my experience , 90% of HP41c calculators can be repaired - and I'd say that 70% are really easy to repair. And this means that YOU can repair it. 

Even very destroyed calculators are repairable. Curiously, the worst calculators to repair do not show any damage. In many cases users put the wrong battery model and burn the calculator with much higher voltage than needed (for example, put four a23 batteries (12v * 4 = 48v) instead of the 6v that are produced by four 1.5v LR1 batteries. Then the screen is burned and then you need to wait for a donor calculator - something that doesn't happen quite often.

But for the rest of the repairs, there is a solution!

We'll look into it in the following blog issues.

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