I'd never looked into VCR's in any way what so ever until about a week ago.
I need some form of magnetic tape storage medium for something I'm working on. Since we have three VCR's, I decided a VCR would be a great place to start.
The problem is obvious, I have almost no idea how they're actually laid out.
The rotating head is the helical read / write drum, I hope. Looking down on the bay from above, the head to the left of the rotating drum is the erase head right? Just of interest, what frequency does the erase head run at?
Is the erase head writing random data to the tape or a smooth signal, to reduce noise?
What I'm not sure about is the head to the right of the read / write drum. In the videos I'm looking at, it looks almost like a seperate read write head. Is this head for the linear mono audio channel?
I know that there are probably a lot of guys here who could build me a VCR from scratch, so if you could help me out this these problems it would be great!
I need some form of magnetic tape storage medium for something I'm working on. Since we have three VCR's, I decided a VCR would be a great place to start.
The problem is obvious, I have almost no idea how they're actually laid out.
The rotating head is the helical read / write drum, I hope. Looking down on the bay from above, the head to the left of the rotating drum is the erase head right? Just of interest, what frequency does the erase head run at?
Is the erase head writing random data to the tape or a smooth signal, to reduce noise?
What I'm not sure about is the head to the right of the read / write drum. In the videos I'm looking at, it looks almost like a seperate read write head. Is this head for the linear mono audio channel?
I know that there are probably a lot of guys here who could build me a VCR from scratch, so if you could help me out this these problems it would be great!
heya eeka, the spinning head is normally only the read head, a black stationary head is normally the record head, that normally erases over anything when you record. From memory on the machines ive worked on, the black head records the audio aswell.
To find what head is for recording, bang in a tape, take the cover off and hit record, see what head is touching the tape and you know then atleast what is record.
I dont know what model you have or how manny heads u got lol , but yeh they can differ. As for the freq, not sure, wont be hard to find out though on the net.
Trev
To find what head is for recording, bang in a tape, take the cover off and hit record, see what head is touching the tape and you know then atleast what is record.
I dont know what model you have or how manny heads u got lol , but yeh they can differ. As for the freq, not sure, wont be hard to find out though on the net.
Trev
Hi Trev,
Thanks for the help. I've found out a bit more since my last post.
I discovered that the read / write heads are both in the rotating drum. But I'm not sure what it is that the tracking adjusts to line up the helical pattens. Whether it's the tape's speed, the drum's speed or the height of the heads.
I my project, I will need one head to record while the other seperate head reads the info off a bit futher down the tape. So I could really do with figuring out the tracking control! 😀
These things seem incredibly cheap considering the precision they seem to be made too. That's mass demand at work for you I guess!
Thanks for the help. I've found out a bit more since my last post.
I discovered that the read / write heads are both in the rotating drum. But I'm not sure what it is that the tracking adjusts to line up the helical pattens. Whether it's the tape's speed, the drum's speed or the height of the heads.
I my project, I will need one head to record while the other seperate head reads the info off a bit futher down the tape. So I could really do with figuring out the tracking control! 😀
These things seem incredibly cheap considering the precision they seem to be made too. That's mass demand at work for you I guess!
Heya buddy, ya ive only worked on a few so they are bound to differ.
With the tracking there are 2 white roillers with a steel screw head, they are set for the tape to track perfectly on the spinning head, they are normally what goes first in the mechanisim other then the belts. You can ajust these but they can also be a pain to get back into alignment.
The tracking control you have on the unit should be the speed of the spinning head, other then that there isnt much left at all to do with the mechanisim side of things. Worn or stretched belts is normall the problem with trcking, as belt kit is the go.
Ya i agree, but look at the price of them when they first came out lol, imo they wernt so crash hot then either compared to the later models.
You got admit though, the good old vcr arent bad, they cop alot of wear and tear before they break, they also have a lower tolerence compared to dvd players and alike before they actually arent usable.
Trev
eeka chu said:
The tracing control isn't going to help you with what you are trying to do.
The "video head drum" uses a combo read/write head setup. Both of the heads on the drum have the same signal on them all of the time. The reason for two heads is so that as one head leaves the tape the other is starting its track across the tape. This allows for continous recording at high tape to head speed. The quad head VCRs do the same thing, they just double the nimber of tracks so the two heads are recording or playing back at the same time. It works just like a cheap cassette tape deck, when you are recording there is an erase head that the tape passes over first. then it goes over the record/playback head. The only difference is that in a VCR a seperate stationary head records and plays back the audio.
If you need record and playback at the same time you will need a good quality cassette deck with seperate record and playback heads or an old reel to reel deck. Some pro video gear has the feature your looking for but is very expensive.
Later BZ
Thank you TV man,
The tracking control problem was that I would have needed two seperate read write heads for the tape to wrap around in this application. One would record, and then a delay would be produced, purposely, by the time it took for the written information to reach the read head futher down the tape. So I figured that I would need to align the tracks correctly between the two seperate heads to optimise the output; like the way any tape you rent from Blockbusters usually starts the VCR autotracking.
Anyway, your suggestion I think will be much easier to work with, a standard reel to reel cassette machine.
Do you know of anywhere that I can buy read and record heads for magnetic tape?
The tracking control problem was that I would have needed two seperate read write heads for the tape to wrap around in this application. One would record, and then a delay would be produced, purposely, by the time it took for the written information to reach the read head futher down the tape. So I figured that I would need to align the tracks correctly between the two seperate heads to optimise the output; like the way any tape you rent from Blockbusters usually starts the VCR autotracking.
Anyway, your suggestion I think will be much easier to work with, a standard reel to reel cassette machine.
Do you know of anywhere that I can buy read and record heads for magnetic tape?
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