It may have a PSU problem as Chuck described. However, if the 100V supply is being loaded, this sounds like the CRT HV transformer problem typical of the older brown encapsulated transformer design.

I got 0.07 USD for a class action lawsuit on bad motherboard capacitors back in the day. Probably related to many different products. 73! Mark KA6WKE Website: https://www.ka6wke.net Live Stream:

Roy, I got very lucky a couple weeks ago and scored a basically pristine 7104 and it's intended plugin complement at a .gov surplus auction for a very good price (all of the above for $125). It is

I don't know what shape your 576 is in, but I have found many with bad 5V filter capacitors. They suddenly go open circuit. They are the Mallory FP style, and the internal aluminum strip that

I have not had any replies on the TDS644A power supply problem. I have my repair log for the last repair if anyone is interested. It is not a simple power supply. While troubleshooting I needed my Tek

We don't offer the re-bake process on U800's any longer at Sphere (because Toru in Japan does not do it any longer). The actual root cause of the primary problem with U800 is as follows: The modified

George and DW Definitely a 170uF Cap. I would check the ESR on that old cap very carefully, if it checks "good" for capacity, ESR and ripple, leave it alone. I just finished with a 577 and the

Think of a CRT's electron gun as being like a machine gun. Just like a machine gun fires bullets at a fixed continuous rate, so does an electron gun with electrons. Let's imagine our electron gun

Hi Dennis: We have 2 7104s... and occasionally I see one for sale, and the picture of it usually shows it operating with the amber "limited viewing time" indicator illuminated. I'd only pay the

You should be fine. 20% above 200 volts would be 240 volts. BTW, the schematic shows the value C744 as 170 micro farad. George KD6NEW

I would stick with what you have, maybe it's time to do a little service on it, sometimes you need a dual supply or even 3voltages it's rare though. I should have done more resurch on this before I

The condensers you mention were a worldwide scourge. Many millions of them were made when an angry employee stole the electrolyte formula from one company and took it to another. The problem was the

The dim traces on the vertical part of a square wave is normal. This is due to the speed which they are "drawn" on the CRT face. The faster the rise time of the trace, the dimmer the trace will

Hi Siggi, While the models I mention do have aluminum SMT electrolytics on the front panel, I have not seen any that were leaking. I suspect that the leaking caps on the older models were a quality

The General Radio part of the IEC site has many old GR catalogs. They will help identify the connectors used and those available as parts. GR used a couple of variations of binding posts, mostly

I've carried the 500s and 7000s, for long distances occasionally 1Km plus, and frequently carried them a couple of hundred meters.. and lots of times carried them 10 to 20 meters, from lab to lab,

unless it is cold worked (like stamping it?)... and then it develops a magnetic response. The strength of which [compared to stainless numbers that are magnetic]… I guess... depends on the amount of

I found a 1001A that I though had a BNC output connector; but, it was an 874 to BNC adapter, inserted into the front panel 874. I have some GR units, mostly older than 1950, mostly audio, 600 ohm

I'm slowly going through my 2235A scope, replacing the Schaffner line filter and the RIFA capacitors on the Pre Regulator board. The RIFA caps were visibly crazed, so I'm glad I'm replacing them

I have a Tektronix 577 curve tracer and I am recapping the power supply board that is located at the rear of the instrument. I am looking at replacing C744 which is a 250V 1700uF capacitor. I found a