Need help with Project Northstar/Data I/O System-19/ADM Terminals

Ian King IanK at
Fri Dec 17 23:55:18 CST 2010

Many moons ago, I was responsible for the electronics in a recording studio (in the days of analog).  Given that the musicians usually smoked like stacks, I made a habit of taking home the PCBs from the recording equipment, running the dishwasher (with no soap, as Allison notes), drying them by hand and then airflow.  Signal-to-noise ratios  and reliability of control systems increased noticeably.  -- Ian 
From: cctalk-bounces at [cctalk-bounces at] On Behalf Of allison [ajp166 at]
Sent: Friday, December 17, 2010 7:02 PM
To: On-Topic Posts Only
Subject: Re: Need help with Project Northstar/Data I/O System-19/ADM Terminals

On 12/13/2010 09:56 AM, Robert J. Stevens wrote:
> I am trying to restore a N* Horizon,. So far I have got the ZPB-A2 CPU
> card working. I added the Prom Option and am using a 2708 EPROM with
> Monitor Code by Dave Dunfield. A Friend burnt the Prom for me but I
> has a problem and doesn't get the Keyboard Input. I have tried several
> times to Burn a new Prom with my D/I Sys-19 but they don't behave as
> they should. I have a SOL20 System/Bus Probe Card that single steps
> from the get go and I can step through the Code and see how it behaves
> in relation to the .lst listing. I have been using my Canon Book 10
> running "TERM" to talk to the N*. It talks OK to the Sys-19 as well as
> other machines. I lost both of my Televideo 920/25's. I had three ADM
> LSI's in the Shed/Barn but the Field mice made their nests in two. The
> one that was untouched I brought in the Other day and It lights up the
> Mini-Tracker showing that the ADM is setup as DTE. But I get no
> response from the Keyboard. Tried looping back 2-3 but no display.
> Don't see any Raster but the tube POPs up a spot when turned off. I am
> going to try to pull the Mother board out of the Other Micey ADM.
> Maybe I can swap the M/B's and see if that CRT is working. Same for
> the One still in the Barn.

> What would my chances be of soaking it and getting all the CRAP off it
> and having it WORK????? probably ZILCH.
Chances are very good it will work.

The process is to wash it with water and very mild soap (woolite is
good), then rinse, then rinse(not a typo)
then rinse in 91% isopropanol (drug store).  Air dry then oven dry at
180F or less.   In that era PCboards
after wave soldering  were routinely washed in what amounted to a dish

The only item that can be twitchy for water is DIP switches as they are
hard to dry out.  Isopropanol
and a can of compressed air works.  One absorbs the water and the
compressed air to move it out.

I've used that approach on S100 board, terminal main boards, PC
mainboards that were dust encrusted,
whole communications radios (with some parts that cannot be wetted
removed) and after 4 decades
of doing that no damage from cleaning.  My favorite method is the
dishwasher with out the usual caustic
(dishwasher soap is caustic) and nothing but water, boards usually look
as good as new.

> I bought about 5 2708's and If I can find someone who might load the
> New Code for me I could send them a 2708 and E-Mail the .HEX file.

The Parts must be UV erased before programming (usually 20 mins for old
2708s), verify blank
before programming.


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