HP-19C Help needed

[Renato]

Just got this 19C. Non-functional, in rough shape. No battery pack, no battery door.

Would someone tell me:

1- How to open the case - I removed the 5 screws (2 under feet, 2 in battery compartment, 1 in PS socket), but there seems to be a latch somewhere

2- I know it uses 82059 AC adapter, but I only have 82059D - is it ok for the 19C to use a 82059D ?

3- Does it suffer from the common woodstock fragility on the power supply ? In other words, can it be operated with AC power *without* a battery pack ?

thanks,

Renato

[David Smith]

You have the screws out. The bottom of the case is a lot like a woodstock. Also the case halves are somewhat held together by fork pins between the keyboard and the printer board.

Any 82059 charger should work. You do need a battery pack in the machine for it to work (but I don't think it is as delicate as the woodstocks damage wise).

[Renato]

David,

Thank you. I have the case open - a severe case of battery leakage. Looks like it will require some debugging - lucky me - I´ll enjoy the fun.

What about pinout of the interboard connectors ? - I´ll look for normal DC voltages, before trying to go further. There is some corrosion on the terminal of the diodes on the lower right side of the power supply circuit - four diodes - should be the rectfying bridge. The 1826-0287 IC also has corrosion near it.

Caig Progold cleaned a portion of corrosion. I will work on it .

Thanks again,

Renato

[David Smith]

Corrosion seems to be a rather common problem in these machines. I have seen three or four that were rather badly infested with the green fuzzies. I usually use 91% isopropyl alcohol to start with then go with the more exotic contact cleaners.

A lot of the printer circuitry is very similar to the HP97 and the HP97 service manual on the HPMUSEUM CDROMs can be a help.

[Renato]

David,

Thank you, again.

I managed to get it to turn on. As the logic-board-to-keyboard connector is corroded, i traced the on-off traces to the logic board side connector and shorted 1-2 to 4-5 . Display turned on with "0.00 80", printer purred and display showed "error".

I´m much pleased that it worked - must have been dead for decades. Now I´ll try to fix the bad connector.

Renato

[Michael Meyer]

Let us know if you get it 100%. For "grins", let me know if the little decimal points in the display are little "hp" symbols. About half I've come across are!

The 19C is still my favorite machine to look at, marvel and admire. I think it's a really special calc.

Others have more power, smaller size, etc. And it's a 71B that I still use to play games and as an alarm clock, and a 67 to do my day-to-day calculating.

Can't explain it....

I guess that other machines had card readers (TI), and there were several amazing models. None that I can recall that were classic programmables with a printer. Too bad there wasn't a card reader stuffed in there somehow.... A pocketable 67/97....

It's just a really cool classic calc. (OK, technically a Woodstock, not a classic.)

I can't explain it, but I suspect you'll understand when you have it all working....

Michael

[Renato]

Michael,

Yes, the decimal dots are HP logos. This was the first thing I checked when I got it to turn on. C O O L - I could see the logo without any magnification.

Another yes - for the fascination . For me the "purr" sound of a 97 card reader, printer or the 19c printer is fascinating.

Right now I´m just spending time away from the calculator, just wondering if I will try to fix the keyboard connector, or if I will build a cable to operate the machine with the case open. Former is most likely - if there are other things to fix, it might be useful.

Renato

[David Smith]

I'm sure an old Woodstock or HP97 would be able to supply some pins... or are those the really long ones that went bad?

[Renato]

David,

The gold pins are ok. Corroded connector is the one at the keyboard. I believe it is called a "berg stick" - a row of square holes, in a black plastic housing. Too bad my digital camera went bad (canon S-20 - worst purchase decision i´ve made in the last two years).

Thanks,

Renato

[David Smith]

The HP97 LED module connects to the display driver board with that type of cable and connector. Later machines were soldered on both ends.

[Renato]

As far as I recall, one 97 and three 91 i´ve opened (all made in Brazil) had display soldered to the logic board.

Renato

[David Smith]

Many of them have one end of the display cable soldered down and the other end in a socket.