![\"img_7070\"](\"https:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2016\/11\/img_7070.jpg\")
<\/a><\/p>\nAfter that, I put a sine in the X & Y, and fiddled with the bias controls until I got maximum linearity.\u00a0 The sweep & trigger is a little wonky, so I think I’ll run some tests with an external sweep generator to dial the amp sections in first, before I tackle the sweep.\u00a0 Besides, Benton (who’s scope this is) mostly only uses X\/Y mode, so that’s more important.<\/p>\n
There is some burn-in visible on the CRT, I may poke around eBay to see if there’s a replacement that’s available and inexpensive.\u00a0 The filter caps in the power supply are shockingly good, but I may replace them anyway, at least the paper ones.<\/p>\n
After a congratulatory sip of Bourbon (4 Roses, one of my faves), I realized that all the troubles in this scope stemmed from bad 39k\u03a9 resistors. I wonder if there was a bad batch, or they were all just under spec’d?\u00a0 In any event, I’m going to replace them all, and probably up the rating to 2W, just to be sure.\u00a0 I may also replace the 68k resistors that have drifted as well.<\/p>\n
Here it is triggering on a 100kHz square wave, not bad!<\/p>\n
<\/p>\n","protected":false},"excerpt":{"rendered":" Finally got a trace!\u00a0 Turns out that the open cathode resistor I replaced that I thought was supposed to be a 2.7k was actually supposed to be a 39k, so after rectifying that (with a 33k), and replacing the incorrect … Continue reading <\/a><\/p>\n