BK Precision 1535A Oscilloscope

[Axtman]

Yesterday I picked up this scope for a cheap price. It works but needs calibrating. I found the schematic and parts list, but does anyone have or know a resource for the owner's manual?

BK Precision make a kajillion types of scopes over the years. Sometimes I wonder if they had a Scope of the Month club since they release so many! If worse comese to worse I might be able to find a model that is close and use that calibration procedure.

[dmeek]

Here is the manual. I don't have the schematic, please post it or a link to it if you can.

BK 1535a_2x5mv_35mhz_delayed_oscilloscope_sm no sch.pdf

edit: I just noticed this manual refers to the 1474. Don't know if they're the same

[Axtman]

dmeek,

I cannot open your file but I am sure it is the same one I downloaded. BK Precision 1535A and 1474 are not the same models.

Attached is the parts list / schematic for 1535A.

[tedmich]

I think BK will send you any manual requested here: https://www.bkprecision.com/index.ph...=22&Itemid=147

[mozz]

Why do you need it calibrated? If it doesn't have the digital readout you are counting blocks. Scopes that old are not known to be as accurate as a true rms meter, freq counter, volt meter. Use it for looking at waveforms, clipping, oscillations.

[Axtman]

I want it calibrate (or maybe a better term is "adjusted") ecause the current waveform is ugly. The square wave is thick on the horizontal and thin on the vertical. I know it is not a laboratory grade instrument but I would like to adjust it to be as accurate as possible.

[mozz]

That could be a hi volt problem. There might be a sharpness control? Also might be a cal control for setting up the probe for a nice square wave.

[Axtman]

Mozz, I will check those out, but regardless I still want a copy of the manual.

[Axtman]

I found it! Due to my Super Dog Sleuthing abilities I located the manual!

I remembered BK Precision is also Trio-Kenwood Corporation or vice-versa. So I went about looking for Trio oscilloscope manuals. I found the service manual for CS-1560A on Boat Anchor Manual Archive (https://bama.edebris.com) and it appears to be the exact model of my oscilloscope (rebranded of course).