EEVblog #289-1 - VCR Teardown & Handifax Followup

An impromptu VCR teardown when Dave has to open it up anyway to extract the scrunched Handifax 1000 video tape!

[sdp]

VCR's are great sources of motors, the older the better as they have much heftier motors.

[Eyetrauma]

"There was a Shark Tale DVD stuck in it. Presumably that's why they threw it out."

That'd be my reaction to Shark Tale as well.

[Trevs-Shed]

Ah. Now we are talking my language.
Still get to repair the odd VCR.
The changes from the 80s to now is huge.
Used to be big business. The selling/repairing/renting of them.

Those were the days.

[Dibblah]

Very cool. That looks like a play-only VCR - On record ones, there's also an erase head that's separate from the audio / video heads. And the likelyhood is the helical head only has 4 heads (if not two!), the others are audio. Completely agree that older ones were far more complex both in electronics and mechanics - Partially, this is because motors and control circuitry is now cheaper than cogs and gears. Great to see a "new" one - Thanks!

[Skyfox]

Not sure if anyone's commented on this before.  A "6 head" VCR is actually nothing more than a 4 head VCR, but they decided to include the two audio heads for the left and right audio channels to give the marketing illusion that it's better quality than a standard 4 head VCR.

[Mulletsrokkify]

2:51 is the back-tension band which applies tension to the take up spool to give some tension/dampening to the tape. 9:29 is the combined mono audio and servo head, which picks up the servo pulses on the tape to synchronise the playback head and capstan motors. I did my electronics repair apprenticeship repairing junk like this! The later VCR's became extremely refined mechanically compared with the old top loaders. Ahh, the old days when consumer electronics were repairable....

[Menimitz]

All the hours I spent watching vhs tapes I was never aware that's how they worked. Thanks!

[toshineon]

Interesting stuff for sure. I've had a small fascination with analog media such as VHS tapes lately. Most people I know watch all their movies on Netflix, but for me, watching a movie means putting a VHS tape in the drive, hit rewind, and go get soda and popcorn while you wait.

[hughturner]

Little late to the party, but if anyone hasn't said it, the reason the head is at an angle is it allows them to fit more data on the tape. instead of running the heads perpendicular to the tape only allowing about 1" of tape to hold a "stream" of data, running it at an angle lets them get 4-5" of data per swipe of the heads along the tape, so you can double or more the available data per rotation of the head.

Shallower angles allowed for greater picture and audio clarity (more information) and also prevented cassette producers from having to go to larger spools keeping the cartridges relatively compact in the face of higher definition movies, and longer films.

[AAAZA]

PAL VCR's revs at 1500 RPM, and NTSC at ~1800 RPM I think

[williefleete]

the tape backing up a bit was for the leader tape detector. the belt looking thing on the supply reel is a clutch, it regulates the speed that the take up reel pulls. also the audio head has the control signals which will be the line/frame sync pulses and how modern VCR's figure out the tape run time

[thecrikster]

My Granddad (sadly no longer with us) spent his life working as a TV and VCR service tech. He never got to see the solid state storage technology we have today. I always wonder what he would have made of that.

[gamccoy]

The head is canted to get a helical pattern. The data is stored in vertical strips on the tape to maximize the data storage and prevent having to have the tape move a several feet per second to get the same amount of bandwidth.

[FrozenHaxor]

Wow they simplified the VCRs so much since then.... They used to have alot more complicated mechanics and PCBs all over the place, sometimes even 4 of them facing towards each other forming a cube!

[whiskeyify]

I used to work in a repair shop and the old vcr's had a lot of metal parts...but the new ones are mostly plastic. We often used super glue to fix the broken plastic parts. I have a really old RCA that still works, they were built to last a long time.

[KozmykJ]

IIRC The 6 heads on a domestic VHS drum were 4 for the video, and two for the PCM/Hi-Fi sound.
The 4 video heads were for better quality when using ELP (Extra Long Play).
There were variations though depending on whether the machine had editing functions.
For an edit capable machine there would be 2 video heads, 2 PCM audio and 2 flying erase heads.
The stationary head performed 3 functions. Sync track, Lo-Fi audio (mono or stereo) and erase.
There were even 8 head machines. Don't ask ;^)

[excavatoree]

Ah, memories. My first job was a VCR repair person. That was cough, cough years ago!

[dhpbear]

9:22 - Starts to play automatically if write-protect tab is removed.

[dhpbear]

8:00 - That horrid noise is created by 1/4" diameter rollers inside of the cassette (plastic-on-plastic)

[doodh_jalebi]

Just saw your first video Dave!
"One small step into video blogging, a large leap for learners to learn"