17-05-2015, 10:55 PM
On the face of it the only thing that needed changing was the Mains Connector. However, after I'd had it running for a bit on the Bench I noticed that something was dripping. It turned out to be the Reservoir for the Negative supply. On top it looked pretty sad as well.
The bad news is that it's not connected to the Chassis so a replacement was a bit tricky. The original was 20 + 20 @ 450v. The closest I'd got was 32 + 32 @ 500v which I could just get in by way a bit of butchery to the Insulating Plate. Oddly, the original, despite it's Leak, measured 31 + 37 with respectable ESRs so 32 + 32 is actually pretty close.
Replacing the existing Mains Connector with a standard IEC one was much more straightforward - it just went in with a slight 'Pull' on the Mounting holes. The only added bit was a piece of Wire to connect the Earth Pin to a convenient bit of Chassis, and it works fine.
So, a clean it up, refit the Cover and Robert's your Father's Brother.
Well, not quite. I switched it on again and there was a loud Bang - not good. However, before I could hit the Mains switch it all settled down and everything appeared normal. So I switched off and tried again with the same result - very odd. It turned out to be the perforated Cover. It's Steel, and the surge into the Transformer at switch-on sucks the sides in against the Transformer, hence the bang. I wonder if there was originally a bit of Foam or some such between them although there's nothing in the Manual that I can spot. However, the Manual does charge you not to mount the PSU next to the Display as it will distort the Trace.
I managed one other cock-up while I was at it. I decided I'd make a Test Lead so I didn't have to keep poking into the Octal Sockets. It's simply an old Valve Base wired to a Choc Block. Of course I used the usual Colour Code for the Wires. It wasn't until I was putting in No. 8 that I realised I should have started with Brown not Black so they're all one out. Anybody want to start a Petition to renumber Octal Sockets 0-7 instead of 1 -8
Next the 162 Waveform Generator as that's what drives the Display.
Alan
The bad news is that it's not connected to the Chassis so a replacement was a bit tricky. The original was 20 + 20 @ 450v. The closest I'd got was 32 + 32 @ 500v which I could just get in by way a bit of butchery to the Insulating Plate. Oddly, the original, despite it's Leak, measured 31 + 37 with respectable ESRs so 32 + 32 is actually pretty close.
Replacing the existing Mains Connector with a standard IEC one was much more straightforward - it just went in with a slight 'Pull' on the Mounting holes. The only added bit was a piece of Wire to connect the Earth Pin to a convenient bit of Chassis, and it works fine.
So, a clean it up, refit the Cover and Robert's your Father's Brother.
Well, not quite. I switched it on again and there was a loud Bang - not good. However, before I could hit the Mains switch it all settled down and everything appeared normal. So I switched off and tried again with the same result - very odd. It turned out to be the perforated Cover. It's Steel, and the surge into the Transformer at switch-on sucks the sides in against the Transformer, hence the bang. I wonder if there was originally a bit of Foam or some such between them although there's nothing in the Manual that I can spot. However, the Manual does charge you not to mount the PSU next to the Display as it will distort the Trace.
I managed one other cock-up while I was at it. I decided I'd make a Test Lead so I didn't have to keep poking into the Octal Sockets. It's simply an old Valve Base wired to a Choc Block. Of course I used the usual Colour Code for the Wires. It wasn't until I was putting in No. 8 that I realised I should have started with Brown not Black so they're all one out. Anybody want to start a Petition to renumber Octal Sockets 0-7 instead of 1 -8
Next the 162 Waveform Generator as that's what drives the Display.
Alan
