Tektronix AWG2021 - cant remove cabinet, amplitude issues - Page 1
Forum section: electronics / testgear

author: TAMHAN
author_rank: Frequent Contributor
timestamp: December 02, 2015, 09:10:54 pm
content: Hello Folks,the first part of the gadgets SWIMBO ordered for our lab have arrived. And we have a small problem already: our Tek AWG2021 - it was an occasion, as the swiss would say - has arrived. When we took it out of the box, we heard a screw rattle around the box...which we wanted to remove. But alas, we could not open the case even after trying for two hours. Yes, all screws - including the cabinet one on the left side - were removed, and it even slid open a bit.SWIMBO believes it is due to the dents in the cabinet. I attached a pic here...this ex alcatel unit must have been kicked hard, leading to a deformation of the fan cage and stuff. Taking nit apart required tremendous amounts of energy - I had to "rig" the screw driver machine as shown in the picture three in order to get to the screws, and needed the maximum power level to even be able to turn the screw.Post 1/2, 2/2 comes soon

author: TAMHAN
author_rank: Frequent Contributor
timestamp: December 02, 2015, 09:20:09 pm
content: Post 2/2After trying to open the thing for three hours - the styrofoam at the bottom in one of the pics is a rig SWIMBO built to protect the BNC jacks - she decided that "private militia trained officials and other cowards" should leave the lab. Plugged it in, and it ran and passed SelfTest with no issue.When I came back, it was rigged up "probe to probe" as shown in the pic. I immediately fired up some waveforms...and saw that the amplitude is consistently, way off in both 50 Ohm and 10 MOhm modes. One Volt of "indicated" tends to lead to about 150mv of "measured".Now, we have a few questions:a) is this reduced amplitude normal? Or is the generator defective?b) do you have any idea how to get the cabinet off if we ever need to (hopefully not)c) Our unit was built in November 1994 by Toshiba. Do you think it has the old caps?

author: TAMHAN
author_rank: Frequent Contributor
timestamp: December 02, 2015, 09:21:59 pm
content: And finally, the amplitude pics.

author: free_electron
author_rank: Super Contributor
timestamp: December 02, 2015, 09:58:54 pm
content: if i remeber right : the handle needs to be removed. pop the circular disks in the hinge. there is a screw under there , or a nut.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 02, 2015, 11:57:55 pm
content: Quote from: TAMHAN on December 02, 2015, 09:20:09 pmToshiba? You mean Sony?3Vp-p should be 3Vp-p into 50 ohms. Something is not right, possible operator? What's up with the two scope probes back to back?Handle is right....The old caps? Yes, it was built in 94, it has old caps in it.These are pretty nice units for their age.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: December 03, 2015, 05:48:41 am
content: Hello Folks,thank you so much for your comments, I am very happy.Re the handle: now that is very odd. The official service manual had us here...as it shows the generator cabinet being removed with the handle on. Either way, I will try to get the handle off - what do you guys mean by popping the disk hinge? Press it in like on an Iwatsu? Strangely, we were able to slide the cabinet off approximately 10 centimeters before it stopped budging...Update: tried to press the handles in to move the handle. It doesnt budge, so I cant even move it from its "top" positionRe the scope probes: we currently dont have a 50 Ohm cable on hand, and had to rig something to be able to see its output.Re the Toshiba: no joke, in ours, there was a label stating made by Toshiba (!). If I get to open the thingy again, I will shoot a pic!P.S. Yes, the GUI and handling are really impressive...

author: TerraHertz
author_rank: Super Contributor
timestamp: December 03, 2015, 08:13:14 am
content: I think those handles are the type where you pull the pivot OUT to unlock the detent. The plastic has short molded pins around the periphery that engage in holes in the case.Maybe you are supposed to pull the handle pivots out at the same time as sliding the case off? So those pins and whatever is at the center of the pivot clears components of the scope frame.It's possible those dents may *also* be jamming it.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: December 03, 2015, 09:12:18 am
content: Terra, nice to hear from you - a familiar face from another threadI figured out that you need to pull out to turn literally as I read your post, big thanks. Sadly, I still can't remove the handle...I can just move it to a more convinient position.If it really is these dents, do you have an idea what we can do? SWIMBO already tried all kinds of mechanical trinkets including a chefs knife (!!!) - to no avail, after moving for about 10 cm total, the generator declared "no more moving".

author: dan3460
author_rank: Frequent Contributor
timestamp: December 08, 2015, 03:57:29 pm
content: I'm not an expert but all the Tek handles that I have seen do not need to be removed to get the cover off. Many of the handles, the screw to remove them can be only accessed when the cover is removed. Besides on the manual there is no mention of removing the handles before removing the cabinet.The cover will need to be pry off. I would do is using a pair of locking pliers and a big screwdriver, grab one side of the cabinet from the back and use the screwdriver to push the frame forward. Then grab the other side and repeat until you get the cover off.The metal of the cover is pretty think, it probably took a substantial hit to make that dent.good luck.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: December 09, 2015, 11:56:14 am
content: Hi Dan,thank you so much for your feedback.To be honest: according to SWIMBO, the thing will get about 6 to 10 hours of use a year. If it lives for two years, it has written itself off. So, SWIMBO - who will also work on it - suggested that, as we got the screw out, we will simply leave the unit be for now. If we try to force it apart, we could really fook it up...What would help us would be some info on whether the AWG2021, if built in 1994, contains the "black widow" caps which leak out like in some of the older TDS500 and TDS600 scopes. We know that the AWG2020 has them...but that one is an older model...