Saved from the Biffa Bin: Bush TV22. - UK Vintage Radio Repair and Restoration Discussion Forum

FERNSEH · 2nd May 2014, 11:14 am

I've been asked to repair this Bush TV22. A quick glance reveals that it is a really tidy unmolested set. I'm sure this one is going to be an easy fix. Let's find out.

DFWB.

Peter.N. · 2nd May 2014, 11:48 am

Nice find.

FERNSEH · 2nd May 2014, 11:59 am

Standard HKS test procedure, just plug it in and we've got results already. A thin white line across the screen. The volume control crackles when turned so we know that the sound output stage works. The CRT A1 volts are low, only 78 volts. Likely to be leaky waxies.

Standby for more news on how the resto job goes.

#DFWB.

FERNSEH · 2nd May 2014, 12:13 pm

I think you'll agree this 1mfd filter capacitor needs replacing. It's just about ready to go bang!

DFWB.

mark pirate · 2nd May 2014, 12:47 pm

I had the same problem with mine, turned out to be the blocking transformer O/C.

Mark

FERNSEH · 2nd May 2014, 1:58 pm

C18 the boost HT smoothing capacitor was found to be leaky, as you would expect so replacing it has resulted in a bright white line across the screen.
The capacitor is located under the component group board which is under the main chassis.

DFWB.

Focus Diode · 2nd May 2014, 3:33 pm

I had great pleasure in seeing David and the set earlier today. I've never been inside a TV22 before so a new experience for me. The condition of the set is amazing with no evidence of any repair work, although we did notice the frame output valve being a 1960s replacement. The internal wiring is sound although one or two of the wax capacitors look as if they've been chewed at some point. Not sure if there's such a thing as a "Wax Beetle", whatever it was at least it left the wiring alone!

I was as confident as David was just to plug it in following the usual cold checks. The first image shows the very first light, before the HT smoothing capacitor was replaced. This soon faded out as the leak increased. Replacement components show the CRT to be in excellent condition, it'll only be a moment of time before full scan is obtained.

Cheers,
Brian

FERNSEH · 2nd May 2014, 3:41 pm

Hi Brian,
After doing so well so far with the service work on the set I find that the frame blocking transformer has an open circuit primary. I have a Plessey made component to hand, however, as it is much larger than the original it will have to be mounted on the other side of the right side chassis member. The original transformer is a small component and is fitted on the right side component group board.
The replacement frame output valve is a Tungsram ECL80 and is date coded B7B3. July 1967, I doubt if it is 1977. Tungsram valves were once assigned American type numbers, for example the ECL80 is the 6AB8. Anyway, it would seem that the set was still in use well into the 1960s. Says a lot about the reliability of these sets.

DFWB.

Focus Diode · 2nd May 2014, 5:32 pm

One wonders if the blocking osc transformer failiure resulted in its retirement in 1967? There's that snipped capacitor between the height control and chassis worth noting too. Perhaps after valve replacement and cutting the capacitor lead to the height control the engineer discovered the defective transformer. Either a replacement couldn't readily be obtained or the set considered uneconomic to repair seeing it was already 15 years old?

Hopefully, mounting the replacement won't be too difficult. Perhaps an adaptor plate will be needed?!

Cheers,
Brian

mark pirate · 2nd May 2014, 6:09 pm

As I said in post #5, the blocking tx going O/C seems to be a problem with these sets.
I 'borrowed' the one from my TV24 to finish off the restoration of my TV22, I do intend to restore the TV24 later this year, so another will have to be found.
Apparently these are not that critical, so I will try a couple I have from a Cossor & a GEC sets that I scrapped several years ago.
I will be very interested to see if your 'transplant' works ok.

Mark

Heatercathodeshort · 2nd May 2014, 8:07 pm

I knew I should have put a sledge hammer through that TV22 when I discovered it lurking in yer bin...
I want to see a picture by tomorrow night or I will personally arrive at your workshop and deal with it...John.

FERNSEH · 2nd May 2014, 8:30 pm

Hi John,
I better return to the workshop and work through the wee small hours and get it working.

DFWB.

FERNSEH · 2nd May 2014, 11:33 pm

The replacement blocking oscillator transformer has been fitted. After a bit fiddling with the controls the vertical timebase is working in a manner.
It's likely that the frame hold control is OC at one end and the height and linearity controls need some attention. It's also most likely all the waxies in the timebase will in due course need replacing. There are four TCC 0.1mfd capacitors in this timebase circuit.

Nevertheless we're getting positive results from this set.

DFWB.

Dave Moll · 3rd May 2014, 10:47 am

Hopefully, you've done enough to save it from John's sledgehammer!

FERNSEH · 3rd May 2014, 10:54 am

Last nights work was not a waste of time, I've gotta picture of sorts. John will not heading North when he sees these results.

DFWB.

Focus Diode · 3rd May 2014, 11:18 am

That's excellent progress, less than 24 hours since the first switch on. A great achievement.

Cheers,
Brian

Radio Wrangler · 3rd May 2014, 12:04 pm

I can't imagine John putting a sledge hammer through an interesting classic telly. I thought he cruised the country at night depositing old sets with carefully induced faults in dustbins and skips far and wide. Then he watches them turn up on here and sees how log it takes the targetted people to fix them.

Shades of Flanders & Swan "Bedstead Men"

David

Tazman1966 · 3rd May 2014, 5:57 pm

Like the picture of the scary sweaty mains filter cap

! Great results so far and John, KEEP AWAY!

Stubble · 3rd May 2014, 8:30 pm

Excellent, another one of these great little sets saved and preserved in working order.

I just love bush TV sets and working on them.

Lee

Heatercathodeshort · 4th May 2014, 9:17 am

Remember David, I'm qualified to drive skip lorries so you had better hide that TV22 before the air is filled with the sound of crunching Bakelite..
The camera just caught the last moments of this duckie little thing before the mad woodmans's hammer found it's target.. They make your brain soft yer know.

Any FBOT will work in the TV22 but it needs to be a high impedance ratio.
Most transformers have around 200 ohm windings or less and will give lack of height, one ended frame hold control and poor linearity. They will make a very good test replacement until the original can be rewound. From memory I think around 500ohms for the original is the norm. John.

2nd May 2014, 11:14 am	#1
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Saved from the Biffa Bin: Bush TV22. I've been asked to repair this Bush TV22. A quick glance reveals that it is a really tidy unmolested set. I'm sure this one is going to be an easy fix. Let's find out. DFWB. Attached Thumbnails

2nd May 2014, 11:48 am	#2
Peter.N. Dekatron Join Date: Jul 2008 Location: Charmouth, Dorset, UK. Posts: 3,601	Re: Saved from the Biffa Bin: Bush TV22. Nice find.

2nd May 2014, 11:59 am	#3
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Saved from the Biffa Bin: Bush TV22. Standard HKS test procedure, just plug it in and we've got results already. A thin white line across the screen. The volume control crackles when turned so we know that the sound output stage works. The CRT A1 volts are low, only 78 volts. Likely to be leaky waxies. Standby for more news on how the resto job goes. #DFWB.

2nd May 2014, 12:13 pm	#4
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Saved from the Biffa Bin: Bush TV22. I think you'll agree this 1mfd filter capacitor needs replacing. It's just about ready to go bang! DFWB. Attached Thumbnails

2nd May 2014, 1:58 pm	#6
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Saved from the Biffa Bin: Bush TV22. C18 the boost HT smoothing capacitor was found to be leaky, as you would expect so replacing it has resulted in a bright white line across the screen. The capacitor is located under the component group board which is under the main chassis. DFWB.

2nd May 2014, 12:47 pm	#5
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Saved from the Biffa Bin: Bush TV22. I had the same problem with mine, turned out to be the blocking transformer O/C. Mark

2nd May 2014, 3:33 pm	#7
Focus Diode Octode Join Date: Jan 2006 Location: Borough of Gateshead, UK. Posts: 1,420	Re: Saved from the Biffa Bin: Bush TV22. I had great pleasure in seeing David and the set earlier today. I've never been inside a TV22 before so a new experience for me. The condition of the set is amazing with no evidence of any repair work, although we did notice the frame output valve being a 1960s replacement. The internal wiring is sound although one or two of the wax capacitors look as if they've been chewed at some point. Not sure if there's such a thing as a "Wax Beetle", whatever it was at least it left the wiring alone! I was as confident as David was just to plug it in following the usual cold checks. The first image shows the very first light, before the HT smoothing capacitor was replaced. This soon faded out as the leak increased. Replacement components show the CRT to be in excellent condition, it'll only be a moment of time before full scan is obtained. Cheers, Brian Attached Thumbnails

2nd May 2014, 3:41 pm	#8
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Saved from the Biffa Bin: Bush TV22. Hi Brian, After doing so well so far with the service work on the set I find that the frame blocking transformer has an open circuit primary. I have a Plessey made component to hand, however, as it is much larger than the original it will have to be mounted on the other side of the right side chassis member. The original transformer is a small component and is fitted on the right side component group board. The replacement frame output valve is a Tungsram ECL80 and is date coded B7B3. July 1967, I doubt if it is 1977. Tungsram valves were once assigned American type numbers, for example the ECL80 is the 6AB8. Anyway, it would seem that the set was still in use well into the 1960s. Says a lot about the reliability of these sets. DFWB. Last edited by FERNSEH; 2nd May 2014 at 3:48 pm.

2nd May 2014, 5:32 pm	#9
Focus Diode Octode Join Date: Jan 2006 Location: Borough of Gateshead, UK. Posts: 1,420	Re: Saved from the Biffa Bin: Bush TV22. One wonders if the blocking osc transformer failiure resulted in its retirement in 1967? There's that snipped capacitor between the height control and chassis worth noting too. Perhaps after valve replacement and cutting the capacitor lead to the height control the engineer discovered the defective transformer. Either a replacement couldn't readily be obtained or the set considered uneconomic to repair seeing it was already 15 years old? Hopefully, mounting the replacement won't be too difficult. Perhaps an adaptor plate will be needed?! Cheers, Brian

2nd May 2014, 6:09 pm	#10
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Saved from the Biffa Bin: Bush TV22. As I said in post #5, the blocking tx going O/C seems to be a problem with these sets. I 'borrowed' the one from my TV24 to finish off the restoration of my TV22, I do intend to restore the TV24 later this year, so another will have to be found. Apparently these are not that critical, so I will try a couple I have from a Cossor & a GEC sets that I scrapped several years ago. I will be very interested to see if your 'transplant' works ok. Mark

2nd May 2014, 8:07 pm	#11
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Saved from the Biffa Bin: Bush TV22. I knew I should have put a sledge hammer through that TV22 when I discovered it lurking in yer bin... I want to see a picture by tomorrow night or I will personally arrive at your workshop and deal with it...John.

2nd May 2014, 8:30 pm	#12
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Saved from the Biffa Bin: Bush TV22. Hi John, I better return to the workshop and work through the wee small hours and get it working. DFWB.

2nd May 2014, 11:33 pm	#13
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Saved from the Biffa Bin: Bush TV22. The replacement blocking oscillator transformer has been fitted. After a bit fiddling with the controls the vertical timebase is working in a manner. It's likely that the frame hold control is OC at one end and the height and linearity controls need some attention. It's also most likely all the waxies in the timebase will in due course need replacing. There are four TCC 0.1mfd capacitors in this timebase circuit. Nevertheless we're getting positive results from this set. DFWB. Attached Thumbnails

3rd May 2014, 10:47 am	#14
Dave Moll Dekatron Join Date: Feb 2005 Location: West Cumbria (CA13), UK Posts: 6,130	Re: Saved from the Biffa Bin: Bush TV22. Hopefully, you've done enough to save it from John's sledgehammer! __________________ Mending is better than Ending (cf Brave New World by Aldous Huxley)

3rd May 2014, 10:54 am	#15
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Saved from the Biffa Bin: Bush TV22. Last nights work was not a waste of time, I've gotta picture of sorts. John will not heading North when he sees these results. DFWB. Attached Thumbnails

3rd May 2014, 11:18 am	#16
Focus Diode Octode Join Date: Jan 2006 Location: Borough of Gateshead, UK. Posts: 1,420	Re: Saved from the Biffa Bin: Bush TV22. That's excellent progress, less than 24 hours since the first switch on. A great achievement. Cheers, Brian

3rd May 2014, 12:04 pm	#17
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,902	Re: Saved from the Biffa Bin: Bush TV22. I can't imagine John putting a sledge hammer through an interesting classic telly. I thought he cruised the country at night depositing old sets with carefully induced faults in dustbins and skips far and wide. Then he watches them turn up on here and sees how log it takes the targetted people to fix them. Shades of Flanders & Swan "Bedstead Men" David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

3rd May 2014, 5:57 pm	#18
Tazman1966 Nonode Join Date: May 2006 Location: St Albans, Herts, UK. Posts: 2,193	Re: Saved from the Biffa Bin: Bush TV22. Like the picture of the scary sweaty mains filter cap! Great results so far and John, KEEP AWAY! __________________ All the very best, Tas

3rd May 2014, 8:30 pm	#19
Stubble Pentode Join Date: Nov 2011 Location: Powys, Wales, UK. Posts: 189	Re: Saved from the Biffa Bin: Bush TV22. Excellent, another one of these great little sets saved and preserved in working order. I just love bush TV sets and working on them. Lee

4th May 2014, 9:17 am	#20
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Saved from the Biffa Bin: Bush TV22. Remember David, I'm qualified to drive skip lorries so you had better hide that TV22 before the air is filled with the sound of crunching Bakelite.. The camera just caught the last moments of this duckie little thing before the mad woodmans's hammer found it's target.. They make your brain soft yer know. Any FBOT will work in the TV22 but it needs to be a high impedance ratio. Most transformers have around 200 ohm windings or less and will give lack of height, one ended frame hold control and poor linearity. They will make a very good test replacement until the original can be rewound. From memory I think around 500ohms for the original is the norm. John. Attached Thumbnails