HP 2113B service manual / schematics

[Bob Shannon]

Your -2 supply sounds just fine.

This supply voltage is used to terminate the I/O backplane, making the
bus signal levels compatible with the original HP 2116, which used CTL
logic.  The 2113's processor uses modern TTL, with special drivers for
backwards compatibility of the I/O bus.

As to the power supply, there are about 20 different revisions, some with
battery backup, some without.

I think the schematics are on Al's web site for the processor.  I'm less
sure about the power supplies.

----- Original Message ----- 
From: "Peter Brown" <peterbrown10 at hotmail.com>
To: <cctalk at classiccmp.org>
Sent: Monday, November 15, 2004 2:17 PM
Subject: HP 2113B service manual / schematics


> Hi All,
>
> I'm in the process of powering up a 2113B.  I took a look at the output 
> voltages from the PSU and they all look fine *except* the -2 volt line 
> that appears to be running at -2.47 volts.
>
> I have the 2109B / 2113B installation and service manual but the service 
> procedure just talks about adjusting the 5 volt line and all the other 
> supply voltages tracking this one.
>
> I can't find a schematic for the power supply in the documentation that I 
> have 02109-90015.
>
> Questions:
>
> 1.  Is my copy of 02109-9005 (Installation and service manual) incomplete 
> i.e. should there be a schematic in it?
> 2. Does anyone have a schematic for the 2019B / 2113B computer power 
> supply. Note that the 'B' is important as the power supply was revised 
> between the 'A' and 'B' models.
> 3.  What is the -2 volt line used for?
> 4.  Does it matter that the -2 volt line is outside specification?
> 5.  Is a full schematic available for the 2113B computer? -  I'm sort of 
> interested in what exactly is going on on the motherboard.
>
> Many thanks
>
> Peter Brown
>
>