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In response to Keith's #5 statement, I have one original Tek CRT shipping box fitted for rectangular CRTs, that came with some kind of monitor tube in it that I picked up for free long ago. I think I

@Keith Thanks for the post, the tale is a good read but in the end it all came good, so I'm going to try to remain an optimist and hope for an eventual successful outcome MostlyHarmless

And swap them is exactly what I did, I first swapped the outputs from attenuators to see if it was them first and just worked back over till the fault was shown on ch1, and the CCD was the culprit,

FWIW, I have been down this trail - all the way, and within the past 3 years. Some observations that may help you - because it looks like you are doing the very same things I did when my 575 showed

I suspect it may be because the fT of my transistors is too high. The MJE15030 has 10 times the fT of the TIP41C (30MHz vs 3MHz). This could explain why the MJE15030 is able to oscillate at 1MHz while

C944 was ceramic, but pulling it out revealed that it was leaky and high ESR. I swapped it out and the power supply seems to work better now. It now runs off mains when the potentiometer is turned

emissionlabs: That sound very plausible. It's a pity, because the Tektronix knobs are the best looking I have seen on any instrument. Mine are now beyond repair, at least the Variable Collector

Hi Eric please let me know if you do have one MostlyHarmless

Ok, Tek did a lot of "referenced" designs.? In the scopes, typically a -50 volt supply is fully adjustable, and the other supplies depend on resistor tolerances to get the right voltages. If the -22

The knobs crack, because the inner metal part is just pressed into the plastic, while of course it has to be a little bit too large, or it won't stay in. So on the long term, the knobs will crack.

@Harvey Measured voltage across 0.33ohm R624 = ~0.35V. So ~1A. Seems normal. One thing I learned reading through the circuit description is that 5V supply is referenced from the -22V rail. Would

@Hakan, thanks for the info, yeah but it seemed to confuse Eric on the part number(the 465 having a rectangular CRT unlike the 5 inch round CRT I would like to buy) but not to worry it seems he may

I had JLCPCB make some small parts out of black nylon for one of my plugins. They did very good work. Barry - N4BUQ

Have you already checked/replaced C940 and R949? I assumed yes but not sure. What is the voltage across R949 (0.51 ohms)? Measure on a DMM, not scope, then calculate the current. Does it agree fairly

Adam, Thanks for posting this and for the stl file. The Tek part number is 348-0075-00. It seems like the rear feet (guards), are always broken. I initially printed a prototype on my home printer

Obviously you didn't understand the info. To clearify... 1: The purpose of the other listed instruments was to help you find another donor which use the same CRT. 2: The purpose of the different

I meant that I get 1.9V on the bottom of C943 with 42 volts (and with the potentiometer turned a little). It looks like the regulation is working, but it still doesn't start up properly. To start it

Here are my measurements: Input voltage: 39.57V Q944: C = 10V, B = -0.3V, E = -1V Q939: C = -0.3V, B = 33.41, E = 33.91 C943 negative: -1.9V Q938: C = 5.58V, B = 33.28V E = 33.90V C942: 33.83V

I will check the stock again tonight I do belive I have one of the T0520-31. I will let you know this evening. Eric wrote:

Forgot to mention the apparent brightness of the trace in the picture could be a camera artifact, being more sensitive than the eye. You'll have to judge the actual brightness. Also,having the CRT