Dynatron CTV 55 - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

RichClaytonHull · 29th Mar 2013, 1:24 pm

It's been a couple of weeks since I last posted about my TV, as I've been busy with it's best mate the Dynatron Radiogram, not to mention a Teasmade whose clock has died... but regardless I've just had the back of the telly off.

I was surprised by how clean (relatively) it was inside considering it's age.

My question following Malc's message about changing the big red cap with rivets? I've taken some photos of the inside, and was wondering if someone could direct further as to which component I need to replace please. There is a glaring obvious red component on circuit board to the left (viewed from rear) side of the cabinet. Is this it?

Thanks again.

Welsh Anorak · 29th Mar 2013, 2:58 pm

Hi
If you look at the back of the set as in your first picture, on the lower right panel you'll see an orange sticker on the print side. Open the door and lurking behind it is the infamous capacitor. If it's red it needs changing on sight - I'd advise against running the set with the original in place. Replacements were a dull blue, usually - there were a few with a shiny blue outer.
Other things to check are for dry joints on the frame IC's holder (top left panel, centre) and dry joints on the top middle raster correction board's coils. A good look around with a good light will show up any more bad connections.
Looks a nice clean set - as usual, Dynatrons' owners tended to be a bit more economical with their viewing, if not with their money!
Glyn

RichClaytonHull · 29th Mar 2013, 3:26 pm

Cheers Glyn, I opened her up again, with the Wife on standby with a broom handle in case of any accidental electrocution, and I eventually worked out how to open the pivoted door thing (lift and turn)

Big red was very evident when I turned the panel around. Looks a little tricky to desolder insitu as it's bang behind the "door" frame. Looks like the circuit boards slide out somehow? Any advice on that?

Then I'll have to post a message for a replacement part?

Thanks again.

Here's more photos..

bobbyball · 29th Mar 2013, 3:45 pm

Hello, the circuit board is designed to be removed "easily" from the chassis.

All the plugs can be removed (make a note of where they go) and the board is held in the frame by black plastic clips - these can be a bit brittle so go easy with it. After that the whole board is then loose from the set and can be worked on with ease!

Robert

RichClaytonHull · 29th Mar 2013, 4:18 pm

Cheers Robert, I'll give it a go.

Thanks for the input, much appreciated.

Richard

bobbyball · 29th Mar 2013, 4:39 pm

Just go steady.

I have got a replacement capacitor, as have a few others on here, when you are ready...

Robert

stubbyeddy · 29th Mar 2013, 4:53 pm

I have just bought one of these on a bit of a whim! "I was telling Robert only the other day i didnt have room for one!

" havent checked the capacitor yet, mine is the 22" prefixed with the HU on the serial number its a CTV 41 so im watching this thread with great interest!

RichClaytonHull · 29th Mar 2013, 4:56 pm

Thanks Robert... I've just had a tinker, and it came out easy enough.

It did throw some doubt as to which cap I was actually needing to replace. I've added a photo with the likely suspects. Presumably it's "B" (the big red one), but worth checking first.

Thanks in advance.

Richard

RichClaytonHull · 29th Mar 2013, 5:02 pm

Well StubbyEddy, I've just sold (or given away) a perfectly working 1999 Toshiba widescreen TV to make room for this one... spent a long time yesterday polishing the Dynatron cabinet with beeswax, you can almost see your face in it, came up lovely. Just don't want it "exploding" for the sake of an easy repair...

bobbyball · 29th Mar 2013, 5:17 pm

The capacitor in question is indeed the "big red one". It has "Pye" on it.

I'm just trying to think where my "spare" one is. Can't be far as I saw it only the other day. Might be in the "stores" in one of my sheds, will have a look in a bit...

If it were me I would also change the blue one with "ITT" on it and the smaller red one. These are nearer to "standard" values so should be easy to find.

Robert

RichClaytonHull · 29th Mar 2013, 5:33 pm

Thanks again. Well if you find a replacement, I'm happy to arrange some means of payment. I am a total novice when it comes to this DIY TV renovation. On the ITT do I simply find a capacitor with the same or greater micro Farads?. Has printed 47uF 250v DC. Just "googled" it, and plenty of options came up. Ridiculous "school boy" question, but do you need a capacitor that is not only the same spec in terms of uF and voltage, but in also in terms of physical dimensions? i.e. to fit into the existing circuit board?

julie_m · 29th Mar 2013, 6:12 pm

Modern capacitors tend to be smaller than older ones of the same rating, due to improved manufacturing techniques. But as long as the capacitor physically fits into the space available and the leads reach the holes in the board, it will be fine.

You want ideally the same capacitance (µF) or as near as possible, and (unless you know for sure that an over-rated part was used before) the same or greater voltage.

RichClaytonHull · 29th Mar 2013, 6:19 pm

Cheers AJS, good to know, continual learning process. Many thanks.

gec2110 · 29th Mar 2013, 6:34 pm

Hi Nice condition set very good inside and out
Make sure that you change the capacitor i would not use the tv unless it has been changed
and make sure that you get the polarity of the capactor correct
cheers

ntscuser · 29th Mar 2013, 7:57 pm

Should the capacitor be discharged before attempting to remove it?

gec2110 · 30th Mar 2013, 12:10 am

No I never did but make sure that solder any sispect joints and that the HT is set up correctly.

29th Mar 2013, 1:24 pm	#21
RichClaytonHull Retired Dormant Member Join Date: Mar 2013 Location: Hull, East Yorkshire, UK Posts: 29	Re: Dynatron CTV 55 It's been a couple of weeks since I last posted about my TV, as I've been busy with it's best mate the Dynatron Radiogram, not to mention a Teasmade whose clock has died... but regardless I've just had the back of the telly off. I was surprised by how clean (relatively) it was inside considering it's age. My question following Malc's message about changing the big red cap with rivets? I've taken some photos of the inside, and was wondering if someone could direct further as to which component I need to replace please. There is a glaring obvious red component on circuit board to the left (viewed from rear) side of the cabinet. Is this it? Thanks again. Attached Thumbnails

29th Mar 2013, 2:58 pm	#22
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,916	Re: Dynatron CTV 55 Hi If you look at the back of the set as in your first picture, on the lower right panel you'll see an orange sticker on the print side. Open the door and lurking behind it is the infamous capacitor. If it's red it needs changing on sight - I'd advise against running the set with the original in place. Replacements were a dull blue, usually - there were a few with a shiny blue outer. Other things to check are for dry joints on the frame IC's holder (top left panel, centre) and dry joints on the top middle raster correction board's coils. A good look around with a good light will show up any more bad connections. Looks a nice clean set - as usual, Dynatrons' owners tended to be a bit more economical with their viewing, if not with their money! Glyn

29th Mar 2013, 3:26 pm	#23
RichClaytonHull Retired Dormant Member Join Date: Mar 2013 Location: Hull, East Yorkshire, UK Posts: 29	Re: Dynatron CTV 55 Cheers Glyn, I opened her up again, with the Wife on standby with a broom handle in case of any accidental electrocution, and I eventually worked out how to open the pivoted door thing (lift and turn) Big red was very evident when I turned the panel around. Looks a little tricky to desolder insitu as it's bang behind the "door" frame. Looks like the circuit boards slide out somehow? Any advice on that? Then I'll have to post a message for a replacement part? Thanks again. Here's more photos.. Attached Thumbnails

29th Mar 2013, 3:45 pm	#24
bobbyball Octode Join Date: Jul 2011 Location: Stockport, Greater Manchester Posts: 1,214	Re: Dynatron CTV 55 Hello, the circuit board is designed to be removed "easily" from the chassis. All the plugs can be removed (make a note of where they go) and the board is held in the frame by black plastic clips - these can be a bit brittle so go easy with it. After that the whole board is then loose from the set and can be worked on with ease! Robert

29th Mar 2013, 4:18 pm	#25
RichClaytonHull Retired Dormant Member Join Date: Mar 2013 Location: Hull, East Yorkshire, UK Posts: 29	Re: Dynatron CTV 55 Cheers Robert, I'll give it a go. Thanks for the input, much appreciated. Richard

29th Mar 2013, 4:39 pm	#26
bobbyball Octode Join Date: Jul 2011 Location: Stockport, Greater Manchester Posts: 1,214	Re: Dynatron CTV 55 Just go steady. I have got a replacement capacitor, as have a few others on here, when you are ready... Robert

29th Mar 2013, 4:53 pm	#27
stubbyeddy Pentode Join Date: May 2005 Location: Newtown, Mid Wales, UK. Posts: 186	Re: Dynatron CTV 55 I have just bought one of these on a bit of a whim! "I was telling Robert only the other day i didnt have room for one! " havent checked the capacitor yet, mine is the 22" prefixed with the HU on the serial number its a CTV 41 so im watching this thread with great interest!

29th Mar 2013, 4:56 pm	#28
RichClaytonHull Retired Dormant Member Join Date: Mar 2013 Location: Hull, East Yorkshire, UK Posts: 29	Re: Dynatron CTV 55 Thanks Robert... I've just had a tinker, and it came out easy enough. It did throw some doubt as to which cap I was actually needing to replace. I've added a photo with the likely suspects. Presumably it's "B" (the big red one), but worth checking first. Thanks in advance. Richard Attached Thumbnails

29th Mar 2013, 5:02 pm	#29
RichClaytonHull Retired Dormant Member Join Date: Mar 2013 Location: Hull, East Yorkshire, UK Posts: 29	Re: Dynatron CTV 55 Well StubbyEddy, I've just sold (or given away) a perfectly working 1999 Toshiba widescreen TV to make room for this one... spent a long time yesterday polishing the Dynatron cabinet with beeswax, you can almost see your face in it, came up lovely. Just don't want it "exploding" for the sake of an easy repair...

29th Mar 2013, 5:17 pm	#30
bobbyball Octode Join Date: Jul 2011 Location: Stockport, Greater Manchester Posts: 1,214	Re: Dynatron CTV 55 The capacitor in question is indeed the "big red one". It has "Pye" on it. I'm just trying to think where my "spare" one is. Can't be far as I saw it only the other day. Might be in the "stores" in one of my sheds, will have a look in a bit... If it were me I would also change the blue one with "ITT" on it and the smaller red one. These are nearer to "standard" values so should be easy to find. Robert

29th Mar 2013, 5:33 pm	#31
RichClaytonHull Retired Dormant Member Join Date: Mar 2013 Location: Hull, East Yorkshire, UK Posts: 29	Re: Dynatron CTV 55 Thanks again. Well if you find a replacement, I'm happy to arrange some means of payment. I am a total novice when it comes to this DIY TV renovation. On the ITT do I simply find a capacitor with the same or greater micro Farads?. Has printed 47uF 250v DC. Just "googled" it, and plenty of options came up. Ridiculous "school boy" question, but do you need a capacitor that is not only the same spec in terms of uF and voltage, but in also in terms of physical dimensions? i.e. to fit into the existing circuit board?

29th Mar 2013, 6:12 pm	#32
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Dynatron CTV 55 Modern capacitors tend to be smaller than older ones of the same rating, due to improved manufacturing techniques. But as long as the capacitor physically fits into the space available and the leads reach the holes in the board, it will be fine. You want ideally the same capacitance (µF) or as near as possible, and (unless you know for sure that an over-rated part was used before) the same or greater voltage. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

29th Mar 2013, 6:19 pm	#33
RichClaytonHull Retired Dormant Member Join Date: Mar 2013 Location: Hull, East Yorkshire, UK Posts: 29	Re: Dynatron CTV 55 Cheers AJS, good to know, continual learning process. Many thanks.

29th Mar 2013, 6:34 pm	#34
gec2110 Retired Dormant Member Join Date: Feb 2008 Location: Croydon, London, UK. Posts: 408	Re: Dynatron CTV 55 Hi Nice condition set very good inside and out Make sure that you change the capacitor i would not use the tv unless it has been changed and make sure that you get the polarity of the capactor correct cheers

29th Mar 2013, 7:57 pm	#35
ntscuser Hexode Join Date: Mar 2013 Location: Coventry, West Midlands, UK. Posts: 280	Re: Dynatron CTV 55 Should the capacitor be discharged before attempting to remove it?

30th Mar 2013, 12:10 am	#36
gec2110 Retired Dormant Member Join Date: Feb 2008 Location: Croydon, London, UK. Posts: 408	Re: Dynatron CTV 55 No I never did but make sure that solder any sispect joints and that the HT is set up correctly.