Troubleshooting a Philips RF8 radio - Let's find out why it doesn't work!

[@elc.eng.ihsanalmutari9298]

It's a real pleasure watching these magical hands.

[@DavidTipton101]

Thanks Ihsan 🙂

[@martyh9309]

New workbench is fantastic!

[@DavidTipton101]

Thanks Marty, it should work better for me 🙂

[@jonathanreedpike]

I like your blend of diligence, pragmatism and humor, always a pleasure to watch you solve problems. The video production quality keeps getting better as well.

[@DavidTipton101]

Thanks Jonathan. I try 😊

[@Plons0Nard]

A great job once again. You are spoiling your customers 😊 (That's us, btw)

[@DavidTipton101]

Thanks Nard 😄

[@kennethgibbons366]

Well done as usual David. I note with pleasure how much more confident you are then when you first started and very little phases you these days. As usual it is always a pleasure and so looked forward to.

[@DavidTipton101]

Thanks Kenneth. I agree, I love learning and this hobby has been very good for me 👍🙂

[@johnrichardson7354]

Friday morning in Texas, and a video from Dave. What more does anyone need?

[@DavidTipton101]

Good morning in Texas John. Thank you 🙂

[@MrCarlsonsLab]

Fantastic looking bench Dave! Thanks for taking the time to share your videos too :^)

[@DavidTipton101]

Thanks Paul, I'm trying to keep up with you, not much hope thought👍😄

[@Donno308]

Hi David. A very nice job, as always. Interesting stuff about cathode bypass caps. I watched Uncle Doug's video - you're right - he's a good teacher. Love the new work bench. It would be SO nice to have everything conveniently at hand. One day ... I'm not really jealous. I'm not! Really! Mr. Carlson probably is though. Thanks for another Friday evening highlight 😀

[@DavidTipton101]

Hi Don, I devoured Uncle Doug's videos in my early radio restore days, it's a pity he only does amps and not the full radio. I somehow remembered his video on bypass caps and found it in a few minutes to refresh my memory. The new bench is working well at the moment, I'm struggling with new camera mounts and LED lighting but will get it sorted in due time. Thanks Don 😊

[@Donno308]

@@DavidTipton101 Hi David. Yes I have trouble with LED lights strobing in the videos. I've got a couple of flouros over the bench & use LEDs as infill. They're ok strobe wise so long as I keep them some distance away. I'm still experimenting with the overhead cam. At the moment it's fixed position and I just move the chassis under it. I was getting too much camera shake otherwise. Cheers

[@DavidTipton101]

​@Donno308 Your use of the overhead cam did not go unnoticed Don.

[@brianwood5220]

Thanks Dave. It's a pleasure to watch you work. Have a great weekend.

[@DavidTipton101]

Thank you for your support Brian 👍🙂

[@cliffjones7868]

I am impressed. With the step by step detailed explanations, clear voice. I learned a lot about it. The reasons for the resistors and caps were completely understood. Thank you, I wish in the mid 60s I had you in my teen years for a teacher. Thanks!

[@DavidTipton101]

Glad it was helpful Cliff, thank you 👍😊

[@MarkMcCluney]

Blimey! Roy and HG are still going? They've got a lot of Ozzie staying power. Thanks Dave, this was another very enjoyable and instructive trek. That sig gen is a beauty! Thanks again mate.

[@DavidTipton101]

Yeah, they are still going, just a bit older now 😄 Thanks Mark.

[@daleburrell6273]

...the word is: "AUSSIE"...(!)

[@radio-ged4626]

Nice to see a different approach to working with valve equipment. Usually see restoration, solving problems along the way. But this is more real, dealing with reported faults by the owner. As an ex- repair and service engineer this is more like what I used to do. Except the customer would be less descriptive and more emotional if you get what I mean 😊

[@DavidTipton101]

Haha... yes I know what you mean radio-ged. It was a good exercise to just do the troubleshooting and this one had an unusual fault which made it more interesting 🙂

[@stephengorin3059]

Love the new working bench, every thing at hand.

[@DavidTipton101]

Yes, it will need some adjustment as I go along but excited to use it 🙂

[@jogden6632]

Dave, new work station looks good. Love that you included mains for radios in North America!

[@DavidTipton101]

Thanks Jason, I have some 120 Volt test gear as well 🙂

[@stephengorin3059]

Great work on the philips FR8, Nice to see another one of these radio grams restored. As with the electrolitic caps i have found that the HT pins are a little bit close to the chassie. The ones i have done i have "nibbled" the chassie to give the HT pins a bit more clearance and not short out to ground. Restinging any radio a final trick is to paint the knot s with nail varnish ( a old bottle will last for ages ). This is obsorbed buy the dial cord and stops the knot from working loose. Great work David , Keep up the good work and as usual i will be looking forward to your next adventure.

[@DavidTipton101]

Hi Stephen, thanks. Yes I did nibble away at the edge in one spot and filled around the terminals with liquid insulation tape. I did put nail polish on the dial sting knots, I always do. Cheers 🙂

[@JerryEricsson]

Thanks for the video, it is always a great morning when I can have Coffee With Dave! Update - Saw my Dr. and I am still cancer free 2.5 years after loosing my right kidney to cancer. Next week it would have been 55 years of wedded bliss for my good wife and I, I lost her to cancer 4 years ago. Funny how much of that damn disease is around, perhaps it is just that we now live long enough for it to develop or something like that; who knows....

[@DavidTipton101]

Thanks Jerry. Well done staying cancer free, an awful disease. Living longer does mean we are more likely to develop age related diseases ☹️

[@knifeswitch5973]

Always learn something valuable from your videos Dave. Was great to lay in bed a little longer this morning and watch this one. New setup looks great. ❤

[@DavidTipton101]

Thanks Knifeswitch. I'm looking forward to using the new bench setup, a bigger bench as well 👍🙂

[@haythamchannel3553]

Good morning David. Great work

[@DavidTipton101]

Good morning Haytham, thank you 🙂

[@electronicsoldandnew]

Another “Good Friday” for me 😊 Who says you only have a Good Friday at Easter? Also learnt something I didn’t know: 360million pigs????!!! Thanks again Dave. Have a great weekend.

[@DavidTipton101]

Haha... thanks Manuel. Yes, lots of feral pigs roaming about, I think it's more like 20 something million... and about one million camels 😊

[@clasicradiolover]

That's a lot of ham.

[@catey62]

@@clasicradiolover Lol, with Dave's senses of humour, there's always plenty of ham on this channel. 😂

[@clasicradiolover]

@catey62 I rather think he's usually deadpan, but I loved the one in which he was working for his grandchildren

[@dogribmoon]

The new work space looks really functional. You will save so much time not having to get equipment set up and put away!

[@DavidTipton101]

It was too much trouble setting up equipment all the time and I would avoid it if there was another way. Thanks dogribmoon 👍

[@TobiasThede]

A fresh Video from David,the morning couldnt be better,on this raining day in germany.

[@DavidTipton101]

Thanks Tobias 🙂

[@tubeDude48]

Nice layout on the bench! 👍 YUP! I follow Uncle Doug as well. So glad to see you use DeoxIT Fader F for POTs! So many, (so called) repair people will use plain old contact cleaner, that in time, will form a film, and have the same problem re-appear!

[@DavidTipton101]

Thanks TubeDude. Yes, and used sparingly it works very well 👍

[@ralphmans]

David, nice to see you again, I was getting worried, welcome back.

[@DavidTipton101]

I'm bang on schedule Ralph, a video every three weeks. Thanks 👍😊

[@hazevthewolf178]

Your videos are just getting better and better. I find them really relaxing to watch. Kudos for the repair job that you did on this one.

[@DavidTipton101]

Thank you Mr Wolf 🙂

[@martinoakley6651]

As always, brilliant work and I always learn something. The cartridge modification was genius and will prompt me to look at a similar issue on my Bush radiogram. Looking forward to the next Radio Adventure!

[@DavidTipton101]

Thanks Martin. The cart mod worked well and sounds great even with these cheap cartridges from China 👍🙂

[@paulziminskin2ghr282]

Nice job Dave. You got lucky with that IF transformer ,That would have been a real bear if it needed to be rewound ,take care Dave

[@DavidTipton101]

Thanks Paul, I have a spare so it would have been OK either way. It's the antenna induction tuning coil 👍🙂

[@MCML50]

Hi David, i must say that you nailed it again a very nice job dan.👍👍.

[@DavidTipton101]

Thanks Claes 🙂

[@jamesbruno5896]

New bench looks great & you went above expectations on the repairs!

[@DavidTipton101]

Thanks James 👍🙂

[@ibrahimkocaalioglu]

Good job done. You are really an expert. Your Olympic team was very succesfull as well. 🥇

[@DavidTipton101]

Thanks Ibrahim. We are very proud of our Olympic team, thay have worked hard 😊

[@mikecass8306]

Great repair, love the new workbench, thanks David for another great stream 😃

[@DavidTipton101]

Thanks Mike 🙂

[@chrissmith7655]

Hi Dave , yet another super job and learn from every one of your uploads. Many thanks from UK.

[@DavidTipton101]

Thanks Chris 🙂

[@aaax9410]

Hi Dave great video , have followed UncleDoug for years , learnt a lot from him now learning a lot from you on radio , also from the South East cheers mate :)

[@DavidTipton101]

Uncle Doug was a big help when I started out, he explains things well. Damn cold here at the moment 🙂

[@aaax9410]

@@DavidTipton101 Heater is on mate lol

[@jims2222]

I also learn something from each one of your videos. Thank you Dave.

[@DavidTipton101]

Thank you Jim, me too 🙂

[@Jan_Talcott_100]

I haven't even watched the complete video yet... I want your new work station. It's fantastic!!

[@DavidTipton101]

Haha... thanks Jan 👍🙂

[@Antony_Jenner]

Nice one Dave, I've got one of those Philips boards fitted in an old South Australian Railways telephony box. Worked a treat when it was the workshop amp running into some vintage Richard Allen speakers. Thanks for the video. Oh and got to love Rampaging Roy Slaven and H G Nelson

[@DavidTipton101]

Yep, the set works well as an amp. I don't know how long Roy and HG have been going, it seems like an age. Thanks Antony 🙂

[@neilsradios]

Nice work as ever, especially the switch. Whenever I dismantle one of those rotary switches we end up with a long gap between video sections and editing out of many words that can't be put on KZbin 🙂

[@DavidTipton101]

Haha... I can imagine Neil. This one was very easy, I was surprised it went back together without any effort 👍🙂

[@Buzz1151]

Hi David...that was a good repair, and cheap too! bravo!👏👏 Dickel has a joke for you below. A bald guy sees David Tipton at the local pub enjoying a pint and walks up to him , and asks politely, "Hey, mate, I'm new in town. Do you know where I can buy a toupee?" David replies "Not off the top of my head."🤣😂😁

[@DavidTipton101]

Hi Buzz, thanks. Haha... that's a good one. Dickel is way funnier than you and I put together 😅 A new video from you just popped up, a coffee is in order while I watch it 📺... bit early for a beer ☹️🍻

[@Buzz1151]

@@DavidTipton101 🍺🍺🍺🍺

[@hestheMaster]

You not only are a great electronics restorer David but you watch the same YTer's as I do. This is one great community of vintage tech guys showing how it's done here on KZbin. The owner was probably estatic about you getting her up and running like a champ again. Steve from Illinois, USA

[@DavidTipton101]

Hi Steve, I totally agree, the fellow YT's I have interacted have been pleasant and helpful. The owner was very happy with the result 🙂

[@chriskilby5300]

Hi Dave loved this adventure so many faults to fix. I've always been into electronics as a hobby. I first started playing with valve radios (lucky I'm still alive)at about 13 yo. I am close to retirement and wanting to get back into it. I've built up quite a few radios and test equipment. Your videos are such a wealth of knowledge. Don and Frank also great inspiration. Thanks again Dave.cheers

[@DavidTipton101]

Thank you Chris. All the best in retirement when you get there and a new hobby to enjoy 🙂

[@ceebee23]

The work bench is awesome .... and as always a great job David!!!!!!

[@DavidTipton101]

Thanks Chris, I happy with my bench so far, I might tweak it a bit but it's working OK so far 👍🙂

[@ChuckKirchner-se6ib]

You can't go wrong with Uncle Doug. He's one of the best!! Cheers, Dave

[@DavidTipton101]

Absolutely, an outstanding teacher and a perfectionist as well. Thanks Chuck 👍😊

[@YellowJello57]

Great stuff as always, David.

[@DavidTipton101]

Thanks H 🙂

[@josephmagedanz4070]

Nice work with the radio, and, yes, I learn something from each of your videos, too (and from Uncle Doug, too). Thanks for sharing.

[@DavidTipton101]

Hi Joseph, Uncle Doug was very helpful explaining how how the amp stage and valves worked. I think you and I both learn something when I do a radio 👍😄

[@ellesmerewildwood4858]

Well, you do realize that this success will just add to your reputation for being the Montgomery Scott of radio repair.

[@DavidTipton101]

"Beam me up Scotty" 😄 Thanks Ellesmere.

[@clasicradiolover]

He is pretty good.

[@superhet7281]

Dave’s better than that - he’s the Mr. Spock of radio repair!

[@mrgunn2726]

A fine Tippton treat to enjoy with my morning coffee. Well done!

[@DavidTipton101]

Thank you mrgunn 🙂

[@LarryDeSilva64]

wow you really outdid yourself troubleshooting this radio. With problems I would never figure out . But you took them one at a time in your own methodical approach. Thanks for a great video.

[@DavidTipton101]

Thanks Larry 🙂

[@scask]

Nice new bench Mr David "Carlson" Tipton...😁

[@DavidTipton101]

Long overdue 😊 Thanks Scask.

[@scask]

Very posh (Scask aka Darren from Droitwich) 😉

[@DavidTipton101]

Hi Darren 👋😊

[@theprisonernumbersix996]

Encore un super travail et une video passionnante , merci David. "Be Seeing You" ! N°6 👌

[@DavidTipton101]

Thanks you N°6 🙂

[@michaelmiller641]

Fantastic video! Was that am? If so superb quality and bandpass tuning!

[@DavidTipton101]

Thank you Michael. Yes AM only this radio 😊

[@chrisrobson8540]

Fantastic repair as usual....love to see a full restore on your cabinet

[@DavidTipton101]

Hi Chris, That is my plan 👍🙂

[@ShannonFerguson]

Your new setup looks awesome!

[@DavidTipton101]

Thanks Shannon 👍🙂

[@hooshangyadegar1250]

I enjoy watching this video .❤

[@DavidTipton101]

Thank you Hooshang 🙂

[@richb419]

Hi Dave, nice work as always! Rich from across the pond

[@DavidTipton101]

Thanks Rich 🙂

[@stanleycostello9610]

🎶 Somewhere my love, there will be songs to sing." 🎶 With David at the helm, we can expect the best. (I have this album.) Have a good weekend.

[@DavidTipton101]

It must be a best seller album Stanley 👍😄 Thank you.

[@stanleycostello9610]

@@DavidTipton101 I remember my parents went to see "Doctor Zhivago." The women's fashions had a Russian theme that year, so my Mom had a mink hat. They went to a fine restaurant and saw the movie at the Trans-Lux theatre. 70 mm. My Dad bought the sound track from the movie.

[@DavidTipton101]

70mm was fantastic, I saw The Great Race in 70mm, it used three projectors I think, why don't they do it anymore. It sounds like it was a good night for your Mom and Dad 🙂

[@stanleycostello9610]

@@DavidTipton101I saw "Camelot" in 70 mm. It was magnificent.

[@roberthart8933]

Hi David. This is a great video. I’m amazed at your patience and detail. The tuner would make me bauk, and pulling the switch apart and fixing the on off switch are great examples to follow. This looks like a fine example of 60’s Philips design, and I remember that white shielded cable . I’m surprised the unit uses msp speakers (awa). Philips used to make really good speakers. I used to buy them to make hi-fi speaker units. In fact I still have my 1974 made boxes with Philips 12 inch drivers. The bass is really good.

[@DavidTipton101]

I'm a bit odd I think, I was excited to get into the tuner and see what was wrong with it, it didn't work so nothing to lose. The switch was surprisingly easy to reassemble as well. That's a good point about the speakers, I hadn't thought about it. This Philips chassis works very well and the sound for the radiogram is better than most in the era. Thanks Robert 🙂

[@ChrisSwenson]

Hi David. Where do I begin? Such a good video, on all levels; THOROUGH (all caps!), excellent camera work (as usual), presentation, superb detective work, walking us through the journey, the "nice" Mission Impossible typing touch, and the satisfying summary. BTW: starting off with your work station improvements, brings back youth memories of sharing "what I got" with friends - the day after Christmas. It's Labor Day in the USA, so I'm enjoying my day off with the added treat of anticipating the viewing of your "next" video, which you downloaded 3 days ago. Fine Job David! -Chris

[@DavidTipton101]

Thank you Chris. I'm very glad you enjoyed it. I trust you enjoyed you day off 🙂

[@hbhmhbhm]

Great work on the Philips and the new bench looks great too!

[@DavidTipton101]

I'm very happy to finally get the new bench together, I have been planning it for a year😄 Thanks @hbhmhbhm.

[@ricke.2205]

One of the many things that amazes me about radios, is the never ending variety of radio circuitry design. Not to mention, the variety of the overall designs of radios. Limited only by the manufacturer's technical knowledge and imagination.

[@DavidTipton101]

Yes, many ways for doing the same thing with similar results. Thanks Rick 👍🙂

[@nathkrupa3463]

Good work David sir you are awesome ❤😊❤😊thanks for sharing this video sir 😊😊😊❤❤

[@DavidTipton101]

Thanks Nath. my pleasure 👍🙂

[@erikdenhouter]

Nice repair David. What shows for me is that not all Philips are a pita to work on. Nicely open, easy to reach. Even the dial cord was simplicity itself. And the dial accuracy was the cherry on that cake

[@DavidTipton101]

I don't mind these Philips sets at all Erik. I think it was designed in Australia, not sure. Thanks 😊

[@Ragnar8504]

I think the larger Philips sets were generally decent to work on, the small ones are the real pain.

[@erikdenhouter]

@@Ragnar8504 I can back that up with my ever lasting repair on a B2X63U. Lacking the experience in tubeland, it scares the hell out of me to work live on it.

[@Ragnar8504]

@@erikdenhouter In that case I'll sometimes use probes that I can clip onto points while the radio is off, then turn the radio on and do my measurements. Doesn't work for aligning the set though, only for checking voltages.

[@erikdenhouter]

@@Ragnar8504 ☝Yes, that is almost the only way to do it safe. Still I cannot put my finger on it, need so many measurements, and the lack of experience in tubes doesn't tell me what to expect where. I gave up a half year ago 😖 Some day I will pick it up again....

[@paulsto6516]

Good show, man!

[@DavidTipton101]

Glad you enjoyed it Paul, thank you 😊

[@TheUltimateRecycler]

Great job as usual Dave! I like the sneaky way you've been able to free up space in cupboards for more radios by having a bigger workbench for all the test gear! Don't worry - I won't tell Karen of your cunning plan! 😉🤣

[@DavidTipton101]

Thanks Chris. Ahh... yes, we men need to keep one step ahead don't we 😅

[@Joe-KN4IFI]

Cracker Jack job David. Always a pleasure to watch your work. 73 Joe

[@DavidTipton101]

Thanks Joe 🙂

[@JonRig]

Great vid - lot's of fantastic insights and that little broken wire in the can was a real lucky find! Fascinating! And the new workbench looks great! Well done on that!!

[@DavidTipton101]

Thanks John. It was good I could repair the coil, it would be tricky to rewind 🙂

[@JonRig]

@@DavidTipton101 One things for sure - if anyone could rewind a coil it would be you!!! You are the master at that, given the magic you hace done with transformers and speakers!!! Stunning work!

[@greggsvintageworkshop8974]

Really nice troubleshooting techniques David! You have it playing very nicely now for your friend. Nice repair on the stylus as well!

[@DavidTipton101]

Thanks Gregg 😊

[@johnburns6422]

Philips drive cord systems/ you are a Brave Man , very good job well done , Many Thanks ☘☘☘☘☘

[@DavidTipton101]

A piece of cake that one John. Thanks 👍🙂

[@lyntonprescott3412]

Nice one David. Hope you and the family are all well. Lynton

[@DavidTipton101]

Yes we are, thank you Lyndon 🙂

[@andyfairman7812]

Fantastic as always! Thanks Dave!

[@DavidTipton101]

Thanks Andy 🙂

[@alpcns]

Thanks David - top work, as usual. That device sounds really good now. Many naughty caps!

[@DavidTipton101]

They are a good radio thanks alpcns 😊

[@davidhamm5626]

I like the segment intros, It's like of like mission "possible" ! Great work Sir.

[@DavidTipton101]

Haha... it was a bit, I must be having flashbacks 😅 Thanks David.

[@seankearney2592]

Nice one Dave,as always Your Magic Hands works Wonders.....

[@DavidTipton101]

Thank you Sean 🙂

[@wayneshirey6999]

Nice work as usual. I'd love to see a video of your putting that snazzy new workstation together.

[@DavidTipton101]

Haha... it took me a week to put it together Wayne, it would have been a long video with a lot of beeps 😄

[@matambale]

Loved it, your videos are always a treat, thanks David.

[@DavidTipton101]

Thank you Matambale 🙂

[@mackfisher4487]

Grate job David, your new test bench looks good. The 120VAC us receptacle is a nice touch how about having up for on, and down for off the way we do it.

[@DavidTipton101]

Haha... I didn't think of that 😄 Thanks Mack.

[@sheldonlatimer6688]

Once again great job well done

[@DavidTipton101]

Thanks Sheldon 🙂

[@EsotericArctos]

I love seeing these old radios brought back to life. Regarding the enameled cable, I was taught that a hot soldering iron is the best way to melt the enamel and tin it, and that seems to work for me on all I have done. It's kind of a shame that the AM band was completely renumbered. I've found virtually all early Australian radios only have the station call signs on the dial, and virtually never have the actual frequency. Not sure why Australian radios were done that way. Most Eu and US radios had the actual frequency or wavelength on the dial. Still great to get them working though as modern radios just don't sound the same

[@DavidTipton101]

I haven't always had success using an iron on the enamel, I really didn't need to remove any as the end still had solder on it. I couldn't see it as well as the camera showed. We knew the stations by the callsign, no need to remember the frequency. It was a good system. If I wanted to listen to a station I could select it from the dial and not search for it roughly about 'there' on the dial. Some radios had the frequency printed along the bottom but it wasn't really needed. Thanks Brendan 🙂

[@billnicholson2470]

Really nice workstation David. Great job on the radio detective work as always. 73 de KB7ICI.....Bill

[@DavidTipton101]

Thank you Bill 🙂

[@abcsd1254]

Very interesting that the caps in the cabinet were Ducon when the amp looked like all Philips. I wonder if they assembled the Radiogram in Australia with components made in Holland.

[@DavidTipton101]

Good point @abcsd1254, I have no idea 🤔

[@paulgreen3212]

Hi Dave been watching your show for a long time, loving what you do, keep up the good work thanks . Paul uk london greenwich

[@DavidTipton101]

Awesome, thank you Paul, I'm glad you enjoy it 🙂

[@iantyler4045]

Another triumph. That ceramic cartridge hack is brilliant. The Chinese ones are a very poor copy, designed to look the part and that's all (like most of their stuff!). Your workshop looks so neat and tidy. It's given me the inspiration to redo mine. Cheers.

[@DavidTipton101]

Yes, the carts are cheap, you could get the Pfanstiehl cartridge the Chinese copied for a little bit more if you were serious, I might get a few myself 🙂

[@edwardhannigan6324]

Fab job, great to follow and learn..Take care..Ed..UK..😃

[@DavidTipton101]

Thanks Ed 🙂

[@perunut4656]

Great video, really interesting to see how you fault find, particularly with high voltages. Only thing I have here thats high voltage is my inverter, and the original one had an internal arcing fault after a few weeks use, but was told by the manufacturer not to touch it :)

[@DavidTipton101]

Thanks Peru Nut. That sounds like good advice ☹️

[@mikesam347]

David, You did a great job repairing that switch. I could have taken it apart, but it definitely would never have worked again. ://

[@DavidTipton101]

It went back together very easily, I was surprised when it did. Thanks Mike 😊

[@ladamurni]

Nice one David, I enjoyed watching it!

[@DavidTipton101]

Thank you ladamurni 🙂

[@DiscoverEngland-ln7lj]

Great Video - thank you

[@DavidTipton101]

Glad you enjoyed it, thank you Discover 😊

[@madrafboy]

You're a star Dave. Anther good video mate.

[@DavidTipton101]

Thank you John 😊

[@Steven_Bennett_YT]

Can I give a bit more info about cathode bypass David. Back in the 20's and 30's radios used valves that had no cathode, only a glowing wire called the filament to emit electrons. Both mains and battery sets had to use an extra battery called a grid bias, or C battery, which provided the negative voltage to keep the grid more negative than the filament, or the filament more positive than the grid, whichever way you want to view it. The reason for the extra battery was that the indirectly heated valve, with an electrically isolated cathode, had yet to be invented so all the valve's filaments were joined together via the A battery or Low Tension supply. Then once indirectly heated valves, with cathodes, were available someone came up with the idea of including a resistor in the cathode circuit that could use the cathode current flow to raise the cathode voltage, known as self bias - individually for each valve. Good idea so far but the resistor created a large amount of negative feedback from DC to higher frequencies, greatly reducing the stage gain. Adding a cathode bypass capacitor virtually eliminated the negative feedback from low frequencies, say 20Hz to the top of the audio band, say 20KHz and higher. In other words the capacitor acts like a short circuit at all audio frequencies, maximising AC gain but the capacitor is an infinite resistance at DC leaving the cathode resistor to continue to provide DC negative feedback, which stabilises the DC operating point of the valve-tube.

[@DavidTipton101]

Nice, thanks Steven. That is perfectly presented and understood 👍🙂

[@Peugeot306]

Good evening David.

[@DavidTipton101]

Morning Paul 🌅

[@jimburns348]

Great video David. Your sleuthing ability would rival Clouseau.

[@DavidTipton101]

Absolutely, I based my life on his teachings 😅 Thanks Jim.

[@clasicradiolover]

Hey guy. I love that piece by Glenn Miller. I think I first noticed it on an episode of Doctor Who with Rose.

[@DavidTipton101]

Here you go classical: kzbin.info/www/bejne/lXSsXmN7lM-mm9U

[@clasicradiolover]

@DavidTipton101 Thanks. I have it on my Spotify list, too. For a 59 year old, I have some esoteric tastes. I listen to my Grandparents and parents eras as well as my own. And in foreign languages. Especially Spanish. And the old time radio shows before TV

[@1974UTuber]

I thought for sure it was gonna be a case of a cracked board. Nce job as always

[@DavidTipton101]

Well, yes, it could have been 1974UTuber. Thanks 👍🙂

[@OIE82]

Very well done, repair and video. One thing would add educational benefit, and that would be to show where you get the specs for the adjusting and alignment. Eg. How did you know that the dial pointer should be on what mark at what frequency? The cutting back and forth would require more video editing, I guess. Anyways, thank you for all the great content.

[@DavidTipton101]

Good point Odyssey, I put a link to the Schematic in the description below the video. I have done these so many times I forgot to show what I was doing. Thanks 👍🙂

[@OIE82]

@@DavidTipton101 Thanks for the link. More than anything else, finding a new source that may have complete documentation is always a plus. Most of the time I am happy with a close schematic.🙂

[@ralphj4012]

Thorough, as always, though I did expect to see vertical smoothing capacitor clips, chassis drilled to accommodate, painted black and with white Letraset applied to reproduce any obscured lettering, ho, ho.

[@DavidTipton101]

Haha... thanks ralph 😄

[@lookoutleo]

I love watching you do these great restorations , wish you could do me a tuner amp so could connect my record player and listen to my Jimmy shand 78s

[@DavidTipton101]

Jimmy Shand, the accordion player! That's an old one Leo 🙂

[@lookoutleo]

@@DavidTipton101 I have loads of 78s from the 20s on, would love to hear them with valves , in mean time I listen to them with my 1980 music centre with 60s speakers :) I have loads of Ambrose and his orchestra , pop music of the 30s :) so modern

[@decoder6379]

Я регуляторы промываю изопропиловым спиртом. Тоже хорошо помогает. Лайк поставил.

[@DavidTipton101]

Спасибо, ДЕКОДЕР 👍🙂

[@nzs316]

"Dr.Zhivago" is on your top of list, must listen to, music! Thinking back that there was a woman that got run over in the train scene and there was no interruption in the filming and the room filled with ice during the winter...heck i was 5 when that came out.

[@DavidTipton101]

Hi Neil. I don't think I have seen the film. I do recall a woman trying to board the train fell under the train and was injured. I can't remember if they kept that bit of footage in or not 🙂

[@nzs316]

@@DavidTipton101 they kept the scene where she tried to climb on the train and then falls but they don’t show her going under the train. Kinda eerie to witness a persons final moments.

[@neilforbes416]

37:00 You made "light work" of this set! LOL😁

[@DavidTipton101]

I did! 🙂

[@neilforbes416]

@@DavidTipton101 LOL

[@ShannonFerguson]

Dinah Washington ❤

[@DavidTipton101]

Agreed 👍🙂

[@SuperFredAZ]

Yes, for a high gain (gm or Mu) the gain reduces the larger the cathode resistor if you bypass the cathode resistor. The cathode resistor is there to provide negative bias (relative to the grid). To get maximum gain the cathode resistor is bypassed. value of the capacitor should be small compared to the cathode resistor say at 50 Hz.

[@DavidTipton101]

Yes, thanks Fred 👍🙂

[@aussiedazvk4djh889]

Couldn't hear KQ. Good fix Dave. 👍🍻

[@DavidTipton101]

It's an ad station now with a bit of sport in there. Thanks Aussie Daz 🙂