HP12C  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: HP12C (/thread70213.html) 
HP12C  Mike Willis  03082005 Two questions regarding the HP12C. Re: HP12C  Tom Sherman  03082005 Mike, 1. The serial number should be stamped in the upper right edge of the backside. (A few units are said to have no serial number at all.) 2. Sounds like you will have good use for the 12C, as you will need to recalculate things each time an irregular payment is made. For a given balance and interest rate, the next period requires a certain amount of interest to be paid. If the payment exceeds this interest, the balance is diminished accordingly. If the payment is less than the interest required (not likely, we hope), then the balance must go up by the amount lacking. An amortization schedule does all the calculating for you, so long as the payments are regular in amount and frequency. An irregular payment means that the amount of interest due on the next payment should be recalculated (based on the new balance),and the amortization schedule revised  you can keep the standard payment the same, but revise the time required to reduce the loan to zero. Hope this does not muddy the waters. Others on this forum can explain the matter much more clearly.
Cheers, Tom
Nice Explanation, Tom! (nt)  Larry Corrado  03092005 .
