Welcome, i've created this channel so I can show and share the knowladge I've gained, and also learn from others.
I run Mullard Repairs, in South East London. Here’s where I’ll share some of the customer work I get in, showcase my projects, and share stories, from my experience, with being self employed!
From vintage rotary telephones, to vintage televisions! I restore them all!
New sub here... I used to do telecommunications repair in the 80-2017 this set reminds me of a grundig / phillips. But please get your self an safety transformer for your bench becouse some of those tv's have a hot chassie and i have heard of peeps getting killed off touching kv surronds.... but keep up the good work tho nice to see some one keeping these sets going...
@@MRJWC2332 glad you could join us! Welcome. Absolutely. I think it is a German set. Reminds me of the super Color spectra sets. Just to say, all my bench power points run off an isolation transformer so no risk of contact between mains. Always perform safe isolation, shorting capacitors etc. prove dead
3:45, it wouldn't work anyway because the audio carrier in system M is 4.5 MHz while in the UK it's 6.0 MHz, even if you took it to mainland Europe it woudn't work as it's PAL-BG which is 5.5 MHz, so you would get a picture but static for audio. But these were sold all over the world so I wouldn't be surprised if conversion was as simple as changing a jumper or something.
i usually find those blue philips caps pretty reliable, they do 'deform' with disuse but usually reform ok , theyre still made now in one form or another under the vishay name
nice beast, i once repaired a bush ctv194 that had similar looking chassis, but not identical, different front, had a mechanical tuner, only fault was shorted low voltage bridge rectifier and blown surge thermistor
@@The_Studioworkshop he like bammed into the tv while he was drunk and it fell screen first onto the floor and shattered the screen! Then he tried to put it in the recycling bin and when i came home my neighbour yelled at me about it saying you cannot put them in that bin!!! Im so angry and i dont know how the hell i'll be able to get a new one!!
Had one of these from new for 20 years, wore the tube out until it arced one final time. Was a TV and RGB monitor for a Spectrum +2, amazing picture for a portable. Great video.
Mrs Richards: "I paid for a room with a view !" Basil: (pointing to the lovely view) "That is Torquay, Madam ." Mrs Richards: "It's not good enough!" Basil: "May I ask what you were expecting to see out of a Torquay hotel bedroom window ? Sydney Opera House, perhaps? the Hanging Gardens of Babylon? Herds of wildebeest sweeping majestically past?..." Mrs Richards: "Don't be silly! I expect to be able to see the sea!" Basil: "You can see the sea, it's over there between the land and the sky." Mrs Richards: "I'm not satisfied. But I shall stay. But I expect a reduction." Basil: "Why?! Because Krakatoa's not erupting at the moment ?"
It is! First port of call is sorting lopt core… then I can tackle H stat HV divider. I always seem to find myself fixing these “no one will touch them” sets
I hope you do get time to complete your Homemade CRT TV - thats actually something I have had on my bucket list ever since reading about someone doing the exact same thing in an old Popular Electronics, Mechanix Illustrated or one of those type magazines as a kid. The image intensity dependent sync separator issue - have you tried a simple diode DC restorer before the sync separator to clamp the bottom of the sync pulses to a known level such as ground? If you have already included that or it doesn't apply, please disregard the comment! The reason I mention it is I remember way back when dedicated computer monitors were rare, I cobbled together one which initially had almost the identical problem until I restored the DC which was floating due to capacitive coupling in the video chain.
Thanks for the comment. I have played further with the sync RC network. I’ve found if I increase the HT to the video amplifier, from 150 to 200 volts, the picture appears with much more definition but also sync seems a lot more better. I’ve added a Diode in the sync chain but I can’t see any real noticeable difference. I can see if I feed the video directly into a small composite monitor that it is in fact the video which has the odd black smearing in it. It seems to be less noticeable with the brightness of the scope turned up. I wonder why that is happening? The peak to peak video might be too low, around 35 volts from the take off point into the sync separator. I’m not sure. Looking at the sync pulses on the scope, the slope looks spikey! Isn’t there an IC which puts out separate H V sync pulses you can buy? Just wondering as it would be fun to play with. I realise the actual pulses need to be quite high (peak to peak) for it to lock the oscillators
@@The_Studioworkshop The LM1881 is/was a common sync separator. Old stock in a DIP package is available from from vendors on ebay and other places. It doesnt have horiz sync out but you could use the burst to sync the horiz oscillator (or just the composite sync out). Smearing in the video: if its horizontal blur, that missing or high frequencies but should not mess up the sync. More likely: If it trails/smears bright or dark areas in the right direction, that can be non-linear clipping/saturation with the video signal going beyond the linear region of the tube or transistor. If you have vertical dark and light bands linked to brightness in different regions of the image, that can be depressed low freq response due to capacitive coupling in the video chain. That where a DC restorer is needed. Of course, can also be a confusing combination of the a mixture of the above. I would carefully follow the signal though the circuit with an oscilloscope. And use a camera or computer to create static picture with the issue you described so you can see whats happening without a live moving video constantly changing things. Good luck!
@@ElectromagneticVideosthanks for the informative comment. I don’t think it was the LM1881 that I was thinking of. This one specifically had h and v sync out… I’m not sure! I have vastly improved my sync sep. Firstly the overall video level was too low. Only 30 or 50v peak to peak. One of the reasons the sync was rubbish and changing in scenes was mainly caused by the pulses being quite weak, as well as my separator circuit not being so refined. I’ve substituted my ECC83 video and sync for an ECC85. Brought the peak to peak voltage well above 130v which is plenty. I’ve gone ahead and tested this directly on the CRT and it works amazingly - I did notice video was quite faint before but viewable. There seems to be far more definition at least. Scanlines etc. seems to have about 2mhz bandwidth… Sync is remarkably better. One thing I cannot sort is false frame lock, specifically connected to my pattern generator, or at least one of them. Sometimes it locks in place, other times it does not however on video from a camera or the Freeview box seems fine. Reading some of the old tv magazines suggests I could put a Signal type diode between a potential and my modulator (the cathode) in the CRT. I’m not sure exactly what this could improve. My current problem is dealing with hum bars which seem to affect frame, but in the video. When it locks at 50hz, large hum bars are evident. It’s not in the video, or was there when X-Y to the scope, no AC in any of my voltage supplies… I wonder if this is interference from one of the transformers. I am going to wire the deflection plates, and cathode with coax shielded cable… wonder if this will get rid.
@@The_Studioworkshop Staying all tube is way nicer than adding an IC so glad to hear changing the tubes helped. 2mHz is great - thats fairly typical for tube TVs - the resolution in those days was a lot less than we have come to expect. I'm not sure sure what they mean about the diode- could be just a voltage shifter? Hum bars when sync locks - the transformers is a very good guess. The bars may be there but not visible when sync is not locked. Try putting a steel plate between the transformer(s) and the CRT and see if that has an effect. It could even be something in the room - a nearby power power line one the side of the house maybe? If you need magnetic shielding, a lot of larger CRT tvs had some magnetic shielding around the front section of the CRT. I dont think it was real mu metal, but still probably something that was optimized for it. I would be careful with coax to make sure it can withstand the high voltages. In most cases the voltage swings are so high in tube stuff that interference picked up on those wires will have a negligible effect. Of course thats a general statement - only testing will tell! Good luck!
@@ElectromagneticVideosthanks for the reply. Various practical television diagrams which have a bias network for the CRT uses a signal diode, with one side connecting to the modulator point to the tube, with the anode/cathode referencing either B+ of the set or the reference for the network. I am using AC coupling to the CRT. I have noticed turning up brightness all the way makes the humbars barely noticeable… not sure what that means. I could try adding a cap to ground from my brightness control but doubt this will do anything. You’re likely right with it being transformer interference. I would like to try and prove this. I’ve made my CRT wires not so long so I’ll need to redo them. I would like to add coax going to the cathode and potentially deflection plates… really big seesaw peaks going to the tube but I suspect it should be ok. I’ll post a detailed video soon once I get time. One of the transformers has slightly worked itself loose so I’m going through all heavy mounted gear using locking washers and locktight
2:16 Europe isn't just Britbongistan, in Italy having only 4 channels was something people dealt with in the early to mid 70s. By the 1980s in Italy there were at least a dozen channels in a given area. You had 3 RAI channels, 3 Mediaset channels, TV Capodistria (in the North), TMC, Rete A, and a bunch of regional and local TV stations.
I was referring to the UK specifically. The main Channels stuck around until the early 2010s however we had freeview (digital TV), with over 100 channels on it, for 10 years at that point - not to mention catch up TV, which was brought in around 2010
@@The_StudioworkshopI see. In any case, such a TV made more sense in Italy, as there were already many channels broadcasting in analog. By the 2000s the entire spectrum was filled with various TV stations, mostly local and regional ones.
I had something similar years ago, I think it was $12 at the grocery store. It fit perfectly between the dash and center console of my car, and with a cassette adapter I could listen to TV while driving.
I used one of these for a while to test vintage computers since it was the only B&W TV I had. Worked fine up until it overheated on a hot day in my garage and the picture faded out. One day I will dig it back out and see what died inside it.
I remember these TVs, they were everywhere lol, I was forced to use one for a while as my main tv... I don't think they are really worth picking up anymore unless you want to make an osc for music of off it otherwise you can get pretty cheap Japanese market TVs in a similar size that are all in color, the one I got was a huge surprise - not only is it color but actually a trinitron tube with super crisp colors even though it was a no name! :D
that tv chassis looks familiar , i repaired one the same or similar, in the 90s, bush ctv 194 , not a lot wrong, cracked surge thermistor and shorted bridge rectifier.. you certainly need the manual to set up the line stage balancing ,, similar with philips G8s that use 2 transistors
This is an A823 colour chassis. From memory it was an early type. I worked on another set which used the same chassis branded Murphy, with a 22 inch CRT in it. They are power horses but do suffer occasional faults with shorted tant caps on low voltage rails, cracked joints etc. sometimes low voltage smoothing cap for the decoder fails as well as HT smoothing. Noisey transistors in IF cans
that is IF you can get one, or even just a circuit,, but dont blindly trust them, there can be errors or even production changes, you may have the wrong one for your particular device version!
Good point. Most old stuff, depending on where the set was made, you could be lucky. Thankfully you can get almost any service manual from vintage radio.com for UK stuff. Americans had Sams photofact. We had trader sheets if official manuals can’t be found etc. I was able to secure the official and trade version of a service manual for my 1938 pre war television
These aren't bad monitors when you get them to stop vertically rolling. I have a steepletone branded btv510 model which has an rca av input, so the mod you may want to do in the future should be possible)
Hi why do you put paint on the anode cap? This is not good practice. The only additional thing to use is silicon grease which some manufacturers used to provide an additional barrier to prevent tracking and therefore to stop the EHT leaking to earth.
As an anti removal seal. Many manufacturers and engineers do this, I’ve seen it done personally on other repairs, and it means I can tell when someone has removed the EHT cap, if it comes back for repair. Anti tamper is really important, especially when you deal with the general public. Once someone tried bringing back another monitor… claiming it was the same… but serial numbers were different, but most importantly did not have my repair sticker, or dab of paint on one of the screws etc. Silicone dielectric is used to prevent flashover and form good connections… that has nothing to do with what I’m doing here 😂 No reason why it should be considered not good practice. It’s between the top silicone and the glass - not contacting with the conductive anode. I also use nail varnish for converging rings.
The MK1 types. Both work great. Only frustrating thing is with the MKIIs is lack of proper scart which makes wiring up anything quite difficult… I modified the RGB port to carry Y and chroma to go into a small Svideo adapter, rather than drilling holes in casework etc
@@The_Studioworkshop The SCART in the MK1 can be a little troublesome as you know. I try and be as gentle as possible with the connector for that reason. I have not needed to reflow that yet. Mine has a minor fault in the shadow mask where there's an obvious single 'dead pixel', could be a a fault in the phosphor or just some dust but you can barely notice it. I'm glad I got in there last year and serviced the deflection yoke, caught some early signs of corrosion on some windings and taped up those problematic rubber spacers.
People put these down as junk, and they were junk. But I used one at camp, and it served its use well as a radio and television receiver. No electric power there, so its battery operated capability was the main reason I bought it for $20. I powered it with a car battery. It worked okay, but we didn't watch tv much at camp anyway. No such thing as streaming then either. 🇺🇸 version
@@captaintrips2980 I’m not sure if there were specific versions for the UK. You would think UK models wouldn’t have VHF for 625 lines but I had one back in the days with the switch. These aren’t exactly dependent on PAL and NTSC so a simple adjustment of V hold will make it work on USA tv.
@@captaintrips2980 In Ireland they used 625 lines on VHF but I think that was phased out many many years before these were made. I suppose the little bit more lines in picture we have, we technically have only 25FPS. I’m sure the actual TVL of the picture is less than 625 lines on this screen though!
Does this one really lack a composite input? That's a bit lame, I've seen a few of these and they all had one built in (which would definitely suggest that adding one to this should be straightforward). I occasionally use one of these to briefly test old 8 bit micros using the composite in (sometimes LCDs fail to pick up a bad composite signal that these have no trouble with).
Externally it does but I suspect placements on board. I haven’t looked properly yet but will likely be able to get something working within the week to share on RU-vid’s!
Absolutely - LCDs are unreliable with things with bad sync, in fact some later colour sets are too! Tends to be the later stuff with OSD functions from the early 2000s
@The_Studioworkshop Both, 5 was the last one, launched early 00's I think. Channel 4 was 83. Don't know if 5 left analog earlier, I thought they all went the same time. Last switch off was October '12.
@@IrishvintageTVRadio that’s right. Channel 5 was the last one to join. I never watched 5 which is why I couldn’t remember it. I am sure only two beeb channels and ITV were the only ones which remained until early 2010s. I suppose it all depends on where you are in the UK too. A quick google search showed different transmitters switched off at different times
@The_Studioworkshop That's right, switch off started around 05 I think. Channel 4 had eurotrash, so hard to forget when you were in you're early teens!
Amazing ! This TV set mays only tunning in UHF I norm analog brodcasts with PAL colour. Only in UHF, not in VHF used in Eire. This tv, maid not receve A norm disabled in January and February 1985, with the oldest analog standard of 405 lines used since 1930's years !
