|Re: HP 3421 DC power option|
Message #2 Posted by Reinhard Hawel on 8 Nov 1999, 7:14 p.m.,
in response to message #1 by Joe
The service manual for the 12VDC option (3421-90009) (page 1-2) says:
1.6 The 12V battery option allows the 3421 Data Aquisition and Control Unit, an HP-41C/CV or HP-75C Handheld Computer, an 82161A HP-IL Digital Cassette Drive and an 82162A HP-IL Thermal Printer to be operated from an external 12V sourcem such as a standard 12V automobile battery. ...
1-7 A cable assembly has been supplied with this option that will, when plugged into the rear panel of the 3421A, provide power supply output ports for the computer (HP-41C/CV or HP-75C only), cassette drive (82161A only), and printer (82162A only). This assumes, of course, that the battery option is connected to an external 12V source. These power supply ports are not active when the 3421A is connected to the AC line only.
!!! I'm not sure, that it would be good connecting the battery AND the mains at the same time !!!
The service manual for the 12VDC option (3421-90009)(page 8-1) says:
8-7. This option is designed to operate from an external power source having a having a voltage of between 11Vdc and 15.3Vdc. The external source voltage is used to generate the HP-41C/CV or HP-75 power supply voltage (9.5Vdc-10.5Vdc), plus the printer and cassette drive power system voltages (8.15Vdc-8.7Vdc). ...
I can see, that the controller voltages are generated by a transistor (2N4037) and regulated by an operational amplifier. The other voltages are generated by an 7885C regulator (8.5V)
The 3421A Data Acquisition/Control Unit 3056DL Data Logger Technical Data, November 1985 (5953-6975)
says on page 19:
Option 214 battery connection (Note the option 214!!!)
- blah blah 12 Vdc source blah blah - Extend battery lifetime of the HP3421A and other system devices such as the HP71B, HP2225B, and HP9114
SPECIFICATIONS OF OPTION 214 WILL BE AVAILABLE IN LATE 1985 (I don't have them)
That's what I know. I have the HP-IB interface on mine and so I can't use the battery option and I don't have one. Sorry, no experience.
I'd not see any problem connecting other peripherals, though I would keep the controller connected to the "controller" plug just because of more voltage. Might be, that they didn't want to overheat the power circuitry of the peripherals, but maintain a healthy supply to the controller. I don't have a clue.
BTW: Do you have or do you know anybody who owns a 82479A Data acquisition pac ROM ?