Schematic for Leader 508 Analog Oscilloscope

[Inquisitive]

I have a single page of the Horizontal Amp section of this scope, but there must be more than just one page. Does anybody have or know where I can find a complete schematic for troubleshooting purposes?

Thanks in advance for your help!

 

[Reloadron]

The attached manual is choppy but from what I can see the last page is the horizontal out section to the CRT pins. That what you need?

Ron

 

[Inquisitive]

Thanks for the quick reply. That is the same manual I have.

I'm having trouble with the calibration section. I get a dirty(jagged) vertical and horizontal square pulse wave, on one channel only. I was hoping to find the pages covering the calibration circuits, as they are not in the 29 page version. I have ruled out the probes being bad. They work great on the other channel. So, it must be internal component failing in the scope someplace.

 

[Reloadron]

You may want to check the V/Div switching for dirt? Troubleshooting like this goes well when you have another scope to troubleshoot with. Anyway, since it is isolated to a single channel I would be crawling through the vertical gain stages.

Ron

 

[Inquisitive]

Here is a view of a normal working Channel 2 in calibration mode

**broken link removed**

Here is the problem channel 1. Anyone have any ideas?

**broken link removed**

**broken link removed**


Thanks for your help.

P.S. The same probe is used on both channels in the instance.

 

[Reloadron]

Attached are 3 images from one of my scopes. On a vertical input channel they represent Over Compensation, Normal Compensation and Under Compensation.

Right behind the vertical input connector there should be some switching for the input attenuator. There should be adjustable caps right in that neighborhood. This is a ***** sans vertical input schematic. The vertical inputs should have some adjustable caps in there. Sometimes each channel will have three that correspond to the 1, 2, 5 input ranging and maybe just one.

It looks to me like there is over compensation for the high frequencies of the leading edge of the test square wave in your images (the second image).

Ron