Hey Chuck, Why am I not surprised that you went and measured this :). I agree that the capacitance of the lenses is pretty insignificant (by 3 orders of magnitude) compared to the bypass cap. It's

We had an electrostatic air cleaner on our HVAC system that used expanded aluminum filters. Or how about the same type of filter that is used in a range hood?

I've cleaned the oldest dirtiest (I mean dirty!) original (or as they came with) series 500 Al mesh filters. I never, when I can get them, throw the filters away... I just simply clean them. I don't

Helitrim pots cheap? Do you have a source? Thanks! Enviado do meu Tele-Movel Em qui, 15 de out de 2020 13:40, Stephen Hanselman <kc4sw.io@...> escreveu:

I have a problem with X-Y mode not working on my 468 scope. The spot it hard left and beamfinder is required to show it. Other running traces are absolutely fine. I had another discussion open for the

Hi Siggi, If you measure QP1 across its elements (12,5), you get 33.7pf. If you measure QP2 across its elements, (13.6) you get 25.6pf. Compared to the 0.022uf filter, that is pretty

Ooops sorry I read pots to mean trim pots. Still if you can replace them they will never be as stable after cleaning as new. Regards, Stephen Hanselman Datagate Systems, LLC

Replace them, they are fairly cheap, easy to change, and not noisy. Besides you could change a 10 turn into a 25 turn and make the adjustments way less twitchy. We have seen a significant

Hi Alexandre, You could try squirting some Deoxit or Servisol into the pots via gaps near the connectors. You might get lucky and enough goes in to do the job. You need to turn the pot from end to end

Hi, What personally do, and it works fine for me, is I remove the knobs, and let isopropyl alcohol drip inside the pot from the front, between the shaft and the casing. And I keep turning and

Greetz All! My FG503 got dirty pots. I need to clean it, but they seem to be sealed. Is there any technique to clean these pots? Thanks Alexandre -- ---8<---Corte

Thank you! larry

Since I posted, I've done more searching, and yes, there are several companies that sell the aluminum filters, mostly for cooking exhaust fans. I had not thought about coating the filter with

Check this capacitor C582, but since you have disconnected the HT from the secondary of T550, I would concentrate on the primary circuit and find out whether the oscillator constituted by Q552 and

Hi Mark, Of the things that tend to be overlooked when debugging VT circuits, the level-shifting neon bulb surely ranks high (here, that's B167). If the bulb no longer fires, the loop breaks and the

Mark the first thing I always suspect is causing the problem is a tube. Rightly or wrongly. But is the easiest check to make. I turn out the lights (keep flashlight in hand) and look for a tube that

Gregor, I read somewhere online about R1853, R1854, R1871, R1872 and R1880 are prone to opening or going high causing focus problems. The originals are 1/4W. The suggested replacements should be

John, Looking at page 5-8 indicates mine is with the high voltage at the plate of the Miller tube V161A. Grounding the grid did make the difference in the paragraph; stuck in run up position.

Sorry Mark I forgot to ask if you have checked all of the power supply voltages. The sweep is especially sensitive to these voltages being incorrect.

Hi Mark. Sounds familiar. I have been fooled many times by the famous Tektronix sweep circuit. So if I sound like I am a bit dense please forgive. First, are you sure the sweep circuit is what is