LA210 Schematics

[Allison]

>
>Subject: Re: LA210 Schematics
>   From: ard at p850ug1.demon.co.uk (Tony Duell)
>   Date: Sat, 12 Nov 2005 01:54:04 +0000 (GMT)
>     To: cctalk at classiccmp.org
>
>> >Easiest starting point is to check operating voltages.  If during 
>> >printing they drop or go flakey it's the PS.  The fact that it 
>> >prints at all says most of the logic is solid and working.
>> >
>> >Allison
>> >
>> >
>> >  
>> >
>> One of the reasons I want some kind of schematic.
>> 
>> So I can know what voltage levels should be where, and if I find
>
>There pretty much has to be a +5V line for the TTL, microprocessor, etc. 
>You can find that from data sheets on some of the ICs. I'd start by 
>checking the voltage between that and logic ground (found on the gnd pin 
>of similar ICs). 
>
>-tony

Easier than that Tony.  Pick a voltage on any line and when it start 
printing see if it changes when the printer fails.  No need to know
what the correct voltage is when it prints because it is likely correct
at that time.  However if the printing stops and the voltage does too
then there is a clue.

FYI: LA210 has a main logic with everything and a power supply unit
of the switching variety.  I do believe there is a power Ok signal
from that supply.  I believe it's derived on the logic board.

How if I knew which DEC prints box of the four it's in I could go 
further.

Allison