Panasonic PV4780 VCR Dead will it work?

[@thefakemaker]

My dad is really liking your videos. It’s great to see someone fixing stuff but sad we live in a world where fixing stuff isn’t the norm anymore.

[@topgrain]

Mid 1980's VCR's are some beautifully intricate machines. That bottom view of of the tape-handling mechanism at 03:33 is awesome.

[@gabrieleorioli1760]

Wow, that's quite a cool machine. To be honest, the "special effects" are what amazes me the most in VCRs. Slow motion, perfect pause, variable speed and stuff...

[@12voltvids]

I still remember one of the sales guys at the shop selling a customer on one of these machines telling him how good his porn would look in "double fine slo-mo". That's ok he also told another customer to bend over so he could shove a CD player up his ass. (Yes he knew the guy) we got a good laugh. One time he made a wise crack and a woman that he didn't know was in the store popped her head out of the sound room and said "pardon". He turned beat red and we dam near pissed ourself in the back we were laughing so hard. Another customer was picking up a tape that we had copies. She enquired "how long is it" referring to the running time. Without hesitation he responded 7 inches. In this case she turned beat red and walked out. We roared over that one too. Next day she returned and said she wasn't offended and was laughing the rest of the day to his response. His response to that... Want to find out. Today you could never get away with that behaviour. Too many snowflakes today.

[@jeffadams5510]

@@12voltvids Only 7 inches eh?-LMBO!!!!!!!!!!

[@stephendevore3902]

Thanks for explaining the head and the recording mode movement. I knew the basic operation. Back in 1990s information was limited. How everything worked and how precise everything had to be. I had thought at the time you more control in general. Everything with speed modes was more complex in operation. Now I know in detail the process. Unless you were in the environment you many times were guessing and guessing wrong in my case.Not having Internet just book and basic diagram to work from.You have equipment I wish I had then.Good Video

[@Oldgamingfart]

Interesting to see an upmarket machine with both digital features and Hi-Fi, as so often it was either one or the other!

[@MrDsmen]

Havent seen the video yet but I already have to say that is one cool looking vcr ! Growing up in 00's I dont even remember seeing a single one looking this nice, thats for sure

[@12voltvids]

This was one of the better ones.

[@waltschannel7465]

Gotta love the construction details. Aluminum die cast chassis, wires neatly bundled. No soldered in ribbon cables. Less than 8 million obscure screws to remove. OK, agree, the P/S is a bit painful to remove.

[@12voltvids]

It has those composite modules that gave so much trouble though.

[@eman59461]

Great video. Reminded me of when i used to repair VCR back in the 90s. Ran in to one of these that actually blew up.

[@12voltvids]

I saw a few that blew up. Every chip and transistor had a hole blown in it.

[@crashbandicoot4everr]

​@@12voltvids Do you happen to remember which models suffered from this?

[@12voltvids]

@@crashbandicoot4everr Early models. Don't remember any model numbers. It affected all the first generation with switching power supply. They didn't have a crowbar on the secondary side. How these power supplies work was by changing the frequency of the oscillator to move the transformer closer to or away from residence they all worked on a 50/50 duty cycle. Early designs operated below resonant frequency and as the frequency increased the transformer got closer to resonant as the frequency decreased the transformer moved away from resonant frequency these transformers the efficiency changes as you move away from the resonant frequency. If the voltage is low the oscillator increases in frequency and moves the transformer closer to its resonant frequency which increases the efficiency and thus increases the voltage on the secondary. To decrease the voltage the frequency decreases. The problem was when one of the small oscillator capacitors went open the frequency would start to increase on its own and even though the optic coupler was in full conduction screaming voltage too high decrease frequency because the oscillator cap was bad frequency kept rising that's bringing the transformer closer to his resonant frequency. Ultimately because there was no crowbar across the secondary the voltage would rise to the point where every semiconductor would blow up. The interim fix was to throw a 5 volt and 12 volt zener diode across the rail so that the voltage went too high the diode was short and that would blow the power supply. They then change the design to move the oscillator above the resonant frequency of the transformer in the power supply. The primary cap would still fail and would still cause the frequency to rise but because of the redesign the rising frequency would move the transformer away from its resonant frequency and thus cause the voltage to drop. I don't remember the models that were affected it was all of them until the changeover took place. Even the ugly ones with the circuit board that you had to flip up over the top that covered the heads, the garbage mechanism that used to solenoid under the cassette basket to operate the planetary gear set where the caps and motor controlled the threading and unthreading as well as the front loader. Even that one used that crappy design and the two diodes to protect or on the main board at the edge of the board and they would short.

[@eman59461]

@@12voltvids Thats so Crazy. If i looked a little further i would have seen it most likely. Thanks for sharing.

[@crashbandicoot4everr]

​@@12voltvids Interesting that Panasonic didn't put zener diodes for protection early on. My 1981 Sanyo Betamax does have zener diodes across the 12V and 15V rails that go short in case of overvoltage. That power supply is based on a couple of TL494CN chips.

[@Barbarapape]

Panasonic VCR's of this era we some of the best they ever made, the later decks were not as robust. Switching power supplies cook capacitors, i always replace them all with good quality 105 deg ones to save a repair coming back. Seems a long time ago since i was repairing these models, or is it me getting old!

[@crashbandicoot4everr]

The G decks are a nightmare compared to these.

[@Barbarapape]

@@crashbandicoot4everr I know, i have had to try and fix a few of them! These older decks with some tlc will last for years, the later models are best avoided.

[@waltchan]

@@crashbandicoot4everr That's the newer 1988 Panasonic PV-S4880 S-VHS.

[@waltchan]

@@Barbarapape 1989-1990 Panasonic PV-S4990 is the best one to avoid. Over 100 surface-mount capacitors can go bad today.

[@Barbarapape]

@@waltchan Surface mount capacitors dry out like most do, and due to their small size they fail even sooner. I was working for the MOD and sent on a surface mount training course, and that was when you could see them, today they are specs on overcrowded pcb's, if you try to remove one with hot air you end up replacing a lot more. Some products are not designed to be repaired.🤔

[@waltchan]

The Panasonic PV-4780 was the highest-end and top-of-the line VHS VCR model from Panasonic for 1987 year, retailed for over $1,000 new. It's the last Panasonic VCR with the traditional 2-belt die-cast design. The next year one was 1988 PV-S4880 S-VHS with G-chassis mechanism and came with only 1 power supply, but it was less-reliable. The 1989 one was PV-S4990 S-VHS that uses AG-1960 mechanism, but it has over 100 surface-mount caps and least-reliable.

[@12voltvids]

Yup. 4780 was the best that Panasonic made.

[@waltchan]

@@12voltvids I think the 1985 Canon VR-HF600 (Panasonic AG-1800 clone) that you uploaded a video before has the slighter-edge than Panasonic PV-4780 for reliability. No power supply issue, since it has a linear power transformer. And you don't need to worry about digital effects board failing too.

[@12voltvids]

@@waltchan it has rubber tires that wear out though.

[@spatsbear]

Just realized, that is Alf's VCR! Season's 3 & 4 intro: kzbin.info/www/bejne/iqjShZdsiN-AsLM

[@12voltvids]

Looks like it.

[@keepingitreal71]

Love watching your videos... I am not like my dad was... He was a tech nerd.... Would love to see you fix old radios made for kids.. like a Big Bird Radio.. or a Snoopy Radio....

[@lox_5017]

What does it mean by switching power supply? What is switching in the power supply board? How is a linear power supply differ?

[@amatorev]

Nice devices, I also ordered an old Sony CCD V100 Pro (1986) video 8 camcorder from eBay Germany the owner told me it works perfectly I hope it has good capacitors and not bad as in your video haha

[@ThejasonJaw5442]

Everybody needs to have a pair of electricians l scissor I use them on all my jobs they are amazing

[@PhillipRemaker]

The Dick Smith ESR meter does a good job reading ESR in-situ without removing the cap!

[@12voltvids]

Yep

[@sunilsoma456]

Very good work Sir.Thanks ji

[@Vintaginside]

Building quality looks superb. I like the feature of unthreading the tape: less friction and less wear, as some Beta decks (mostly Sanyo and some random Sony).

[@12voltvids]

Beta kept tape threaded. A few sanyo models unloaded the tape but I had a sanyo that kept the tape threaded. This was a good model. One of the most reliable that Panasonic ever made. As can be seen after changing those caps in the power supply it plays the tape like a champ. The big reason for keeping the tape loaded of course was for a quick operation and for a linear tape counter sub machines such as panasonics industrial decks used a half load with a separate guide that pulls the tape out to the control head so that the control pulses could be read for the linear counter. But you're right VHS text that unthread the tape do have less wear and tear on the heads during rewind and fast forward. This problem however was mostly solved with the redesign of the tape path and moving the caps and in pinch roller back further into the chassis to reduce the sharp angles that the m loading system created. Back when Sony was the main developer of home video along with JVC and Panasonic the main reason Sony designed the beta system like they did was to avoid the sharp angles and made it more like the three quarter inch machine. Of course that all went out the window when they came out with their horrible 7-Eleven chassis which basically had the tape doing a 180 at one side of the drum with those guideposts or guide pins that popped up from under the chassis.

[@sunspot42]

@@12voltvids Yeah Beta in theory put less stress on the tape, since you wouldn’t be loading and unloading it as much, but more stress on the heads in particular since the tape was always being drug over them, even in fast forward and rewind. The VHS loading path was also more angular, which stressed the tape. In practice tho I’m not sure it made a huge difference, in part because tape became more robust and also because VHS VCRs became more refined. I had a Sanyo 7250 SuperBeta HiFi deck that unthreaded the tape when changing modes if memory serves, just like a VHS. It was the best Beta deck Sanyo ever made and in my opinion was better than all but a handful of Sony decks.

[@12voltvids]

@@sunspot42 the original 3 piece drum Sony put virtually no wear on the tape. The center piece that spins had air channels that sucked a thin layer of air that cushioned the tape keeping it a few microns off the drum.

[@sunspot42]

@@12voltvids Yeah that design really babies the tape. They got that design from their U-matic decks, didn’t they? Or am I misremembering that? Why did Sony abandon it? Just too costly? Seemed like a really good idea and I’m surprised it wasn’t adopted by VHS, especially with their plethora of heads.

[@12voltvids]

@@sunspot42 the original beta had a 3 piece drum. Umatic drum had rotating too like 8mm and 8mm. The 3 piece drum was good but required specialized equipment to change (micrometer to do escintricity adjustment and dihedhral shims to set the azimuth on heads) this requires specialized training and if you didn't work for Sony you didn't generally get it). The mechanism was physically large. The last series to use it was the 5000 series. 710 chassis. With 711 they went to the slimline chassis to make things more ore compact to make s smaller portable.

[@wx4newengland]

I have a PV 1545, looks similar. Was a great deck for the first 12 years, but after that- it became troublesome

[@crashbandicoot4everr]

7:00 14V rail measuring 18.6V with two 18V-rated caps across it. Well, looks like this is one of those Panasonics that can really blow up...

[@jr-pl9kj]

if those digital circuits fail. will if affect anything? can they be removed and bypassed ??????

[@celaphingary6853]

Very well

[@kyoudaiken]

How did they get contiguous playback with the audio with this arrangement? Did they buffer the audio frames digitally?

[@12voltvids]

What do you mean?

[@kyoudaiken]

@@12voltvids There is a timing dead zone in the blanking area, isn't there? But you still would have to be able to store and playback audio in those areas where the heads do not touch the tape.

[@12voltvids]

@@kyoudaiken no actually there's not there's 100% coverage you actually can see the video switching point on VHS that occurs six lines before vertical sync, I'm beta it occurs seven lines you see it at the bottom of the picture as a slight disruption where they switch over takes place. They did it prior to vertical interval so that the disruption did not occur during the vertical interval which incidentally there are still sink pulses in that "dead" zone. St Paul says never stop horizontal sink runs continually and vertical sink occurs every 60th of a second, actually every 59.97 of a second! On beta the handoff is done at the same time as the video head is switched from one to the other, VHS occurs mid field as the VHS Hi-Fi head is 45° ahead of the video head. There is an overlap the switch takes place at the overlap. On beta Hi-Fi they used four different frequencies too frequencies for the a head too frequencies for the B head so four separate FM tuned receivers and they switched rapidly between one and the other you can with a critical ear hear it. It causes a slight wobble in the sound on both VHS Hi-Fi and beta hi-fi which is what makes me laugh when people tell me how they use their VHS Hi-Fi or beta Hi-Fi as an audio recorder and it's the best recording they've ever heard. Obviously these people are tone deaf because I can pick the warble out soon as I hear music playing off of a Hi-Fi tape I can hear it it's a horrible at about 60 HZ

[@kyoudaiken]

@@12voltvids Ah good to know! That's the weird distortion you see on digitalized videos. On TV it was outside the visible area inside the overscan area. When you digitalize you have a lot more lines visible than back then on the TV. That explains the weirdness going on at the bottom, head switch 6 lines before VSync. Makes sense! About VHS-HiFi... I think the wow and flutter of turn tables and cassette decks made them indeed tone-deaf to those artifacts. I am VERY pitch sensitive. I prefer the HiFi sound over the regular telephone mono quality but it's FAR from CD audio of course...

[@crashbandicoot4everr]

@@kyoudaiken On most old VCRs you can adjust the position of the head switching point. The adjustment is called "PG Shifter" on Panasonic machines. PG as in Pulse Generator. Really old machines have two separate PG adjustments, one for each head.

[@tyronenelson9124]

Could you not hear the infamous 'whine' that the power supply was making each time you plugged the VCR in?

[@12voltvids]

Yes. And the microphone really picked it up clearly.

[@michaelturner4457]

This video made me dig out my Yanni DVD.

[@12voltvids]

I have it on laser disk. Fantastic quality.

[@crashbandicoot4everr]

I found a picture of the remote and it does indeed have PinP, strobe and TV freeze buttons. Kinda gimmicky if you ask me...

[@12voltvids]

I figured that. I had an RCA years ago an svhs that had pip strobe multi screen freeze solarize tv freeze ect. The tv freeze was for those that were watching live TV through the tuner and wanted to freeze the picture so they could go grab a pen to write down a number or something displayed on the screen. The only cool thing was if you had say a security camera you could plug it into the video in and have your camera picture overlaid while watching TV. Covering up 1/8 of the screen.

[@reacey]

This reminds me of a machine seen in the movie home alone

[@t0nito]

That mechanism sounds exactly like my 1987 GE 9-7500!

[@KylesDigitalLab]

Panasonic probably manufactured it for GE.

[@waltchan]

@@KylesDigitalLab GE VCRs switched to Samsung, starting in 1990.

[@Jammerk40]

How come two power supplies?

[@12voltvids]

One is for the digital boards.

[@fredchatham6680]

Function switches were the weakest link in many quality VCRs.

[@NigelMontezuma]

Now Get The VSQS0575 Remote

[@Raptor50aus]

I recognize those Elna caps :( Sony used them in the Indextron tv and they all leaked.

[@thetechgenie7374]

Elna capacitors usually leak. Seen some nichicon capacitors on Sony machines fail as well, usually when power up they start to leak.

[@12voltvids]

Elna made Cappy craps!

[@Raptor50aus]

@@12voltvids yes what a shame

[@waltchan]

Panasonic didn't use Elna caps. If it has Elna caps inside, the power supply was serviced before in the past.

[@zx8401ztv]

l imagine it wasn't cheap in it's day, but fancy machines were never cheap. Never liked the idea of video tape wrapped round the drum all the time. I'm sure you will have another tinker with the panasonic when you are in the mood without stress. Dave, the trouble with you is you have repaired most devices and there isn't any meaty interesting devices to sink your teeth in to lol. Hmm vcr on toast, yummy lol.

[@12voltvids]

1000+

[@groovejet33]

You get either sent this ditritus? Or pull all this old stuff outa the deepest darkest corners of the attik, lol. I wonder its because you actually love fixing the older crap?

[@12voltvids]

I got this one at the estate clear out I was at. I do sell this old stuff off. There are a few things i will keep like the Edison record player.

[@volkerking5932]

Why you're wasting time for measure Caps old like this? This Video Recorder have all Caps defect not only a pair or so. This Video Recorder is now >30years old so change every time all caps if they are so old. Thumb up 260! Best Regards Volker from Vienna

[@12voltvids]

No, you are wrong. Only a few key caps in high frequency high current applications will fail. The rest will last for decades. Amateurs just go in and change them all because they do not understand why and how they fail and or don't have equipment to measure. Or they think that all bad caps will be bulging. This thing is worth about 20 bucks so there is no way i am going to replace more than the bare minimum. Again because only key caps will fail. I had an Amplifier a few years ago in where the owner demanded that all the caps were replaced. I did and charged accordingly. He got that amp back and brought it right back because he wasn't happy with the "new" sound. Had me pull all the new caps and put the originals back, and paid me a second time to do it. Yes they will change the sound but the fact in new caps have completely different characteristics electrically than old caps and it changed the sound on an old sansui to the point that it was bothersome to the owner. There was nothing wrong with the amp when it came in other than dirty controls but the owner had listened to internet advice and wanted all the caps done. He supplied a cap kit he bought online and didn't like it. Back in went the old caps from the late 70s. Don't ask for a link as it wasn't recorded. It was a project I took on and the owner was standing there watching me change them and because of that i didn't record it. I did make 300 however for changing them twice. The exception is with tube gear. Old wax caps go electrically leaky and will burn out other parts. They all have to go.

[@volkerking5932]

@@12voltvidsTechnical - Yes I understand that you build all Caps out and measure it - well. But what I mean is that we change in old machines like this all Caps (inside the Power supply) in case of the working time. A Cap is much cheaper then the expensive working time and TAX here in my Country Austria so there is not time to calc for the working time. The Consumer will not pay the working time so I must change all in very short time because we have a Company TAX here from about 75%. What will you charge for your work here in Austria? We also know all about MTBF@100, ESR and Ribble, Temperature and so on but we have a workingtime problem here! (We also have the experience that Nippon Chem, Panasonic and Rubicon are building Caps they live more or less for ever). This is the reason why I change all Caps in very short time. Here in Austria is no time to do that what you do in your area. I accept your work well and it is made good - if I have had a Customer they don't want to pay the expensive working time. For Example a hour of working time cost here in Austria between Euro 70,- - Euro 100,- + 20%VAT this is for my Customer now 70 + 14 (+20%)= Euro 84,- or 100 + 20(20%)= Euro 120,- You see that from the technical perspective but we must work for our money very hard because the TAX is so high. Now you have seen my perspective of repairing things like this. But if you change only a view Caps so like you it is a high risk that exact the machine come back to a warranty repair with the same failure (and Amateurs make this failure) and this is for only a cheap Part like a Cap not arguable from the economical standpoint! Best Regards Volker from Vienna PS: believe or not in Austria if you earn Euro 1000,- in your cash register so you must pay... earn cash 1000,- /120(20% including) = 166,66(20% VAT) => 833,33 from this your Company must pay -25% Körperschaftssteuer (Communal TAX each month) = 208,33 => 625 and then if you pay out of the company you must pay the Social Insurance and the 27,5% Einkommenssteuer (Income TAX) this is arround ~50% 625/2= Euro 312,50 netto! But then if you go to a other Store and buy some thing so you must pay the VAX 20% => 312,50 /6= -52 => 260,42 this is your power of the money after all the TAX and now you know why we can't work like you.

[@12voltvids]

@@volkerking5932 The thing is here you see someone might pay for a VCR 20 - 30 to repair. On a piece of vintage audio gear perhaps as high as 100. Same goes for camcorders. 25 years ago it was the same. If a VCR ran more than about 60 to repair they were junking it. I just sold two VCRs in the past week I got 20 bucks each for them. So the question is why would I put 10 capacitors at a dollar a piece into a device that I'm going to get $20 for when I can put three capacitors in to fix it. People here will not pay that much to repair equipment. Not too many people come up to me and say rebuild it I'll spend $200. If someone did I would just change all of them in the power supply but they don't. You also need to understand that most of the stuff that I'm fixing is stuff that has been donated to me and I am fixing it only to dispose of. So I'm not about to put any more time or effort or cost into it that I absolutely have to. As long as it's working so that I can sell it off cheap then I'm happy. You might not agree with this but look at economics as I explained earlier why would I spend more on parts that I'm going to get for the unit when I sell it and that's the problem. Unless it say particularly high-end device that someone is going to pay a ton of money for it's just not worth it. Once again I will say that changing every cap is the amateur thing to do because as I've stated before not every cap will fail, only certain ones will go bad and it's always the same over and over. If you don't know what you're doing you can change them all knock yourself out if you got someone who's willing to pay to have that done all the power to you maybe things are different over there but here people won't spend a penny more that they have to in most cases and if you tell them hey you need to change all the capacitors it's going to cost $150 or 200 to do the job they will walk nine times out of 10. They come in with a preset limit in mind and will dictate to me how much they are willing to spend. In most cases it's $50 or less. At today's exchange rate that's about 34 Euro. That's all I make fixing the average tape deck or amplifier. In many cases it's less than that. And that has to include my time, parts, and any tax I have to pay to get the parts. This is why all the repair shops close their doors. The whole purpose of my KZbin channel is to teach people how to troubleshoot and replace the components that are most likely to fail in specific devices. If you want to take that advice and kick it up a notch and replacing all the capacitors you're welcome to do so but nine times out of 10 just changing the ones that I measure and show that are bad will get the unit up and running and it will run for a long time until something else breaks. When it comes to VCRs most people just want the running long enough so they can digitize their tapes that they meant to do 10 years ago but never got around to it. Once they digitize their tapes they're cleaning house and then throwing it all out.