Welcome to my channel that follows my adventures with all things to do with vintage electronics. I build and use tests gear that helps with my interest in radio restoration, radio building and amplifier building. I like valve technology and one of the things I like to do is find a new purpose for the many now redundant television valves that can be bought for no money at all. Check back regularly to see what I have been up to or better still subscribe to this channel.
Is there a particular reason for the grid (g1) being shunted to ground by the Cap 100n? In addition to increasing internal capacity obviously. Thank you.
No reason as such, but you really need to accurately measure the 1V differential to calculate GM. I know some constructors have used analogue meters so really your choice. Thanks for the feedback
Do not get sucked in by the cheap prices for the Asian variable autotransformers. SearchYT for their many, many defects... Under engineered, ratings over stated, wired incorrectly, on and on.
Some Asian products are good. I have many good products. They are good at making thing to specification. If you specify cheap then that is what you get. If the cheap auto transformers are 3 time cheaper than others on the market, then you will be getting what you pay for. I had great fun renovating this one so that is another a option to get a cheaper unit.
Ooo... I would not have used IPA to clean the coil wires, as it might melt the enamel isolation, causing shorts. Maybe just water and a little dish soap. If the brush is in bad condition, it is very difficult to find a replacement. You can not DIY an electric motor brush. They are simply made of the wrong material. I have posted a couple of threads about this and other variable autotransformer matters, but YT will not me add a link. So, I will post an additional reply with the search information and maybe YT will let that through? You will also find my threads on building a DIY isolation transformer from two transformers, placed back-to-back. You will need that. You will also need a Dim Bulb Limiter and Emergency Shut-Down Switch, which are super easy to DIY. Search YT. I think that you are going to really like having the separate connection box and current reading feature. Okay, I will now try to add the search information...
EEVBlog. My handle is t1d. Use the advanced search feature and limit it to my handle. Look at the my various titles to find those on this topic. Do well...
@@VintageandReclaimedElect Good luck I’ve just picked up a VHF54. This looks a bit of a challenge there are loads of hunts capacitors tucked away in some tight spaces. Not the best design but I’ll get it done.
i bought an old variac last year and thought it was bust until i noticed the original laquer on the wire under the wiper had never even been removed. brand new!
Not only are they being saved from the land fill but you could provide an eBay link for me to purchase one Buy It Now. Please and thank you. Great video.
I didn't think to buy a second hand one, I bought a new one. Ironic when you think my hobby is restoring/repairing vintage electronic equipment. However I've made up for it by buying a really old AVO signal generator and an AVO 7. The multimeter works fine and is used for aligning IF stages. The signal generator did need rebuilding. Great video.
Nice Video. I actually have built my own based on the same reference design. But not looking as good as yours... So far i have used a variac for the AC input to fine tune voltages. Not used high/low voltage selector som far. Considering a seperate bias voltage supply to keep it stable when i adjust tha variac. Maybe you would like to make a video covering testing common valves like EL84/EL34/ECC83/5881/6V6/6L6 ?
I’ve built models similar to that, yours looks very nice. Just think if you put that 1000 pounds into a valve stock? Tube testers were the means to sell tubes and install confidence. If I were running a service business a good stock would be of the greater value. Everyone loves a good tube tester in their shop. I can see a real purpose if you are selling tubes and you want to match them. Good job!
Thank you very much for the feedback. I know some testers are £1000, but mine was much less and a lot of fun to build. I tend to buy valves and collections and sell the ones I don't need. The tester is useful for that and will pay for itself in the long run.
New Subscriber here, look forward to your future projects. I'm currently restoring a vintage Hacker Sovereign II. Keeping away from the High Voltage stuff for the time being.
@@VintageandReclaimedElect I have seen some videos were they break of the little metal tab that is in-between the two screws on the hot side of either the the outlet or the switch and they say that if it's in parallel it will create a short and the set up should be in series. Hope that makes sense
I have one of these radios and the volume seems to not be working... I would love to visit you with it, as you have experience with it and i am scared of it! Im not sure if you accept visitors?! Thanks!
@@VintageandReclaimedElect no probs! Do you happen to know which valve is responsible for the volume? The part number, as that is the culprit for mine I think
Hi again. I finally got around to watching part 2 (it's been a busy week!). I agree with you about those Hunts capacitors. I now change them on sight - if they aren't faulty they soon will be. That said I think it's a good idea to re-test the radio after every one or two capacitor changes. I got lazy at one stage and started re-capping a whole chassis in one go and that was fine until the time the radio didn't work when I'd finished. Trying to back track and find out what I'd done took many frustrating hours. As I recall it was a dropped blob of solder. Anyway, I like your methodical approach. Myself, I would be happy enough to probe the voltage test points with the radio on. As you found out, it needs to warm up properly and stabilize before you check voltages. As for an RF signal generator, I got myself an old 1950's Leader sig gen for $50. I plugged it in and it worked fine. It would be a nice project to restore it though. I have since bought myself a Rigol "function generator" because the old Leader wouldn't stretch to FM frequencies but I still like the old Leader & use it for AM alignments. Speaking of which, the whistling you're hearing when tuning stations is pretty much an indication that it needs an IF alignment. Anyway I'm looking forward to seeing you design and build an amplifier or two using TV valves. Cheers
You are responsible for my methodical approach as I learnt form your experience. I did test every couple of capacitors and had to back track after I applied to much heat to one. I guessed the radio needed some alignment. I do now have a old valve based RF signal generator (Advance Components signal generator type D1D) to do up. It weights 10Kg but will help me if it is not too heavy to be useful. Ironically, the radio stopped that whistling after I took it back, but I have the option to go back and set up if needed. For now it is working very well.
This will be a great radio when it's finished. I recently restored a Bush VHF64 - the only one I have ever seen here in Australia. As we didn't het FM broadcasting here until the late 1970's, valve FM radios are a rarity here. Thanks for an enjoyable video.
Thank you for the feedback. I have been watching your channel and learning a lot. I have a Bush VHF 64 lined up for restoration. They sound great so had to get one.
Hi. I just discovered your channel and it looks like you will have some interesting stuff coming up so I subscribed. I agree, a dim lamp or dim bulb limiter is probably the first piece of kit you need if you're going to work on vintage electronics. I now have a variac but to be honest I only use it occasionally. I normally use a 60W globe with most vintage radios. Yes, it does drop the voltage to the set a bit initially but the degree of glow in the dim bulb gives a good visual indication of what's happening: You can see the initial surge of current as the rectifier valve starts up and the capacitors charge, see it dim off as they reach full charge and brighten up as the rest of the valves start to conduct. I still use the original one I made when I first started down the vintage radio rabbit hole and you can see it in nearly all my videos. Cheers
Thank you for this feedback. I love hearing what people are doing. I have a variac in the process of being restored. I'm building a system for prototyping valve based projects. 3 radios to do this year and also a valve based RF signal generator. Lots to do!
Looking forward to seeing that. The variac restoration should be interesting and it would be nice to have a restored good quality one as opposed to the cheap chinese one I (and many others) use. The signal generator should likewise be useful. I have an old valve based Leader that I've been using for years. I've never restored it but it's still working well. Prototyping valve circuits sounds interesting: I haven't got into that yes beyond sketching out some ideas.@@VintageandReclaimedElect
Thank you for this. I have been mulling over starting a YT channel of my own working with tube circuits and antique radio, but I have limited experience with both. Once I get a lab bench set up this will become my retirement project. Thanks for the clear explanation for how gm is measured. Didn't realize it was so simple.
Thank you for the comment. I have limited experience too, but I'm sharing my journey. I've learnt lots from the comments and it's good fun. Definitely go for it.
I also built Grant's tester and included my own changes. I removed the opto couplers for the meters and simply left the batteries in the two meters. I broke into this battery circuit and brought the wires out to a switch. When I use the tester I simply switch on the "meters" switch. There is no sign of the batteries dying. When they do it is a simple matter to open the case and change them. I also used a separate transformer for the heaters but included a rheostat to adjust the heater voltage to 6.3V. I haven't used the separate banana sockets but I am able to monitor various voltages via the sockets that are not in use. I have tested plenty of valves including 12A*7, 6L6, EL84, EL34,6V6, KT88 etc and have found a few with internal shorts and a few with low gm.
Be aware that the toroidal bolt in my build is insulated at the other end so that there is no risk of earthing both ends. If the bolt is earthed at both ends, then it will behave a s single turn winding. Although the volts will be low, the current will be high in the short circuit. This can damage the transformer.
Be aware that the toroidal bolt in my build is insulated at the other end so that there is no risk of earthing both ends. If the bolt is earthed at both ends, then it will behave a s single turn winding. Although the volts will be low, the current will be high in the short circuit. This can damage the transformer.
your final comments were eye opening that some people would ask about ht options they should stop and only use low voltage eg less than 12 volts or lower
these should give good results as they have 2 IF amplifiers, most usually had one, i have one of these with cracked case in the back of the shed to try and resurrect as and when i get chance to get to it!
@@VintageandReclaimedElect yep, the '64 is basically the 'big brother' of the '61, which was also available in wood case as VHF62, there were 2 ACDC models in 'similar' cabinets, VHF71 and VHF 72, but only one IF stage .. i have an EBS64 which is same case as VHF64 but an AM only MW plus 4 SW bands 'export' model with 'teleflic' dial
@@VintageandReclaimedElect make sure you check the grid 1 volts of the EL84 after its been on for a few minutes, they can suffer from grid current after many years of use and the grid creeping positive causing excessive anode current and possible component damage, many experienced 'engineers' restorers dont seem to know of this and i've not seen it mentioned in the various old servicing books i have, its a big problem especially with these small, close electrode spaced 'all glass' valves, i've come across this a lot ... it can make valves with good main emission completely unusable in normal valve circuitry,
@@VintageandReclaimedElect thing is it doesnt usually show any issues if it is developing grid current unless very severe, then you 'may' have distortion...it will mostly get hotter, the valve have shorter life and risk burning out the output transformer and/or mains transformer ..
Nice project. However, I would make some comments regarding safety. Firstly, when measuring continuity to ensure all of the metal parts in the case are connected, the standard is to use a continuity tester with 100mA test current. An ordinary multimeter will have a continuity current of only a few mA. Secondly, It is considered very bad practice to use the mounting bolt for a toroidal transformer as an earth point. If you accidentally earth the bottom of the bolt, you will create a shorted turn on your transformer which will in turn make a big bang. Thirdly, I suspect the push switch you are using for the gas test is not rated for a sufficiently high voltage to be safe (and indeed your toggle switches may only be rated at 125V - you should check). Finally, when making this kind of circuit, you really need to have a high quality multimeter with at minimum a CAT I rating and preferably CATII or CATIII. They are not super expensive and I recommend the Brymen BM235 as an excellent meter for less than £100. Also, (and this is just a personal view), I would have wired the grid voltage potentiometer the other way as the convention is to turn a knob anti-clockwise to make the situation 'safer'. Good luck with your new channel.
Thank you for the comments. Good point about earthing the centre bolt of the toroidal. I will place an annotation in the video and add a comment to the description, along with disconnecting the earth. The bolt in this project cannot be earthed at both ends. The transformer is bolted to a plywood base and that is fixed to the plastic base of the case via wooden standoffs. No metal mounting. There is a cavity between the underside of the plywood and the case. The bolt is confined in that cavity and no wires or metal exist in the cavity. The case has no holes drilled into it so the bolt and everything else is well insulated from the anything outside. I do have other multi-meters. CAT III to CAT IV. I have used them in this video but tend to go for my old academy meter. That too is CAT III. The CAT IV I have is good. I will certainly invest in a good continuity tester. The push switch is 250V 0.5A. Toggle switches are 250V, 3A. That is top end for my voltage and current draw tends to be no more then 30mA max. I have thought about wiring the grid pot the other way round for the reasons suggested by you I will do this when I remove the toroidal earth.
You should be able to download the schematic of my version of this tester here. github.com/ghallberg-nbtt/vintage_stuff/blob/main/my_version_schematic_tube_tester.jpg. Unless stated, the diodes are 1N4007. The fuse needs to be 500mA rather than 250mA. Be sure to check out Grant Willis' reference design. valveheaven.com/2015/03/an-inexpensive-easy-to-build-diy-valvetube-tester/
Thanks for the video's. I just found yoer channel. Very clear and calm explenation of everything. I agree with the safety you are mentioning. To start this hobby i bcollected al kind of tools and parts. Almost a complete workshop. But still i can't do much yet. First i have to let replace and test my ungrounded wall sockets 😄 As i have some tube radio's and amplifiers it is not safe enough to work on it because of my lack of knowledge. But i'm getting there soon.
That's great to hear that you are giving it a go. I too still need lots of test gear and knowledge. I am working on that. Glad you are taking safety first.
I have exactly the same radio, same vintage as me, 1957 origin. I’m more comfortable with digital software than analogue hardware, so the process looks out of my pay range. Any ideas what I try to do, or who to take it to and get it working again? And likely cost 😮? It was working about 20 years ago and has been dry ever since I think.
I guess it depends how you emotional attachment there is to the radio. Component wise this cost about £35. It only needed new caps and a new mains lead. Valves tend to be solid and of the least concern. Its the paper caps that are rubbish (They are made by Hunts). Electrolytics can dry out so best change them. Everything else should be solid after testing the mains and output transformer. The issue will be that this took about 18 hours of works and a vintage restorer will want around £200+, to cover labour. I really do know know of any, but there are some good Facebook groups that can point you in a good direction. Ironically, you only need basic soldering skills, a fundamental understanding of components and a good multi-meter. So some basic modern electronics kits will get you started with the skill set. There are some vintage books on valve radio design that will really help if you have deeper problems. You really need to be aware of the voltages in these old radios. The high tension in this radio was 250V+. They can be lethal. I ensure they are plugged before applying any probe. All probes are clipped securely place so my hands are away from the device. I have a current limiter in the system at all times. I also wear rubber soled shoes to eliminate any path to earth.
Thanks for the detailed reply. Yes, I was aware (by googling) of the voltages involved, hence the nervousness! Yes, I would very much like to get it fixed, it was with me through my childhood with Family Favourites BFPO on Sunday and Billy Cotton ... The added complication is that I'm in Spain with 230V with a tendency to surge at times, so will need to be careful with surge protectors should the moment arrive. Your videos are superb, so I may tentatively have a go, although my guess would be that there may be local specialists who are old-schooled, there's a lot of older tech out here. If I lived next door to you I'd happily drop the radio with £250 haha! Thanks again@@VintageandReclaimedElect
@@VintageandReclaimedElect be warned i had one of these that had an open circuit output transformer, and heard of quite a few other cases of them failing in these, likely caused by overcurrent in the EL84 due to 'leaky' coupling capacitor, or could just be a poor type.....although the EL84s themselves are known to go into 'grid current' after a few minutes of use and pass excess anode current, i've seen this a lot, even more so with UL41s and UL84s
Brilliant, love those BUSH radios, so gorgeous and brilliant engineering. My dad had a BUSH EBS-63, which he bought in the 60's, an export brand, very similar to this domestic model VHF-61. I am not an expert, but one day i hope to have this gem EBS-63 restored. The tubes are 2x EF89 (rf and if amplifier), ECH81, EBC81, EL84, EM81 and EZ80. The radio worked very well with ocassional repairs until 1983 and has not been operated since. I'm sure the paper caps and tubes will have to be checked and replaced. Thanks for sharing your restoration and great to see your VHF-61 working again. Best wishes from Vienna.
Thank you for the comment. I love this radio too and I really the memories that these restored radios bring back. I spend a good 2 hours with the owner of this radio as they recalled stories of family listing to this radio. With your radio I would suspect the tubes are fine. Tubes of the 1950-60's were made to last. I suspect it will be paper caps that need changing just as with this one.
@@VintageandReclaimedElectYes Sir. I hope the valves are good, in any case I’ve collected a spare set just in case. Meanwhile I have also made a Hot Chassis Plug, an idea shared by Mr.Caldeira on his YT channel, so as to avoid being zapped because the input cord is not polarised. Those piano type Band switches look elegant on your VHS-61 too. I share your joy in seeing the beauty come back to life. Cheers.
@@benoySimon EBS63 has an 'isolated' chassis, it uses a double wound mains transformer, the chassis should not be live regardless which way round the mains is connected, if it is, something is very wrong with it! i have a bigger version, EBS64, large wood case but same piano key control design
@@andygozzo72 - Yes indeed, you're absolutely right, on having a look at the circuit diagram, it does appear to be the isolated type. Thanks for your observation. This export model EBS63 has a wooden case and an unusual horizontal "spin-wheel" tuner, identical to the later model EBS66 which was apparently also in a wooden case. What a joy it brings just to see these lovely BUSH radios back in action. Best wishes.
@@benoySimon export models do occasionally turn up here in the UK and more of them seem to be Bush than any other brand, another one i have is EBS44L, supposedly one of the best ones they ever made, tuned RF amplifier stage and push pull output ,
Thank you for showing us this project. Putting it in a camera case is a bit of genius, it looks very smart. I have used this voltage multiplier supply for a valve radio project. Because the current draw is about 60ma I used 220uf capacitors, which gave around 250v under load. I also realised that this a potentially lethal supply. There is a large amount of capacitance,, which holds several joules and stays there for a long time after switching off. so I put bleeder resistors across each stage of the multiplier , the voltage drops away quickly after the power is switched off. It is easy to drop one’s guard after the power is switched off.
Thank you for the feedback. I hope I stressed safety enough in the videos. I have a strict procedure for connecting, powering and disconnecting, and that is for me using it. You really need to be respectful of what this can do to you. I do have a bleed resister in the voltage doubler.
As far as I know, the most important parameter of a valve, is the condition of the heated cathode. Only examining the state of the cathode can we decide whether a valve is rather new or used or heavily used. This should be the first stage of valve testing and everything else should come after that. And you can check the condition of the cathode is pretty easy by measuring the emission current at two points. One point at nominal heating voltage and an another at 60% of the nominal heating voltage. If the emission current does not drop below 50%, than the valve is good, if it drops below 10%-50% then the valve can be usable, below 10% percent it is bad.
They are a lovely sounding radio especially when you can control the tone. On mine which is exactly the same, has brown knobs on. It seems strange seeing them in white.
@@VintageandReclaimedElect Having a quick search on Google images, they seem to come with white and brown knobs, but everything else seem to be the same, you learn something new everyday 🤗 The bush vhf62 is exactly the same radio but in a wooden case, which looks very nice 👍
The Bush VHF 61 is a fantastic radio. I restored one just over a year ago and is my daily driver, with no problems. You have to change all the little hunts capacitors as they will have gone out of tolerance plus the plastic will have gone hard and are cracking or will crack as soon as you touch them. Thanks for the video.
Great project, very professional, and always leaves new possibilities to add new features to enhance it. Deeply appreciate your generosity to share it with all. My respects from PR.
That's a very good idea to enhance the features. We start planning , then making charges to improve the prototype...that's it's evolution of the first idea until we reach our personal needs. Again, thank you for sharing, it really looks great!
This is a great reference desin for a Valve/Tube tester. I would probably make a small addition to make a variable voltage on both high voltage and heater so it can test a wider range of valves/tubes, but that's mainly because I do have a wider range of voltages needed for testing what I work with. I think this is an invaluable tool and also a great project for anyone interested in getting into the valve/tube equipment hobby or even for more major restoration work.
Totally agree. You can use an external variable heater supply by connecting directly into the banana plugs to the valve. I am also making an external PSU to vary the screen volage to a much wider range. The limitation of this design is the variable in possible voltage combinations.
I think I will just use my variac on the ac input to lower the output for plate and screen to exactly what I need. With an external heater supply. Not very portable but I don't need to move it from my workshop.
