[time-nuts] Re: HP 3561a Service Manual

[Richard (Rick) Karlquist]

I was working for HP in 1983 at the division that produced the 3561.
In those days everyone had "terminals" that were used to remotely
log in to shared computers.  These terminals had a bunch of PC
cards with gold plated edge-card connectors.  It was SOP that
one's terminal would stop working periodically, and the fix was
to simply unplug all the boards and then reseat them.  This
almost always worked.

If you got nearly 40 years out of your connectors without a
problem, you did well.  I too have a vintage 3561 that still
works fine.

Rick N6RK

On 11/13/2021 3:42 AM, Norman Reitz via time-nuts wrote:
> Hello !
> Working 🙂🙃🙂🙃
> I opened the device and am really impressed with the quality of the construction. 30 years old, no gram of dust! It looks like it has just left HP 😍. I have cleaned the contacts of all boards and want to briefly show you the result. I will use the service instructions to calibrate the device. The first milestone has been achieved. More luck than sense again. Many greetings and many thanks for your help.
> Norman
> 
> 
> 
> Gesendet von Yahoo Mail auf Android
>   
>    Am Sa., Nov. 13, 2021 at 6:27 schrieb Dan Rae via time-nuts<time-nuts at lists.febo.com>:   Norman,
> 
>   From the code 0 7 26, if there is just one faulty RAM IC you will see
> down the bottom of the screen a RAM hex number from 0 to F. On page 6-59
> in Volume 1 you will find a list of the IC numbers that correspond to
> those RAM numbers.   However since you seem to have an additional Error
> Code 31 and the full list of RAM numbers displayed it is likely to be
> more than a simple one IC failure. 31 indicates RAM refresh test error,
> if that means anything to you, I'm a bit lost frankly.  It might be
> worth checking the board connections...
> 
> Good luck!
> 
> Dan
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