23rd Nov 2021, 10:02 am | #41 |
Heptode
Join Date: Jun 2006
Location: Ware, Hertfordshire, UK.
Posts: 988
|
Re: Another TV22
Hi Bren,
I'm glad you got there in the end. Broken leads on coils can be hard to spot. I'm sure I have spare aerial/RF cores for a TV22, but I won't be able to get to them until Christmas. Cheers Andy
__________________
www.youtube.com/user/andyvalve100 |
23rd Nov 2021, 2:11 pm | #42 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
Yes, it's just one of those things, we've all been there! That's great to hear Andy, keep me in mind for one but I'll scour elsewhere in the meantime, as you can imagine my patience in getting to the picture stage is now wearing thin!
I did manage to get a test tone through the speaker at one stage before the frame collapse had been sorted but all is silent now, I' m going to focus on the RF deck tonight and see if I can solve its issues. With luck the damaged core may not matter too much with the set being directly fed from the aurora. |
23rd Nov 2021, 10:15 pm | #43 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
Well this evening we have Test Card C of sorts, a very weak signal no doubt partly the fault of the missing core. I have removed the BIII converter which lead me to these results, presumably the BI/III switching was very dirty. I will have a think of what to do with the converter, I may sort it out at a later date and refit.
In the mean time I'm going to test the valves on the RF deck, they all look very well used. I know you can never judge just by looks but some of them do look like they've had a very hard life, it makes you wonder how long some of these sets were in use for. Judging by some of the old repairs prior to restoration this one looks like it was still being used into the 1970s. |
23rd Nov 2021, 10:55 pm | #44 |
Dekatron
Join Date: Sep 2006
Location: Kilmarnock, Ayrshire, UK.
Posts: 5,422
|
Re: Another TV22
Hi
At least you have somthing on screen and it can only get better. The oldest set I saw actually working in a home was a Pye V4 around 1970/71. It was used as a spare set in a bedroom and was very good. Another V4 was rescued from British Relays bin and was done up to test the "Vid boxes" which I converted to 625 lines. That was in 1971 as well.
__________________
Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member |
24th Nov 2021, 3:39 pm | #45 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
Yes I'm sure with some further attention to the RF deck it will be good. Interestingly I do have an RF deck for a TV12, I'm tempted to see how compatible it is with the TV22. Initial thoughts were that it wouldn't be at all, but then I recall the TV12AM which (if memory serves me right) utilised the same main deck as the TV22, however I don't know if there are still differences between the main deck on the 12AM and the 22. It would certainly be interesting to see whilst I source some cores and make further repairs to the RF deck.
|
24th Nov 2021, 7:02 pm | #46 |
Nonode
Join Date: Jun 2008
Location: Coningsby, Lincolnshire, UK.
Posts: 2,820
|
Re: Another TV22
I have tried a TV22 RF chassis in a TV12 before and it worked! The TV12’s RF chassis was having a few issues which turned out to be an OC coil, so I had the TV12 running like that for a while! Mine was the version with EF91’s and didn’t have the extra tag strip on the back that some others have.
Regards Lloyd |
24th Nov 2021, 7:13 pm | #47 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
Yes that's my thinking Lloyd, mine has EF80s with the tag board so I'd need to replace that bit of circuitry within the set which is only a few resistors and cap if I remember correctly.
Cheers Bren |
25th Nov 2021, 12:39 am | #48 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
Well tonight's workings have been checking the compatability of the TV12 RF chassis, it required nothing more than a capacitor and a few resistors fitting to the main deck, as well as some alterations to the capacitor feeding the ECL80 from the RF deck. I have had a look over the TV12 RF chassis and it is in very sound, untouched condition. The EF50 valve holders look good bar one which may still work okay. There are two broken tags on one of the B8A sockets (UL41) so one is on order, once this has been replaced we'll see what sort of life we get from it.
Unlike the TV22 RF deck, this one has been left untouched and never fiddled around with. I fear that the TV22 deck is going to take a fair amount of work to get it in good order, so the use of this TV12 deck will hopefully give me a good set for now whilst I can make repairs to the original deck as and when time and parts allow. |
25th Nov 2021, 10:55 am | #49 |
Dekatron
Join Date: Sep 2006
Location: Kilmarnock, Ayrshire, UK.
Posts: 5,422
|
Re: Another TV22
Hi.
The TV22 RF/IF deck is relatively simple, well laid out with easy access so personally I'd persevere with it. Working with it and repairing the deck is a very good learning curve and it will help your understanding of RF circuitry. With a good signal generator, a decent scope you'll be able to tie down the issues with little trouble. The chewed core should be able to be extracted reasonably easy and I'm sure If you put a wanted on the forum someone would be able to help. Using the TV12 deck will add in another bag of worms with fussy valves and perhaps dodgy bases.
__________________
Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member |
25th Nov 2021, 11:17 am | #50 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
Hi Trevor,
I'm certainly not going to give up on the EF80 RF deck, the idea of using the TV12 chassis is just to have the set working in the mean time. The TV12 RF deck is in much better shape so it should work with very little attention, should it prove to be full of faults then I shall go no further and focus solely on the EF80 chassis. I'm sure with care and attention it can be repaired, I'm suspecting one of the coils may be faulty which may explain why they had been messed around with. Tapping the tuning coil causes signal to come and go as well as tapping some of the EF80s, the first task is to clean all of the sockets more thoroughly and check the coils and go from there. |
25th Nov 2021, 6:06 pm | #51 |
Dekatron
Join Date: Sep 2006
Location: Kilmarnock, Ayrshire, UK.
Posts: 5,422
|
Re: Another TV22
Hi.
I've just repaired a TV22 deck today. It was multifaulted with at least half a dozen components faulty outwith the usual decouplers. This one had four resistors seriously off value, a 680ohm G2 feed to the 1st vision IF was low down to less than 300 ohms, the 150 and 33 ohm cathode resistors on the RF amp way low, the 0.0047uf mica decoupler was reading 10k and intermittently going open circuit, the 39k on the oscillator was over double its value. Although it worked the issue was intermittent fluctuating gain and crackling. A couple of minutes with the scope revealed where the problem lay, initially I thought it was dirty valve bases. Now running spot on (early EF91 type)
__________________
Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member |
18th Jan 2022, 10:49 pm | #52 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
Hi all,
I'm back on to the TV22 after having a break over Christmas. As discussed previously regarding the broken iron core I measured the good one and took to searching for a bit of ferrite rod of a similar size. I found some in almost the same diameter and set about grinding a hole to fit the screw. After this was completed I refitted to the set and managed to get the tuning much better but it was overall still quite poor. Looking underneath I noticed that the slugs of the two coils sitting closest to the contrast and interference limiter looked to also have been fiddled with in the past. Some adjustment of these has now brought the sound and vision closer together, but I don't have the maximum amount of sound where the vision is best. The vision side of things also isn't amazing, the picture has some ringing and is generally quite weak/fuzzy, the contrast control has to be turned almost fully clockwise and any backing off causes the picture to lose horizontal hold. I'll add some photos tomorrow, I'm very pleased with the progress that I'm now able to get a half decent picture along with some sound both of which I was having trouble with before, especially having them both at the same time. |
19th Jan 2022, 2:30 pm | #53 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
Hi all
I've attached a picture of the set now working as well as it currently can. The picture isn't bright at all and may well be due to a low emission CRT or overall poor gain on vision and low video output. The set that this CRT came from was in use until the mid 1970s and was the original so I knew this may have been a risk when fitting. I plan to run it for some hours and see how it improves, I previously had a PYE that was the same but after a week or two of running it for a few hours every day it came up to be an excellent tube. As can be seen in the image there is some ghosting on the picture and overall fuzz/noise. When I initially switched the set on today I was met without a picture once again and found that V4 EF80 (second stage vision IF) needs to be in a 'just right' position, so some investigation is needed into the socket itself - could be a poor/dirty contact or a break between the solder tag and valve contact. |
19th Jan 2022, 4:48 pm | #54 | ||
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
Posts: 2,535
|
Re: Another TV22
Quote:
Quote:
Steve
__________________
https://www.radiocraft.co.uk |
||
19th Jan 2022, 6:05 pm | #55 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
Hi Steve
The raster looks okay(ish) with the brightness turned up fully, but not as bright as I've seen with similar sets, some ballooning present when at the higher end so we'll have to wait and see how well it comes up. I do still suspect somewhat weak video output/gain at the IF stages especially with the contrast control needing to be fully clockwise in order to get any picture through. As I may have said previously, this has been one stubborn TV22 but I'm just happy that seeing some progress helps to give me the enthusiasm to carry on, I just hope the next one is better behaved. |
19th Jan 2022, 8:09 pm | #56 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
A somewhat better picture now I can get one in darkness, this one shows off the rather poor/fuzzy picture it has. Voltages and resistances look okay around the vision IF stages, could anyone suggest what to look over next? I can't seem to tune into a good clear picture at all, even when adjusting the channel selector - this is about as good as it gets. Sound is also still somewhat out but once I get a good picture on screen I can hopefully re-adjust the sound IF cores and bring it in along with the vision.
|
19th Jan 2022, 8:24 pm | #57 |
Octode
Join Date: Jun 2004
Location: Reading/Fakenham, UK.
Posts: 1,326
|
Re: Another TV22
Can't remember if you said you've peaked all three of the tuning controls at the back by the aerial input.
|
19th Jan 2022, 8:29 pm | #58 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
Hi Ian, yes I've peaked them all, as far as the tuning coils go it can't really get any better than where it is at now.
|
19th Jan 2022, 8:59 pm | #59 |
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
Posts: 2,535
|
Re: Another TV22
And did all three go through a definite peak and out the other side ?
__________________
https://www.radiocraft.co.uk |
19th Jan 2022, 9:22 pm | #60 |
Octode
Join Date: Feb 2010
Location: Leicester, UK.
Posts: 1,433
|
Re: Another TV22
Hi Steve, yes they did. I adjusted them over the peak initially then back to the strongest point on each. I'll have another go just to be sure but I'm quite certain they're adjusted to their best.
Cheers Bren |