Sorry. I wasn't clear. The bandwidth is perfectly flat to 1MHz, the 3dB bandwidth is about 5MHz, so you should be just fine.

-Matthew

Now why didn't I think of that? For that price, I'll buy a few dozen Thanks for the tip!

It will be a while before I get to this though - I have about 30 tapes to copy first. I have to say I'm somewhat amazed that these tapes, 30 to 40 years old, still play just fine.

Oh OK, now I get it. Um, yes, I'd say 5 MHz. ought to do quite nicely

The parts and the boards are ordered and I will have them by next week. Then we will see if the simulation lied or not.

If it is OK, I will ship the four new FF-10's and the video amps together, saving on shipping, but that will mean that they won't go out until next week.

-Matthew

Sure - there's no hurry. Next week is fine. And if you're serious about wanting a VT-100, send me a PM and we can work a deal.

I'm glad to find this thread.I got two of the VT-110 B&W machines. One with the monitor.TV RF modulator.Plus a camera which is in bad shape .I got to dig them out and check them out.

Nice to hear I'm not the only one with one of these. The VT-110 is essentially identical to the VT-100 with a few additional features, like the ability to record direct video, not just from the camera. The first thing you will find is that all the idler tires in the transport will have turned to goo and need to be replaced. And the two belts will be rotted away and also need replacing. Oddly enough, the capstan and sub-capstan pinch rollers will most likely be OK.

After that, you can expect trouble from the LM-1 IC's on the video board and the FF-10's on the servo board.

And that all assumes your video heads are OK. No point going any further if they're cracked, worn out, or like one machine I got stuck with, already missing entirely. Good luck!

Thanks for the info Michele .When I spotted this thread .I jumped and said Wow.I got to dig them out and start looking at them.It's been awhile since I looked at them.I can't recall the condition of the heads and the rubber in them.I got to pull out my magnifind glass and look at the heads and see if they are still intact .Yes I'm glad to see that others have the same equipment that I collected over the years. Now we can share info and tips on getting these gems up and running.I got to look for better copy of the schematics then the incomplete horrible schematics that I got online years ago.Ok what grade reel to reel tape will work on these if I get that far to try them.Will I got two to play with .I will give you updates as I check them out.

The main issue with the heads is getting them adjusted so they protrude equally. Was done
with a stereo microscope at the Central Electronics shop in Vancouver BC in the day.

Street vibrations (trolley busses) made it difficult though.

Thankfully VCRs had replacement head/drum sets.

Do not, I repeat DO NOT run audio tape (of any quality) through the Akai 1/4" VTR's. Ever. Period. While it supposedly will produce an image, it will also wear out your video heads incredibly fast. You might as well just scrub them with sandpaper. Akai sold special 1/4" video tape for these that was like $20 for a 1200' reel (and this was back in 1970!). It has the shiny side in to reduce head wear.

And even with that, I never got more than 200 hours on a set of heads, contrary to Akai's rosy specs of 2,000 hours. If you run audio tape through them, you'll be lucky to get 20 hours starting from new. And these heads are absolutely impossible to find anywhere anymore.

Most of the machines up on Ebay have worn out heads - probably for this reason. If you're lucky enough to have one with heads that still work, do yourself a favor and track down some 1/4" video tape. In addition to Akai, this tape was also produced by Scotch and Irish. The tape doesn't come up very often on Ebay, but it can be found - unlike the heads.

Am I the only one not seeing any photos?

"Am I the only one not seeing any photos?"

What - recently or at all? The last photo I see in this thread was my post on May 14th, where I included a shot of the LM-1 IC. There aren't any photos on the current page.

Thanks for the warning Michele .I'm surprised its not a similar tape grade as VHS/Betamax which is like crome tape grade in audio.like you said its a special tape grade probably lubricated with head antiwear ingredient .If I get that far with the machines .In the meantime .I will try to look for some tapes.I just now to see if they fire up.I will post photos later when I get time to take them and upload them.As for the camera .I think its a lost due to the cracked PC board which I try again at it.The case for the camera is missing .that how I received it .from a friend.

From the very first page of this post back in March when it started:
QUOTE by Michele: "Well, it's time to begin my latest project - an Akai VT-100 1/4" open reel video tape recorder from 1974. Here's what we're dealing with:
There is a block where a photo should be, no photo shows up.
I was just wondering why thats all.

Hmm - sure enough. Well for completeness sake I guess, here's that photo again:



Here you can see the takeup reel drive belt off its pulley. The fast wind belt is missing. This was right at the beginning of this project. In the upper left is the video board. You can see that orange IC with the number "2" on it. That's the LM-1 I replaced last week.

Well, here it is. The first reproduction LM-1 is done and working. Amazingly, this thing worked on the first try. It has a gain of approximately 20dB into a high impedance load and provides a 3dB frequency of 4.2 MHz, also into a high impedance load. I will keep the first one (pictured) as I always keep the first serial number of a new product, but I have two more ready to ship to Michele. I hope they work in the VT-100!



-Matthew

Ha! That is just so cool. I'm still just totally amazed at the way you put these things together. That's really awesome. Thanks!

So far, my now-working machine is holding up, although I've run into a problem trying to copy my half-hour tapes. These are slipping on the pinch roller because they're only half-mil. I'm going to try cleaning the roller and the capstan. If that doesn't work, I'll have to go into the pinch roller tensioning adjustments in the manual.

The other problem I'm finding is that every tape seems to have been recorded with a slightly different setup, so I have to constantly readjust the tape guides to get them to play. What a pain.

That is a great piece of engineering you have done.

Don't mean to hijack this...but I have a complete Akai VT-100 kit with VCR, camera, monitor and RF modulator in a case. Reasonable offers will be considered. I have pictures as well.

What shape are the video heads in?