[SOLVED] CRT (osciliscope) BWD 525 showing multiple horizontal lines

[betwixt]

Well done Joe!

Before worrying about the scan being too short, check it isn't just displaced too far to the left.

Brian.

 

[jdimeglio]

:lol:

Yea checked that. And im tripple checking everything i post now.

Adjusting the x position to the left - moves the entire scan to the left side and "off" the screen (perfect), however when i move it to the right it clips.

It clips 2.5mm short of the end of the grid - let alone scrolling off the screen.

So my max horizontal defection is from off the left side of the screen all the way to -2.5mm from the right edge of the grid.

So the plan is to check RV100 & R101 & R102.



Cheers

joe

 

[betwixt]

RV100 A and B will be the front panel and preset horizontal position controls. They may be the problem but before going further, check the power supply voltages in that area are correct, especially that the +15V, -15V and -14.5V rails are at those voltages. Any imbalance between them will shift the scan sideways. It might be worthwhile switching to external X input and applying a voltage from outside to check if the dot is actually capable of being moved further to the right. It would help to decide whether you are looking for a voltage imbalance or the X amplifier is clipping.

Brian.

 

[jdimeglio]

i've checked the voltages with a multimeter - and after some minor adjustments - they're perfect. Adjusted the -15v rail also adjusted the 15 and the -14.5. Also adjusted the 100v. All good - i swear.

....but i think thats whats happening - its shifted the display sideways. Instead of the right edge being somewhere off the right edge its on the screen.

The ext. input is a good idea - i'll have to mock something up for that..

Actually this has been like this since i bought it a couple years ago and be nice to resolve it.


(thanks for the input - i'm feeling the love)

 

[Pedro48]

Hi Joe,

I too have a BWD 525 scope, that is working properly (aside from a smelly problem with timebase B). In the future if I can assist (voltage measurements to compare etc etc).. happy to do so ...Glad you have yours working again..

Peter

 

[jdimeglio]

Thanks Peter,

Thats awesome - same here - happy to make some measurements too.

PS: i might actually call on that favour ;-)

Im currently having another issue with this CRO - which is ensuring my horizontal trace makes all the way to the right.. Theres another thread/post open at the moment that im working through..

cheers

Goto love this forum and the people on it

kind regards


Joe