Re: My first telly TV22
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I've measured most of the resistors and put the results on attached spreadsheet. Im inclined to wait and see when I get power on before changing any - even though some are quite a long way off
Any views ? are any values especially critical on this set? Need to get an order off for new Caps and any resistors I may need |
Re: My first telly TV22
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The advice to dip the LOPT in varnish while still wet was given elsewhere (maybe a post or a PM). |
Re: My first telly TV22
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Re: My first telly TV22
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https://www.vintage-radio.net/forum/...=157811&page=2 So no heat required prior to the varnishing step as water/humidity has already been displaced by the white spirit. |
Re: My first telly TV22
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Just dipping my Lopt in transformer varnish
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Re: My first telly TV22
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Re: My first telly TV22
So should I pull out the primary? I was planning to leave well alone unless I find a problem with them. I was thinking it best not to get varnish inside the core incase the primary windings do need to come out at some point.
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Re: My first telly TV22
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Re: My first telly TV22
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And the idea of preventing failure is also to avoid a rewind, hence keeping the LOPT as original as possible (same interwinding capacitance, same coupling, etc.) |
Re: My first telly TV22
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Caps have arrived , having a go at restuffing some waxies. Ten min in the bottom oven of the AGA melts the wax nicely but don’t tell the missus. Been trying to work out which side of the new capacitors is the outer foil , not sure how critical this is.
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Re: My first telly TV22
To tell which is the outer foil connect to a scope and touch the body of the cap between thumb and finger. The orientation that gives less amplitude on the display mean the lead connected to ground on the scope is the negative.
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Re: My first telly TV22
Thanks, don’t have access to a scope at the moment , I think this will be my next present to myself. Tried connecting to my amplifier and judge hum level but not very satisfactory , I guess depends a lot on the value of the capacitor
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Re: My first telly TV22
Hi Travellingwave,
It is really not critical in the TV22. Generally the outer foil of new capacitors is marked by a thin vertical line at onea end a the label area, but some capacitors are not marked at all. You might be OK jus making sure that the writing is the same way round as on the original capacitor. However, like I said I've never had a problem with capacitor orientation in a TV22. I restored my first TV22 by using polyester X2 caps (dives for cover from the backlash), seriously though they are cheap and reliable replacements for waxies, but being rectangular, they just look wrong. However they never have outer foil markings. Cheers Andy |
Re: My first telly TV22
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I’ve completed first tag board on the main deck. I managed to restuff all the waxies bar two in which the new ones were bigger than the Origionals . One of these was under the tag board so not visible, the other I covered with black sleeve. The audio output valve cathode bypass cap will be replaced with the restuffed origional when I have a more suitable replacement. The big waxy clamped to the chassis was fun. These big chunky tag boards are much easier to work with than the flimsy vertical ones on the couple of Phillips sets I’ve worked on.
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Re: My first telly TV22
Hi Travellingwave,
I take my hat off to you for restuffing the caps in your first TV restoration. My first TV22 which I restored 25 years ago was not as neat as that. However I've since redeemed myself by obtaining another chassis and restuffing the caps in that. People have suggested that I was mad to restuff the caps in such a common set as the TV22, however I do like my sets to look old, even on the inside. Anyway, there will evenyually be a time when TV22s that are not full of bright yellow poly caps, although strangely the supply of TV22s never seems to dry up. Also practicing the skill of restuffing capacitors in common sets has enabled me to gain a reputation that has opened up oportunities for me to restore other people's rare sets. A couple of points:- I see you have an electrolytic next to the big green resistor, it might get a bit too hot being that close. If the warm up time seems a bit long then you have to carefully bend the big green resistor closer to the thermistor (the black rod that looks like an unpainted resistor), you may have to melt the solder on the tags to achive this. The 16uF capacitor to the bottom right of your picture is probably open circuit. I'm not sure why they fail when the main smothing block is usually fine. Regarding those tiny 1nF waxies, what I do is slit along the length of them and unwrap the cardboard label. I then glue this around the new slightly larger capacitor, fill the ends with wax and solder them o the set with the gap in the label facing the tagboard in order to hide it. Ah yes, the Bush tag boards. Whilst I often say that the TV22 is not the best set to have as your first restoration from a technical point of view, it is at least very easy to service. If you had started on the equally common PYE B18T/LV20 you would have had a set with more reliable wound components, but with hard to service point-to-point construction built up in layers. It is much easier to connect a new component to the wrong place in such a set and not notice your mistake. Keep up the good work. Cheers Andy |
Re: My first telly TV22
Thanks Beery
I’ve read quite a bit on pros and cons of restuffing- I guess it’s the origional old axe story. As you say one day these TV22 will become rarer - like unmolested MG midgets so I think it’s worth preserving what can be preserved. Will have a go at slitting the small waxies. I think the blue electrolytic is more or less where it was when I found it , though it may have had longer leads and been standing further away from the tag board , I’ll have a look at it. |
Re: My first telly TV22
Re stuffing also forces me to slow down and work more methodically which is not my normal MO
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Re: My first telly TV22
Sorry just realised you are talking about the black electrolytic , that’s a temporary job till I get a better replacement , just don’t like to leave completely loose ends
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Re: My first telly TV22
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My first (and only) vintage TV was a Bush TV24 which is very similar to the TV22.
Although l did have some knowledge l don't know much about vintage TV sets so l started by replacing all the wax covered capacitors, including a couple of hidden ones that are easy to miss. These TV sets seem to last the decades of non-use very well, after replacing the wax capacitors mine powered up, with HT, but there was no picture. My friend who knows a lot more about these TV sets let me sweat for a week or so, trying various things, and then came round and got a raster (light on the screen) within thirty seconds. There's a little magnet on the neck of the tube called an "ion trap magnet" and it was 180deg out, turning it round brought the picture straight on. Also l expected a "snowstorm" on the screen and it was just white. I thought it must be faulty but apparently this is normal. When l eventually bought a converter the picture was very good. That was back in 2009 and the TV is still working, l turn it on every few months. Remarkably the tube is good, after 67 years. |
Re: My first telly TV22
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I’ve been chasing down more waxies. Discovered that there are some differences between my set and the trader sheet I have. There appears to be some additional components on the tag board that is mounted on the left side (looking from the front). The 8k resistor appears to be open circuit - it’s quite big any idea what power it is likely to be?
I guess this would have stopped the thing working. |
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