[time-nuts] Re: TSC5120A

[Bob Martin]

Tom,

  It is exciting to see that people like yourself are improving on 
the design of the TSC5120A.  When I was the EKG designer for HP
Medical we had enormous resources for wringing out designs for
reliability and performance under varied conditions. Not so much
for a small company like Timing Solution where judgement and
experience are crucial to success of any product. The TSC5120
took years to develop with limited resources. At that time
we had other irons in the fire such as the Master Timing
Node for the National ignition Facility, the NASA Deep Space
Upgrade, Loran and a family of 1U distribution products to name a few.

FOR THE RECORD - I did not design the TSC5120.
I did design the backplane and some ancillary boards that went
into the unit.  The real designer was a brilliant engineer named 
Wayne Solbrig who is deceased. Of course Sam Stein sat in Olympus
and watched over everything that went on at TSC. I'm not a Time
and Frequency person. As Director of Hardware Development and an 
active designer, I was just a bumblebee flying around under Sam's 
direction.

Hank Ball, now retired (but still a true Time-Nut), redesigned the 
front end to reduce susceptibility to input damage and improve 
performance after Wayne left Symmetricom.

I hated that little fan from the day I saw it. It ran at high
speed and I worried that it might affect measurements. It was added
as an afterthought to reduce the internal temperature. I'm happy to 
see that you have improved on that design.

It would be really neat if Microchip released the TSC5120 design to 
a bunch of Time-Nuts! The technology is old enough so that I doubt
there is anything proprietary left in the design.

My condolences on the loss of your lab in the Marshal fire.

Best,

Bob Martin

Message: 3
Date: Sun, 6 Aug 2023 18:17:08 +0000
From: Tom Knox <actast at hotmail.com>
Subject: [time-nuts] TSC5120A and 5125A heat issue
To: "time-nuts at lists.febo.com" <time-nuts at lists.febo.com>
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Hi Bob;
A great product you designed. I wish Microchip would have continued 
evolution in that (standalone instrument) direction.
After many hours researching the heat and time-out issues on the 
5125A and 5120A I found the solution was adding a larger 60mm fan 
and an airflow deflector near the front panel to create a circular 
airflow through-out the instrument. There are a number of additional 
details to this upgrade but It completely solved the issues and the 
final mod had no negative effect - perhaps actually improving 
performance by reducing measurement artifacts. To accomplish this, I 
tried over 10 fans, and in the final REV placed the fan outside the 
chassis using gaskets and neoprene washers to reduce electrical 
noise and isolate mechanical vibration. At the time I also added an 
external monitor output.
Another upgrade that helps protect the 5120/5A series from front end 
damage ( I believe is standard on many later 5120A/5125A analyzers ) 
are DC blocks on the inputs. I did this differently than Microchip 
by adding metrology grade stainless TNC to SMA front panel 
connectors and installed Mini -Circuits BLK-89-S+ DC Blocks directly 
to those adapters with SMA-m to SMA-m RA cables between the front 
panel DC blocks and P/N module inputs.
I also added additional RAM doubling the original (256MB?) to 512MB.
I attached a few photos.
All these minor improvements made an exceptional product better 
achieve its full potential.

Feel free to contact me for details.

Enjoy;
Tom Knox
SR Test and Measurement Engineer
Phoenix Research
4870 Meredith Way Apt 102
Boulder, Co 80303