25-05-2013, 10:25 PM
(This post was last modified: 25-05-2013, 10:35 PM by AlanBeckett.)
Progress, but not entirely down to my efforts.
A couple of days ago I escaped to the Garage and changed the other three EHT Rectifiers. It was a pig of a job, but I prevailed. One end of C509 came out as I was pushing things about which meant I had to tip the PCB up once again and resolder it. Just in passing all the component leads are very short - barely through the PCB - which makes me nervous.
Anyway, all back together and checked, connect up the Meters and 'scope, take a deap breath and fire up. Wait 90 seconds as usual for the click from the Delay Relay and ............ it was slightly worse than before with the PDA at 6kV and the Oscilator anode swinging less than 400v p-p. Oh, dear, or something similar. Everything seamed OK so I decided that I must have generated another dry joint - see comment above about Component Leads - and the PCB would have to come out and have all its joints properly soldered.
Today Al (skywave) called in and I let him loose on it. Having plied him with coffee I gave him my notes, explained where I'd got to and left him to it as I had to do a bit of taxying. An hour or so later I returned to find he'd discovered a short - bent pin, no doubt generated by me - on the tube base and everything in that area was working splendidly. Even the Controls do pretty well what they're supposed to do. On the Screen there's a nice bright little Lissajous pattern which can be focused etc. I suspect it's hum.
So, now I need the Timebase running I think, and another visit from Al
Alan
A couple of days ago I escaped to the Garage and changed the other three EHT Rectifiers. It was a pig of a job, but I prevailed. One end of C509 came out as I was pushing things about which meant I had to tip the PCB up once again and resolder it. Just in passing all the component leads are very short - barely through the PCB - which makes me nervous.
Anyway, all back together and checked, connect up the Meters and 'scope, take a deap breath and fire up. Wait 90 seconds as usual for the click from the Delay Relay and ............ it was slightly worse than before with the PDA at 6kV and the Oscilator anode swinging less than 400v p-p. Oh, dear, or something similar. Everything seamed OK so I decided that I must have generated another dry joint - see comment above about Component Leads - and the PCB would have to come out and have all its joints properly soldered.
Today Al (skywave) called in and I let him loose on it. Having plied him with coffee I gave him my notes, explained where I'd got to and left him to it as I had to do a bit of taxying. An hour or so later I returned to find he'd discovered a short - bent pin, no doubt generated by me - on the tube base and everything in that area was working splendidly. Even the Controls do pretty well what they're supposed to do. On the Screen there's a nice bright little Lissajous pattern which can be focused etc. I suspect it's hum.
So, now I need the Timebase running I think, and another visit from Al
Alan
