That is interesting as I had a feeling that the zener might be bad, but I haven’t checked it yet. On the to-do list. Many thanks Simon

I taught my daughter the concept of how you become a drunkard, i.e. one drink at a time. I once asked people why I needed a fourth scope. There was only one justifiable answer: you must have four

Chuck, Yes, it SUCKS! When I heard that glass tinkle, my heart sank. If this was an old beater, it would not be so bad, but this is a very nice scope. I suppose that a good parts scope will turn

Ok, you are almost there. There are two things at play at the same time with the intensity grid function. The first is the DC restorer, which you have checked. It translates the voltage output from

I have got around to operating my PS 503A on a known-good TM504 Mainframe and it works fine. I also checked it on a known-good TM503 mainframe using my Dan Meeks extender; again fine. I was looking

Not to get in the way of this, but you could also just check the individual voltage drop between the Drain and Source leads to their origin and find out if the connector is actually causing any drop.

Tom, Laughing here at reading this. Almost exactly how I got into the same predicament here. Some people say you smoke crack one time and you are hooked and people like us fix one scope and we are

After some long posts spanning over 2 threads, trying to figure out why the DC503, then the DC505A did not display anything else than just a randomly placed single “0” at any one time while

Toby, Yes, I found that one. Too rich for my blood. I will just lurk around until I find a parts scope. One of these will turn up sooner or later. -- Michael Lynch Dardanelle, AR

Hi satbeginner Not yet I will do it tomorrow and check if that improves the situation. Thanks Saroj

I tested all the transistors in the Z-axis amplifier and all were OK. The amplifier puts out a square wave which varies from 0 to 35 V with the intensity control, but the beam was still too bright at

https://www.ebay.co.uk/itm/254685390375 Is this produced by one our members? David

I have been successfully using an HP 4815A for in-circuit ESR testing for more than 20 years.

OK so here is the good news update, a massive thank you to Andy Warner who sent me a new pair of ROMS, both Roms had gone, but so had U2092, I managed to get a MC68B02 for only a few UK£'s to test,

Hi Saroj, With respect to the voltage drop after a while, did you already removed the Molex connector from the FET? Over the years, the FET, so also the Molex, worked at temperatures around 70

Ok.. Since the only difference between the extender and the connector inside the mainframe is “Option 12” connected to pins 27A’s and 28A’s, I removed all the 6 coax from the back of the

Worth noting though, this mainframe has Option 12 installed. But there is nothing connected to the BNC’s at the back. And all 6 of them have their leads go respectively and independently to each

You probably mean 24A/A Yes, this is exactly what I have. However, on my extender, none of these are connected. Only every pin, but 6B, from 1 to 13 are. And, according to another post, that seems

FWIW: The C stands for commercial grade, which has to do with the operating temperatures and possibly bias and offset values.

On Wed, Aug 12, 2020 at 02:14 PM, <sdferg7@...> wrote: Looking at your middle picture, it does seem that a good clean around the IC socket would be a good idea. It looks like Q555 may have