Ikegami 2/3” VTR

[Yellowtriumph]

Ikegami have a long and honourable history in broadcast TV: https://en.wikipedia.org/wiki/Ikegami_Tsushinki At the Broadcast Engineering Museum we like their colour monitors which tend to "just work". I have a 1960s Ikegami 9" monochrome monitor above my bench. Picture quality is mediocre but it's very useful. I lock it to my lab SPG and feed it with the Y output of my 'scope. Incredibly useful for tracing problems in both analogue and digital video systems.

The ACR25 and TC100 were incompatible cassette formats though the recordings on the tape were standard quadruplex. Both machines were astonishingly complex and expensive. I wonder if any survive in anything like working order.

As to the ACR/TCR I have suspicion (that I can't back up) that there may be one or two surviving around the world. I used both during my career, the TCR came first from RCA and was quite a breakthrough as I understand it. It was very mechanical in its operation and the mechanics were often compared to a 'tractor'. Lots of cogs, belts and moving arms to get the right cartridge into position before a pair of arms pulled the tape out of the cartridge into the head assembly. You certainly kept your arms out the back of the machine when it was in full flow - and there were two decks! The playback unit was complete in itself and from memory the electronics was DTL. The output of this TCR 'part' fed a downstream signal processor called an SPU which dealt with the finesse of signal processing, it could be a dedicated unit for the TCR or it could be shared with a conventional VTR (TR70 was usual) - RCA were always looking at ways to reduce costs for end purchasers which were mainly 'mom and pop' small tv stations throughout the US.

Ampex brought out the ACR after the TCR. Again from memory it was built around TTL and there were no microcomputers or anything like that. The mechanical side of it was largely vacuum controlled - a cassette would be put into the correction position and the tape sucked out of it and loaded up. Ampex developed a new headwheel panel for it and its big brother the AVR1 VTR which involved the guide mechanism retracting so that the tape being loaded would fly past it without interference and then the guide would come back into position once the tape was loaded into situ. Used a vacuum capstan roller (not a pinch wheel and rubber roller like the RCA machine). Could also play back tapes that had no control track. I believe the first two in the UK were bought by Southern TV in the early 70's and they were still going in the late 80's. Both the ACR and TCR usual carousel arrangements to store and move the cassettes around and into position.

You may have subtly noticed my terminalogy. ACR = Ampex Cassette Recorder. TCR = Television Cartridge Recorder. Patents probably. As you say both used the conventional quad format but other than that completely different and incompatible. The machines had to know where the tape was mechanically inside the cassette/cartridge as it could be anywhere - if it didn't know the machine could accidentally spin the tape completely off the spools inside the holders. Again from memory I think RCA used reflective foil stuck on the side of the magnetic tape at either end, Ampex used holes punched in the side of the tape. Holes being cheaper than silver foil. Bit simplified but I hope you get the gist. One or two videos on youtube showing both machines in action - both impressive.

I still have an RCA cartridge in my study, and one of those special Ampex XX head wheel panels on the floor as a door stop! Ampex must have spent an absolute fortune developing that very complicated headwheel panel, RCA achieved the same result with a small piece of bent metal, probably cost them no more than 10p! Wish I could find some pictures to illustrate.