[GreenKeys] ST-6 Up & Limping On The Work Bench

[Ralph Mowery]

I spent most of my working life repairing or installing things, most 
electrical or electronic.

One of the first things I learned was to mark the parts if swapping 'known 
good' for the suspected ones.

The second thing was If something was working and someone else worked on it 
when it broke was to suspect it may be wired wrong or bad parts were put 
back in  by the first person and don't trust what some one else that looked 
at the problem says.  Saw two people work several hours on a simple problem 
because the first person said he checked the fuses and they were ok when one 
of them was blown.

Third was to make sure the new part is good.  Saw too many bad parts in the 
spare parts bins that were bad, even some that were new in the sealed up 
box.

I think I sent you a copy of what some of the voltages should be  in a 
trouble shooting file that Hoff published.

----- Original Message ----- 
From: "tony.podrasky" <tony.podrasky at gmail.com>
To: "Ralph Mowery" <rmowery28146 at earthlink.net>; "Green Keys" 
<greenkeys at mailman.qth.net>
Sent: Tuesday, March 15, 2016 11:09 AM
Subject: Re: [GreenKeys] ST-6 Up & Limping On The Work Bench


> Hi Ralph et al;
>
> Well, - Irv Hoff says that the LM309s can be pretty squirrely,
> and when you build the ST-6 you might have to shuffle some of
> them around until you find one that works.
>
> There is also some really weird things going on with the unit:
> I find it hard to believe that there is a wiring error - since
> this appears to have been wired by HAL - but
> the 850Hz stuff works backwards with the autostart: instead of
> going online with MARK condition, it does it in SPACE. The 425Hz
> board goes online with either MARK or SPACE. The 170Hz stuff is
> just plain old dead.
>
> I'm going to have to print out a copy of the schematic and start
> doing some point-to-point checking.
>
> I'm a GREAT ENEMY of taking something that works (my current ST-6)
> and using its parts to trouble shoot the "new ST-6": I spent 30
> years in the computer industry as a field engineer and much of
> that time repairing TWO units because the newbies, who really didn't
> understand the design and technology, were taught to SWAP things
> until it worked. That sounds "good on paper" - and certainly can
> pump-out technicians from a trade $chool - but all you need is for
> the last guy who used the kit to "forget" that he put a defective
> part in it, and turn it into the depot. Then, when the next "kid"
> signs it out, the fun begins... I spent the last 10 years of my
> career repairing what they broke - and putting up with customers
> that were cranked-off at the quality of service they were getting.
>
> UE,
> K2EAA - TONY
> NNNN
> ZCZC
>
>