Tektronix TDS7104, thinking of buying...

[SpeedD408]

Hello,

I’m in the marker for a scope.  I’ve been watching the EEVBlog videos and looked at spec sheets and trying to figure out the one I want.  I’ve been looking and almost pulled the trigger on a Rigol DS4032 as TEquip had a special going (free 500mhz and serial decode upgrades) I didn’t do it as $2700 for a hobby is a lot.  So started looking on auctions sites and the old Tektronix TDS7104 looks very interesting.  1 GHz bandwidth, 10GS/s, 4 Ch, but looks to be 10years old and it runs Win XP so it is slow to boot up and probably weighs 50 lbs and is large.  However, I don’t think I can beat the features for my budget but I’m having a hard time justifying that kind of money on 10 year old gear which could die at any point.

What is the normal lifespan of this unit? 

I read the thread on the high failure rate of the Maxim DS1245yp-100 , but that seem to be the only negative.

Anything I should know before forking out the cash?

Thanks....


Sent from my iPad using Tapatalk

[TheSteve]

What are your requirements? Newer scopes have decode options which are very nice.

[nctnico]

One of the problems with older high bandwidth DSOs is noise. That is not just due to their higher bandwidth but also the noise of the ADCs is much higher. I wouldn't recommend such a scope because it will be near useless for low frequency work. You'll have to turn on high-res or averaging all the time which come with their limitations like not being able to use peak-detect at the same time.

For this reason I have multiple oscilloscopes. I have a GW Instek GDS2204E (200MHz 4 channels) for low frequency work. It's noise is just above 1LSB of the AD converter so you get a (near) flat line if you short the input and it is perfect for working on analog stuff. For high frequency work I have an Agilent 54835 which (when uphacked to a 54845) is pretty close in specs compared to the TDS7104.

[SpeedD408]

My requirements are not very high so I know I have over kill on the brain, but I do simple retro computer repairs and I am considering taking that to the next level as well as looking into pinball/video game board repairs.  I used to do Apple II, pinball/video arcade repairs back in '82-86.  So I'm brushing up on my skills.  Is a 1GHz scope required for this no.  However, if a new 200-350Mhz is the more than an older 1GHz scope with 10x the sample rate I figured it was worth looking at.

Noise...  I hadn't considered that.  I would have though that the ADCs would have been dead quiet at lower frequencies. This is good to know. 

Decodes - UART/RS-232 would be most used, then I2C and maybe SPI.

Thanks for the help.