Hello all!
I've decided to crawl out of my cave and finally register here on the forum!
It only seems right for my first post to be about my second oscilloscope purchase, which I found on craigslist some months ago for only $10!!!
This Leader LBO-513A had been sitting in a gentleman's basement for some years. He said he powered it up and was unable to get a trace to show up so I figured it'd be worth a shot at trying to repair, or would make a pretty night stand.
He had bought it from a neighbor's yard sale many years ago and it came as is, with no probes. I cringed when he told me he used to shove wires into the BNC when using it
I found a zip file with about 30 bitmap images of scans of the original manual, which I cleaned up and made a pdf with:
http://frankfort-electronics.com/soapland/manuals/Leader_LBO-513/Leader%20LBO-513.pdfImagine my surprise when I got it home, hooked a probe up from my HP 54502a, and with a bit of knob/button play... the .5VP-P test signal appeared!!! A working 15mhz 'scope for only $10!!
I later calibrated it (according to the manual) and it's worked rather well since.. I did notice a few of the pots on the boards are not mentioned in the manual. One curious tick is that at certain levels when triggering on a 1khz sine wave, an inverted waveform will appear along with the expected waveform, so that seems a bit dicky. Also the focus/intensity controls dont seem to clean up the trace as well when measuring <100mVP-P, but I realize this is from what I can tell a low end vintage 'scope.. so for $10 I can't complain too much. If anyone has any suggestions or ideas about tweaking the pots that aren't mentioned in the manual, please feel free to enlighten me as I am not a seasoned pro with EE or test equip.
I found one IC in it (on the vertical board), a MPQ918 (Quad memory driver transistor) - date code 45th week of 1984
All considered, it seems to work rather well and was a great deal.. perfect for a bit of portability as my HP 54502a, although much higher bandwidth, is much heaver, more fragile and more valuable.
Hope ya'll enjoy the pictures, sorry they aren't breath taking. Let me know if anyone is interested in a video, or more pictures.
Cheers!