Don`t keep us in suspence Jake, how are you going with your 475? [I have one of these too] Cheers!...................................................................Donald

Is the fse on the main PCB at the back left blown? If so, it is almost certain that the Tantalum capacitor associated with this circuit is shorted......................Donald Collie <https://www.avast

I purchased several of these attenuators from Sphere Research. They were available used but good, and new.Cheers!...........Don

Thanks Leo, and Jared - yes a fan would make all the difference. Unfortunately the gentleman concerened no longer makes the 22xx Volts/Div knobs, so I`m not sure exactly where to get two of those knob

Thankyou Tom, i`ll drop him a line..................Don

I only really need the clear plastic skirt on this knob [minimum], or two complete knobs [maximum], as I can probably repair the other one, which has a cracked skirt. Willing to pay for these. Probabl

The FREON, which is unobtainable as it causes ozone holes in the upper atmosphere, is used as a high performance insulator. The probe is filled with it., or would be If you could get any - it`s been o

Hi Lorn, I have a 475, which is similar. I`ve noticed that it needs the covers on, otherwise it will pick up hum and either produce a triggerable trace, about 2 minor divisions high, or a thick trace

Not sure if this will help or not , but I couldn`t turn down the brightness on my 475 - turned out to be leaky dc restorer diodes, which in mine are HF and HV diodes. Good luck!.......................

Hi Manfred! I`ve just finished a 475, which is similar. It had a similar problem which was completely cured by replacing a transistor in the sweep circuit. There are 3 sweep circuits, so you can swap

Looked at the photos - yes, that`s about as sharp as mine goes. Cheers!...............................................................................................................................Do

Thankyou gentlemen, that`s exactly what I wanted to know. Cheers.......................................................................................................................................D

Replacing the defective transistor in the Z - Amp, with a more suitable high speed type improves the problem, but it`s still there. This may be normal for this `scope, or it might need further work. W

I found a dead transistor in the Z Amp, which prompted me to check all the Z Amp transistors, but the rest are OK. My 453A does this on the fastest sweep setting, but only half a major division, and m

When I look at a 100Mhz signal, instead of starting at the left of the CRT graticule, the trace starts at the 2nd major division - 2 divisions to the right of the Left Hand Side. Is this normal? This

I`d steer clear of even testing the tunnel diodes - they`re darn near unobtainable- leave well alone. You have two `scopes, why not use one to trace the trigger signal on the other, and see where the

Apply a small fan to the transformer? <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virus-free. www.avg.com <http://www.avg.com/email

I use hot, dry, moving air, blowing past all parts of the instrument. I like the idea of keeping it hot for a full 48 hours, to drive water out of the cracks. I got impatient once, with a 5245L - when

Sorry Dave, the blurb was, of course, meant for Felix. Cheers!...........................................................................................Don C. <http://www.avg.com/email-signature?utm_

Hi Dave, Sphere Research Corporation have a document available from their website by Tek, on how to troubleshoot their `scopes - you might like to read it. Don`t let this `scope beat you, is the corre