Leader LBO 522 - UK Vintage Radio Repair and Restoration Discussion Forum

sparkymike · 7th Feb 2020, 5:54 pm

I have a Leader LBO 522 scope I am checking out and the time/div rotary control is nearly seized. Is this just a matter of lubrication in the vital points?
Mike.

sparkymike · 7th Feb 2020, 7:20 pm

Ok on the rotary control now, it just needed a touch of penetrating oil on the shaft. I then found that the hold rotary control had same problem, but now that is fine. Now problem I now have is that the trace is very wide, and the intensity control makes no difference at all. I do have the circuit, but may well need some help here. Focus control also makes no chance when turned.
Mike.

sparkymike · 8th Feb 2020, 12:26 pm

Well I thought I would check the main board for faulty components, but did not get far before I saw the crack in the board, so the board is now out and is in the process of being repaired. About five tracks to link and one component which is smashed, which I think is a neon. There are three of these marked V1/V2 and V3 and the crack runs through them. Any advise on substitution /type/voltage,would be welcome.
Mike.

WME_bill · 9th Feb 2020, 12:15 am

Leader LBO522.
Your three neons, v1/v2/v3 are very uncritical. They help prevent the grid voltage going too far away from the cathode of the CRT, and partly stabilise the brightness for variations in control settings.
Type NE38B on the circuit. Probably about 60V at 200ua. Any small indicator neons you can find, but without the series resistor fitted if a panel lamp. Most are around 55V to 80V.
wme_bill

sparkymike · 9th Feb 2020, 9:00 am

Thanks for info Bill. I bridged around five breaks in the board, replaced it and still did not work, but on looking very closely at the board I found two more breaks.
I removed a neon from an indicator lamp and now it all works a treat.
It looks to be very well made scope, being Japanese, their attention to detail is mostly always top notch.
Mike.

Herald1360 · 11th Feb 2020, 11:33 am

We had a couple of Leader 'scopes at work amongst the usual HP and Tek suspects. For what you might call "everyday" use they were my preferred "go to", at least until the Tek THS700 series handhelds came along with their brilliant rolling slow speed storage display mode.

Definitely a "Ronseal" bit of kit.

7th Feb 2020, 5:54 pm	#1
sparkymike Octode Join Date: Dec 2006 Location: Colchester, Essex, UK. Posts: 1,076	Leader LBO 522 I have a Leader LBO 522 scope I am checking out and the time/div rotary control is nearly seized. Is this just a matter of lubrication in the vital points? Mike.

7th Feb 2020, 7:20 pm	#2
sparkymike Octode Join Date: Dec 2006 Location: Colchester, Essex, UK. Posts: 1,076	Re: Leader LBO 522 Ok on the rotary control now, it just needed a touch of penetrating oil on the shaft. I then found that the hold rotary control had same problem, but now that is fine. Now problem I now have is that the trace is very wide, and the intensity control makes no difference at all. I do have the circuit, but may well need some help here. Focus control also makes no chance when turned. Mike.

8th Feb 2020, 12:26 pm	#3
sparkymike Octode Join Date: Dec 2006 Location: Colchester, Essex, UK. Posts: 1,076	Re: Leader LBO 522 Well I thought I would check the main board for faulty components, but did not get far before I saw the crack in the board, so the board is now out and is in the process of being repaired. About five tracks to link and one component which is smashed, which I think is a neon. There are three of these marked V1/V2 and V3 and the crack runs through them. Any advise on substitution /type/voltage,would be welcome. Mike. Attached Thumbnails

9th Feb 2020, 12:15 am	#4
WME_bill Octode Join Date: Oct 2007 Location: Exeter, Devon, UK. Posts: 1,554	Re: Leader LBO 522 Leader LBO522. Your three neons, v1/v2/v3 are very uncritical. They help prevent the grid voltage going too far away from the cathode of the CRT, and partly stabilise the brightness for variations in control settings. Type NE38B on the circuit. Probably about 60V at 200ua. Any small indicator neons you can find, but without the series resistor fitted if a panel lamp. Most are around 55V to 80V. wme_bill

9th Feb 2020, 9:00 am	#5
sparkymike Octode Join Date: Dec 2006 Location: Colchester, Essex, UK. Posts: 1,076	Re: Leader LBO 522 Thanks for info Bill. I bridged around five breaks in the board, replaced it and still did not work, but on looking very closely at the board I found two more breaks. I removed a neon from an indicator lamp and now it all works a treat. It looks to be very well made scope, being Japanese, their attention to detail is mostly always top notch. Mike.

11th Feb 2020, 11:33 am	#6
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Leader LBO 522 We had a couple of Leader 'scopes at work amongst the usual HP and Tek suspects. For what you might call "everyday" use they were my preferred "go to", at least until the Tek THS700 series handhelds came along with their brilliant rolling slow speed storage display mode. Definitely a "Ronseal" bit of kit. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O Last edited by Herald1360; 11th Feb 2020 at 11:38 am.