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 be.
The faster the trace speed, the dimmer the trace.
It is like painting with a spray can.
If you hold the nozzle down and paint a horizontal line then quickly paint a vertical line, the vertical line will have less paint on it per unit of length than the horizontal line.
Glenn
toggle quoted message
Show quoted text
On 8/21/2019 1:43 AM, Ed Pavlovic wrote:
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 before they failed like the ones in an old computer PSU I have.
Issue I'm having is the vertical traces are very dim compared to horizontal traces. Most noticeable on a square wave, but if you introduce a horizontal element, a sinewave or sawtooth pattern, the trace looks normal.
I'm waiting on parts from Mouser to replace the failure prone inlet caps with new ones, so I'm unable to check voltages and ripple at the moment.
Is it just an issue with the width of a vertical trace affecting the brightness on the screen, or is there maybe a deeper issue going on here?
Thanks
Ed Pavlovic
KC9MMM
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
