Pye LV30 restoration project - UK Vintage Radio Repair and Restoration Discussion Forum

yagosaga · 25th Feb 2007, 11:55 pm

Hello,

Last week I got a PYE LV30.

Tonight I have removed the chassis for a first inspection. I never saw such a dirty and sooty chassis.

The set has a MW22-17 picture tube. I tested it with the CRT tester, and it has 0.9 mA which seems to be good. The CRT has a straight electron gun and no ion trap. Or didn't I recognize it?
In the schematics I got from Paul Stenning there is some kind of ion trap at the crt.

Are there several models of LV30's with and without ion trap?

What do I have to consider when restoring the set?

Which capacitors I should replace at first?

Kind regards,
Eckhard

Steve_P · 26th Feb 2007, 12:06 am

Well, try replacing anything on the HT line or round the line + frame stages. Also anything else that looks crispy. Then use your variac to bring it up gently.

The manual I have makes no reference to ion trap magnets.

Cheers,

Steve P

Denis G4DWC · 26th Feb 2007, 1:10 am

The MW22-17 doesnt need an Ion Trap. However, when it became obsolete it was replaced by the MW22-16 which did need one. HTH
Denis

Mike Phelan · 26th Feb 2007, 8:51 am

If a CRT needs an ion trap, you will see that the gun assembly looks slightly "bent" at about 5 degrees (so the ions hit the neck, but the magnet pulls the electron beam back on track).

yagosaga · 27th Feb 2007, 6:36 pm

Thank you very much for your replies. Yesterday I have cleaned the chassis. The electrolytic capacitors had become unformatted. I have formatted them. The next step will be checking the capacitors of the horizontal and vertical unit.

Regards,
Eckhard

yagosaga · 27th Feb 2007, 11:29 pm

Hello,

After replacing C33, C34, C60, C62, and C63 I switched the set on. The valves light up. Line output and frame output are operating, but no high voltage.
At the plate of the EY51 there was high voltage. I tested it with a wire, grounded over 200K.
The EY51 seems to be bad. Tomorrow I will replace it with a spare valve.

Regards,
Eckhard

yagosaga · 1st Mar 2007, 12:14 am

Hello,

tonight I have replaced the EY51. After that I got a raster with a signal, but without synchronisation. I replaced C29 and C58 and then I got full synchronisation. As you can see, the picture tube has an ion burn. But this is OK, it is old-fashioned television watching.

Kind regards,
Eckhard

Colin · 1st Mar 2007, 2:38 pm

I think the phrase 'less is more' applies here ... the engineers produced 'elegant' rather than 'simple' solutions. Cost effective is in there somewhere but it's much more than that.

Well done Eckhard the finished set looks great. Perfect for watching 'Dinner for One' on New Years Eve!

Colin

yagosaga · 8th Mar 2007, 6:03 pm

Hello,

when I watched TV with the LV30, picture became bright after half an hour and sound died away. A check revealed a d.c. component of 8 V at the grid of the video output tube without signal which is too high. Darius assumed an oscillating amplifying stage and suggested to short out the filaments of each valve successive to find out which amplifying valve is oscillating.

It was V2. He gave me the tip to replace these small brown capacitors of 1 nF value. They are C5, C6, C7, C8, C9, and C10. After replacing them, picture and sound were OK again.

Kind regards,
Eckhard

25th Feb 2007, 11:55 pm	#1
yagosaga Retired Dormant Member Join Date: Mar 2005 Location: Braunschweig, Germany Posts: 208	Pye LV30 restoration project Hello, Last week I got a PYE LV30. Tonight I have removed the chassis for a first inspection. I never saw such a dirty and sooty chassis. The set has a MW22-17 picture tube. I tested it with the CRT tester, and it has 0.9 mA which seems to be good. The CRT has a straight electron gun and no ion trap. Or didn't I recognize it? In the schematics I got from Paul Stenning there is some kind of ion trap at the crt. Are there several models of LV30's with and without ion trap? What do I have to consider when restoring the set? Which capacitors I should replace at first? Kind regards, Eckhard

26th Feb 2007, 12:06 am	#2
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: PYE LV30 restoration project Well, try replacing anything on the HT line or round the line + frame stages. Also anything else that looks crispy. Then use your variac to bring it up gently. The manual I have makes no reference to ion trap magnets. Cheers, Steve P __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

26th Feb 2007, 1:10 am	#3
Denis G4DWC Pentode Join Date: Oct 2006 Location: Brackley Northamptonshire, UK. Posts: 240	Re: PYE LV30 restoration project The MW22-17 doesnt need an Ion Trap. However, when it became obsolete it was replaced by the MW22-16 which did need one. HTH Denis __________________ If you take something apart often enough, eventually you'll have two of them....

26th Feb 2007, 8:51 am	#4
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: PYE LV30 restoration project If a CRT needs an ion trap, you will see that the gun assembly looks slightly "bent" at about 5 degrees (so the ions hit the neck, but the magnet pulls the electron beam back on track). __________________ Mike.

27th Feb 2007, 6:36 pm	#5
yagosaga Retired Dormant Member Join Date: Mar 2005 Location: Braunschweig, Germany Posts: 208	Re: PYE LV30 restoration project Thank you very much for your replies. Yesterday I have cleaned the chassis. The electrolytic capacitors had become unformatted. I have formatted them. The next step will be checking the capacitors of the horizontal and vertical unit. Regards, Eckhard

27th Feb 2007, 11:29 pm	#6
yagosaga Retired Dormant Member Join Date: Mar 2005 Location: Braunschweig, Germany Posts: 208	Re: PYE LV30 restoration project Hello, After replacing C33, C34, C60, C62, and C63 I switched the set on. The valves light up. Line output and frame output are operating, but no high voltage. At the plate of the EY51 there was high voltage. I tested it with a wire, grounded over 200K. The EY51 seems to be bad. Tomorrow I will replace it with a spare valve. Regards, Eckhard

1st Mar 2007, 12:14 am	#7
yagosaga Retired Dormant Member Join Date: Mar 2005 Location: Braunschweig, Germany Posts: 208	Re: PYE LV30 restoration project Hello, tonight I have replaced the EY51. After that I got a raster with a signal, but without synchronisation. I replaced C29 and C58 and then I got full synchronisation. As you can see, the picture tube has an ion burn. But this is OK, it is old-fashioned television watching. Kind regards, Eckhard Attached Thumbnails

1st Mar 2007, 2:38 pm	#8
Colin Heptode Join Date: Jun 2004 Location: Ilkley, West Yorkshire, UK. Posts: 656	Re: PYE LV30 restoration project I think the phrase 'less is more' applies here ... the engineers produced 'elegant' rather than 'simple' solutions. Cost effective is in there somewhere but it's much more than that. Well done Eckhard the finished set looks great. Perfect for watching 'Dinner for One' on New Years Eve! Colin

8th Mar 2007, 6:03 pm	#9
yagosaga Retired Dormant Member Join Date: Mar 2005 Location: Braunschweig, Germany Posts: 208	Re: PYE LV30 restoration project Hello, when I watched TV with the LV30, picture became bright after half an hour and sound died away. A check revealed a d.c. component of 8 V at the grid of the video output tube without signal which is too high. Darius assumed an oscillating amplifying stage and suggested to short out the filaments of each valve successive to find out which amplifying valve is oscillating. It was V2. He gave me the tip to replace these small brown capacitors of 1 nF value. They are C5, C6, C7, C8, C9, and C10. After replacing them, picture and sound were OK again. Kind regards, Eckhard