HP 260 / HP 250 Preservation Project

04/08/2017

Cleaning a HP260 45261D model

22/10/2013

Système muti-utilisateurs et mutli-tâches introduit par HP en 1978. Ce modèle a un design original car il fait office de bureau avec le clavier intégré, un écran avec des touches de fonction en bas de l'écran directement sous l'affichage du texte précisant la fonction. Système en cours de nettoyage avant restauration dans le but de le remettre en service.

Muti-user and mutli-tasking system introduced in 1978 by HP. This model has an original design because you can use it as a desk with an built-in keyboard, a screen with function keys directly below the the text.

01/10/2013

Removing all the dust from the computer and peripherals

01/10/2013

Detailed view from the HP 240/40 system that I searched in Germany. The system is composed of (1) an HP 260/40 with 1 Mb of DRAM, it's possible to connect up to 4 video terminal and 7 RS232 devices (terminals or printers) and there is also an HP-IB interface for mass storage (2) an HP 7958B hard disk drive with 155 Mb capacity (3) an HP 9144 cartridge tape drive

01/10/2013

On the computer side, we find a BNC and a DIN-6 connector. On the terminal side, the Cinch connector is pluged to the monitor and the DIN-6 connector is pluged to the Audio Interface.

01/10/2013

Here are pictures of an HP 35731B Video terminal with the HP 45262-60010 Audio interface and an HP 46021A Keyboard. The HP 260 use the HP-HIL protocol (HIL stand for Human Interface Loop) to communicate with the keyboard and also produce Beeps. Electrically the HP 260 interface is a variant due to the maximum length of 100 meters. The HP-HIL protocol is described in the HP Journal in june 1987http://www.hparchive.com/Journals/HPJ-1987-06.pdf . In the document,http://bitsavers.informatik.uni-stuttgart.de/pdf/hp/9000_300/98700-90039_98700H_CE_Handbook_Aug85.pdf we find that there is a lenght limit of 2.4 meters between each HP-HIL device. The HP 260 use differential driver and receiver buffers (75179A) to enhance the maxiumum length.

01/10/2013

01/10/2013

This interface is intended to connect the HP-HIL keyboard and convert TTL levels to differential levels. The interface is also responsible to produce Beeps.

01/10/2013

Replacment of the 6V / 2.5AH lead battery by a 6V / 2.3AH NiMh battery. The charging circuit in the HP 260 is not adapted to charge this type of batteries, that's the reason of the diode on the PCB. This battery is intended to keep the time in the RTC circuit.

12/01/2013

Replacment of the 6V / 2.5AH lead battery by a 6V / 2.3AH NiMh battery. The charging circuit in the HP 260 is not adapted to charge this type of batteries, that's the reason of the diode on the PCB. This battery is intended to keep the time in the RTC circuit.

01/01/2013

Removing all the dust from the computer and peripherals