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Products => Test Equipment => Topic started by: munorc on January 01, 2019, 04:40:36 pm

Title: Tek 453 MOD703k
Post by: munorc on January 01, 2019, 04:40:36 pm

I have a Tek 453 scope that I have had on my bench for a few years.  I never paid much attention to its oddities until I started looking through the manual as a reference for another 453 that is missing the Variable/Cal knob for the sweep control. 

This 453 does not have a side panel and the calibration loop is on the front.  Looking closer, I see it is marked MOD703K.   I find a few scattered references that it was a version made for the USAF and has an 8 division high screen instead of 6.

Any more details available?   

Title: Re: Tek 453 MOD703k
Post by: particleman on January 01, 2019, 06:42:23 pm

Nice oscilloscope. Here is a good link on the changes in MOD703K. https://groups.io/g/TekScopes/topic/7631583#8508

Title: Re: Tek 453 MOD703k
Post by: munorc on January 01, 2019, 06:55:33 pm

Thanks. That is more info than I had found previously.

From that post:

703K: Added SAWTOOTH OUT on the rear, CH1 OUT moved to front, A and B
gate added on the rear, Calibrator Current Loop added on front and 1V
CAL connector moved, Added TRACE FINDER to the front, Added X-Y
position to the HORIZ DISPLAY switch, Deleted RESET light, Added new
functions to the Delayed sweep triggering switch.

703H: The 453 Mod 703H is a Tektronix Type 453 Oscilloscope
equipped with a larger, 8 x 10 division CRT, with risetime-pattern
internal graticule, an added SAWTOOTH OUT facility, increased CH 1
OUT amplitude and an all-solid-state HV supply. The side panel and
certain low-usage controls, features, accessories and sweep ranges
are deleted. Performance limits and test procedures are changed to
reflect the specific requiremnets of MIL-0-9960C (USAF).

As alluded to in that thread, the one I have has a serial number prefixed with "B". 

Title: Re: Tek 453 MOD703k
Post by: munorc on January 02, 2019, 11:21:19 pm

Hmmm, the other 453, with the missing knob, is a MOD703K as well.

Attached is a picture of the scope with the missing knob.  Since there is nothing to attach to, I assume also missing is a shaft that would attach to a pot at the back of the switch stack. I looked inside, but it is pretty crowded in there.  Is this held with a set screw or some other means?

Title: Re: Tek 453 MOD703k
Post by: munorc on January 03, 2019, 05:56:48 pm

Would the question regarding teh missing knob be more appropriate in the Repair forum?  New hear and I did not notice there was a separate section.