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Dennis, Is there a link to this listing? I am certainly interested. I actually have two of the boxes (actually, mine are walnut, according to the label on the bottom) and am only missing one or two of

Hi Max, We (TekScopes) are incredibly fortunate to benefit from the tireless work of Kurt Rosenfeld who has created and maintained the most astounding collection of information about Tektronix

Last few days I just read everything in manual from start to end, sometimes backwards, to try to understand as good as possible how this scope works (CPU and display board). Siggi was right about

I know I was just kidding. I also had my share of funny auto correct stories. The goal is to find if sweep trigger is not coming (no gate) or sweep trigger comes but sweep doesn't happen. DC levels

Just use good sockets!? I usually socket the ICs in all my projects because I hate desoldering them should the need arise, and I try to use machined sockets where possible. -Dave

Trust me it's the phones auto correct turning opamp into obama :) I think I had the timebase measurements AC coupled and there was no change in level. I haven't checked the DC. I will do that tomorrow

Agreed, but I should point out again that I have seen 2 or 3 gold plated GR connectors that are not 125 ohm, and one of my 519s has no gold plating at all on it's connectors (and they are 125 ohm

Hi Charles and Dave and Sean, The RATIO of the diameter of the INSIDE of the OUTER conductor to the OUTER diameter of the INSIDE conductor and the dielectric constant of the medium in between the

Please no politics in the group :) It looks like your HV supply is in good shape now. With these new measurements observations are pointing to faulty diodes. Flat at what voltage level? Compared to

The UF4004 vs BAV21. BAV is same speed with 50ns recovery but 250V, UF4004 is 400V and higher current at the same speed. I have BAV21 in stock, I'd have to order in the UF4004s

+75 to +110

The HV area is now lot better I have cleaned thoroughly the entire area with IPA and now I have steady -2950. This also resolved the problems at the Obama where now I have basically zeroes at pins 2

While surfing the web, I came across this link entitled "Tektronix CRT History" by Peter Keller. It may be of interest to the group.

What voltage range do you see at TP1665 when you change grid bias. No need to re-measure, just ballpark numbers you remember. Especially the sign, positive or negative voltage. Ozan

It is a bit low in capacitance but it is not the reason for the failure. However, I would replace it anyway since you removed it and it was stressed by high voltage. Ozan

I thoroughly cleaned the entire HV area with IPA and now the 2950V is steady while before it would drift slowly down to 2800 and even further The grid bias changes the voltage at TP1665 but does not

Behavior of your 485 is changing over time so some of these comments may not apply to current state of the scope but here is my feedback: This means the regulation loop (U1624) thinks HV voltage is

Well, I'm glad it wasn't my design that was in error. :D I'm interested in why the opamps popped too, I wonder if there is a bodge that can be added to existing units to protect the opamps from this

most likely the peaks on V+ ( or inputs)? exceeded max for the 741...had it happen a lot on equipment in implanters....we also had walking wounded which would sometimes work and well sometimes do

Ozan, Thanks, that makes a lot more sense now. I will run through and check all the connections from the LV regulator to the other boards (a nice, easy check that can be done with the power OFF). I