- 2026
- Jan
- 17
A Leader LBO-310A Oscilloscope - Part 1: Observations
A friend picked this cute little scope up for me cheap because I’ve been looking for a small, actual CRT scope.
The Leader LBO-310A is a simple 4MHz scope that dates to about 1976. It doesn’t offer much except scope. Let’s take a look.
The device itself is pretty clean, both inside and out. The outer shell still has the plastic covering on the metal, so essentially underneath of this cover it’s brand new. Inside, there’s a little bit of the white corrosion that you get with this vintage of Japanese equipment, but nothing major. This scope was used, but not abused.
Even the cord is still good on this thing. This is one of the few devices that’s come across my bench that doesn’t need a new power cord.
Inside is pretty sparse. This guy is transistorized, so no vacuum fire bottles except for the CRT:
There’s a lot of places for extra components, so this probably was used in other things, or had options that this unit doesn’t have. There is another board behind this one, that’s a power supply board - it’s not really visible unless removed from the unit - there will most likely be some better shots of that later.
So - does it work? It does, that was demonstrated in the ad, but let’s try it out and see if it actually responds. First thing I notice is the pots are gooey and touchy, so it gets some Deoxit…in particular the vertical position pot is very touchy. More on this later.
I’m using a signal generator I picked up at Fort Wayne, a Heathkit IG-72 that I recently did a checkout post on. It needs a little adjustment but will work for this purpose. And yes, the device responds nicely.
The CRT is nice and bright, and the trace sharp. It does need a little rotation, so I’ll pull the manual and see which one of the internal adjustments does that for us.
The vertical position pot does have an issue - right about where it would be set for the trace to be in the middle of the screen, it’s dead. That’s not surprising, that’s probably where it sat most of it’s life, and I believe this unit came from a shop. That’s not a big deal, it looks about like one of those cheap Alpha pots that ratshack used to sell. I’m sure I can pic something up that will work here without issue, and I’ve ordered a couple of devices that should go in here without issue.
Stay tuned for the replacement!
In the meantime, here’s an operator’s manual, service manual, and a catalog page. The operator manual is in barely readable shape, but it’s there. https://wereboar.com … 0A%20Manuals.pdf.zip
Next part of this series: Coming as soon as I get parts.