Monday, May 28, 2012

It's been a while since I've pounced on an impulse buy, being that I'm essentially hovering in a state of critical mass I've pretty much stopped frequenting the places I run across this sort of thing. That said, I needed 100 feet of ethernet cable, so I made the trip to Next Step.

While I was there, I couldn't resist perusing the piles..

I struck out on the ethernet cable, but wound up scoring a heavy 2U modular video rack processor by Datatek. In poking about the internet I find reference to it being a D701 system, but no where on the device is a badge confirming this, and since eBay sellers are not the end all of cold hard fact I'll leave it somewhat open. Someone has marked KEVU 34 on the underside, call signs date to 1991-1997. I think I may have watched afternoon cartoons through this thing.

Anyway, let's have a closer peek at these modules. Left bank contains, top to bottom, left to right: D706 Leading Correction Generator, D709 Trailing Axis Corrector, D702 System Input & Power Supply, D703 Transmitter Delay Corrector. Right bank: D707 Trailing Correction Generator 1, D708 Trailing Correction Generator 2, D704 Receiver Delay Corrector, D705 Video Low Pass Filter.

D706. All the correction generators read similar to a graphic EQ, with a time based delay as opposed to a frequency. Each time base is variable on a +/- scale adjusted by a pot as opposed to steps of a switch. Without looking at this thing on a scope or finding operation manuals I can only speculate what function this serves. I'm guessing video sync alignment.

Gut shot of the D706 reveals a nice early potted integrated circuit. We're peeking into roughly 1974 here near as I can figure it.

D709. The trailing axis corrector strikes me as the module with the most potential. Perhaps it is the generous front panel patching. Perhaps it is the word "AXIS". I don't know, in skimming over the vast array of elements that comprise an NTSC analog signal, it could sink into numerous slots.

D709 guts. Fully discrete topology.

D702. Power section, with gain control! The power switch to the left is clearly missing the lamp cap, though it seems to actuate just fine. The bypass lit plunger was very loose and required a bit of tightening.

Not much more to say here, D702 gut shot. Does appear to be of more recent manufacture, but I neglected to pull date codes from it to compare.


D703 really doesn't appear to support anything other than set & forget operation.

D707. The trailing correction generators look similar in function to D706. D708 is also similar, but where D707 has +120, +240, +360, +480, +600 & +720, D708 carries on into +840, +960, +1080, +1200, +1320 & +1440/SPL.

Hey, this looks familiar. D708 is similar.

D704. Another set and forget module.

I really like the wandering line of the ground plane to unpopulated fiberglass. I'm also impressed by the flying wire jumper geometry.

Because no post would be complete without some borderline photography, here's the D705. Another set & forget (I think calibrate is the preferred nomenclature) though honestly this is one function I'd rather have hands on with.

33 adjustments does seem a bit much, how's about one big knob?

Here's a shot of the module back plane, relay bank & power supply. Foreground is the I/O. Speaking of big knobs, there's another that may do better on the front of this unit. Since my video processing is starting to populate my rightmost open rack I'll overlook the nuisance factor.

See, I remain fascinated with video synthesis and a device such as this seems a good "block" to have on hand. If it turns out it does nothing interesting I will have a short module frame enclosure for a future build.

Tropical fish capacitors! Tone zombies friend. These look dessicated, and to some extent falling apart. I'll file that into the "look for" list in the event of magic smoke, I really don't want to mess with any potential mojo prior to discovery. Speaking of mojo, I need some more nondescript milky white through hole parts on hand.

Fast forward 20 years and this assembler will be circuit bending Speak & Spells.

Pretty cryptic in terms of a part number. Not that I think I'd have a lot of luck finding a replacement even if I did know what I was looking for.

Clean heat sink & oxidized legs; oxidized heat sink & clean legs. What gives?

The AC mains fuse housing (5A!) was also very loose in the chassis, and the W/F Correction switch on the rear panel is in need of replacement. I'm hoping these are signs of simple nuisance/post decommission storage type failures as opposed to catastrophic BBQ. Remains to be seen, may need to freshen up those relay contacts.


pearshapedhuman said...

You know, I think that has been in there a very long time. That (or something similar) was on the shelf for over a hundred bucks. I couldn't help wondering what the hell they were thinking. Glad to see that they regained their sanity (cause I know you didn't spend no C-note!) and it found a good home!

crochambeau said...

I guess I don't get out that much anymore. I offered them $20 for it, they accepted it. Guess it had hung out for too long or the planets aligned or whatnot.

crochambeau said...

Datatek Update: The rear mounted W/F Corr - bypass switch had failed. Replaced switch and the unit does a fine job subtly distorting video, which is all I have asked of it so far.