HP-82183A... Problem with ASTEC 0950-0408 :(

[Paul Berger (Canada)]

(06-26-2017 09:25 PM)Titi Wrote:  

(06-26-2017 06:02 PM)Dave Frederickson Wrote:  Per the Improper Turn-On Troubleshooting Procedure, Table 4-3, be sure that the battery is good before starting.

Ok. My battery 82033A give 5V. I test with another charger, Eurocharger 82066B.
This HP-82183A was with a 82059D so.

Now, in the motherboard, I get 18v & 5v ! But, LED Power is off ?

There is +5V generated in two places on the board, one is the print head voltage is fed into 78L05 regulator, the other is a switching regulator that generates the +5V logic voltage, the 9100-0425 pulse transformer is part of that regulator. The output from the logic 5V supply and the output from the 78L05 are compared and the output from that generates an active low power good signal which enables the buffers in the 74LS365 chip and two of the gates on that chip have their inputs tied low and the outputs tied together which turns on the power LED and also enables a few other things. See Tony Duell's hand drawn schematic at http://www.hpmuseum.net/document.php?hwfile=3014

BTW I have an old style logic, the 0950-0408 module is not encapsulated, that I believe does work, I connected power and the power light does come on and I verified that the print head voltage and +5V logic where both present. I believe it was a working printer that I scavenged mechanical parts from to fix a 82162A and a printer in a 97. You may have it for the cost of shipping, send me an email if you are interested.

Paul.