Leader 8022 20MHz 2-Channel Oscilloscope service data wanted - UK Vintage Radio Repair and Restoration Discussion Forum

Colin · 16th Oct 2007, 12:05 pm

I'm having trouble with the timebase lock on my Leader 8022 scope and really could do with a circuit diagram/service manual.

Does anyone have a copy they can let me have or know of a source of this information on the web?

Thanks
Colin

Ed_Dinning · 16th Oct 2007, 7:58 pm

Hi Colin, failing getting a circuit you could try looking at the PCB as the functions were often silk screened onto it. Look for the usual leaky caps and also high value resistors.
Clean sync selector switches and also clean ther board.
If all else fails I have a coulpe of nice scopes to tempt you next time you are in the area.

Best regards, Ed

Colin · 16th Oct 2007, 9:49 pm

Hi Ed, thanks for the tips. I'll have a poke around. You're right, there's a lot of info silk screened on the board and it is possible to roughly locate the triggering circuit components. I'll cover off the basics - caps and high value resistors and also give the switch a shot of servisol. The trace can be stabilised by using the Holdoff control but it drifts. Also the sweep seems to be very unstable and has a slight 'waving' motion when there's no input.

It's annoying as this one is my 'Sunday Best' scope ... perhaps I will take you up on your invitation when next I'm in the North!

rgds
Colin

Colin · 17th Oct 2007, 11:10 am

Result

I emailed those nice people at Leader Instruments in the US and they've sent me the LS 8022 Service Manual in PDF format - FOC.

What great customer service.

Now all I have to do is fix the scope ...

rgds
Colin

Ed_Dinning · 17th Oct 2007, 9:30 pm

Hi Colin, if otherthings are drifting as well try checking the main HT rails as if they are drifting other things are often referenced to them and drift as well.

Ed

Colin · 17th Oct 2007, 9:47 pm

Hi Ed,

The main HT rail is spot on at 185v and as the CRT EHT is 2KV I haven't tried to measure it yet!

Colin

16th Oct 2007, 12:05 pm	#1
Colin Heptode Join Date: Jun 2004 Location: Ilkley, West Yorkshire, UK. Posts: 656	Leader 8022 20MHz 2-Channel Oscilloscope service data wanted I'm having trouble with the timebase lock on my Leader 8022 scope and really could do with a circuit diagram/service manual. Does anyone have a copy they can let me have or know of a source of this information on the web? Thanks Colin __________________ Colin Armstrong

16th Oct 2007, 7:58 pm	#2
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,195	Re: Leader 8022 20MHz 2-Channel Oscilloscope service data wanted Hi Colin, failing getting a circuit you could try looking at the PCB as the functions were often silk screened onto it. Look for the usual leaky caps and also high value resistors. Clean sync selector switches and also clean ther board. If all else fails I have a coulpe of nice scopes to tempt you next time you are in the area. Best regards, Ed

16th Oct 2007, 9:49 pm	#3
Colin Heptode Join Date: Jun 2004 Location: Ilkley, West Yorkshire, UK. Posts: 656	Re: Leader 8022 20MHz 2-Channel Oscilloscope service data wanted Hi Ed, thanks for the tips. I'll have a poke around. You're right, there's a lot of info silk screened on the board and it is possible to roughly locate the triggering circuit components. I'll cover off the basics - caps and high value resistors and also give the switch a shot of servisol. The trace can be stabilised by using the Holdoff control but it drifts. Also the sweep seems to be very unstable and has a slight 'waving' motion when there's no input. It's annoying as this one is my 'Sunday Best' scope ... perhaps I will take you up on your invitation when next I'm in the North! rgds Colin __________________ Colin Armstrong

17th Oct 2007, 11:10 am	#4
Colin Heptode Join Date: Jun 2004 Location: Ilkley, West Yorkshire, UK. Posts: 656	Re: Leader 8022 20MHz 2-Channel Oscilloscope service data wanted Result I emailed those nice people at Leader Instruments in the US and they've sent me the LS 8022 Service Manual in PDF format - FOC. What great customer service. Now all I have to do is fix the scope ... rgds Colin __________________ Colin Armstrong

17th Oct 2007, 9:30 pm	#5
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,195	Re: Leader 8022 20MHz 2-Channel Oscilloscope service data wanted Hi Colin, if otherthings are drifting as well try checking the main HT rails as if they are drifting other things are often referenced to them and drift as well. Ed

17th Oct 2007, 9:47 pm	#6
Colin Heptode Join Date: Jun 2004 Location: Ilkley, West Yorkshire, UK. Posts: 656	Re: Leader 8022 20MHz 2-Channel Oscilloscope service data wanted Hi Ed, The main HT rail is spot on at 185v and as the CRT EHT is 2KV I haven't tried to measure it yet! Colin __________________ Colin Armstrong