Products > Test Equipment
Conversion of 500MHz TDS744A to 1GHz TDS784A
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Tantratron:

--- Quote from: Galen on January 07, 2020, 05:52:53 am ---
--- Quote from: Galen on December 20, 2019, 06:31:48 am ---Thanks nctnico. I will need a few days to try this as time tied up these days.
The TDS580C published with the FW5.2 as stated in the tek document, so maybe the FW5.0 doesn't have the ID code for TDS580C.
But anyway, I will have a try.

--- End quote ---
After I upgraded the firmware, the banner shows 'TDS580C'.  so shorting R1064 is right for TDS580C.

--- End quote ---
What 5.x firmware version did you flash to have banner showing TDS580C
Pete2:
I just got a 754A from Ebay. Paid too much for it because of postage and import VAT but that's the way it is. It is faulty, the infamous relays + dim CRT but at least I can retrofit an LCD if needed.

Anyway I found this topic and was considering the upgrade but I have no way to calibrate it so maybe I'll skip it for now. Also I am looking at a 754C and I assume it can have the 2M option. Is  this true? But I have to have a correct Acq board or can all of the C models support the high memory option? Any other reasons to choose 754C over 754A?
Tantratron:
Hello Pete2,

Transforming the acquisition board of a 754 into 784 requires removing 4 capacitors and lengthy re-calibration. I assume but could be wrong that if you change faulty attenuator relays will introduce some parasitic capacitance so you'll be obliged to re-calibrate the 754.

In a few words, the TDS754A or TDS784A acquisition board is the same HW as the C series, the only difference concerns logic CPU board. The A runs with 68020 whereas the C serie runs with 68040 so it is just hacking process.

What country do you reside, how does it work with intra-european import tax ?

Albert
44kgk1lkf6u:
I converted a TDS540D into a TDS580D.  It came with the jumpers R1061, R1062, and R1063.  I removed them and added R1064.  I removed the capacitors.  Then I ran signal path compensation and internal diagnostics.  Now the start-up screen shows TDS580D.  My firmware is v6.1e.  Unlike the TDS540C, I suppose any firmware that comes with revision D will be new enough.

Results.  The fastest time base went from 500 ps / div to 200 ps / div.  The fastest sample rate for a single channel went from 2 GS / s real time and 100 GS / s equivalent time to 4 GS / s real time and 250 GS / s equivalent time.  10% to 90% rise and fall times are about 250 ps at 200 mV / div and about 355 ps at 100 mV / div after the hack as measured with the measure function.  Changing the vertical scale only seems to affect the rise and fall times when it comes with a relay click.  Switching between 50 mV / div and 100 mV / div does not cause a relay to click.  The edges are about the same in those vertical scales.  Likewise the edges are similar at 200 mV / div and 500 mV / div.  To measure these I used an Onsemi NB7VQ14M CML gate to generate the square waves.  I added a 6 dB attenuator so that the waveform fits on the screen at 50 mV / div.  For coarser scales the attenuator did not seem to make a difference in the bandwidth.
David Hess:
Bandwidth of the 580D and 784D decreases from 1 GHz at 10mV/div to 500 MHz at 1mV/div.
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