[QuadList] Rebuilding RCA TR-600s

Tue Sep 8 14:48:06 CDT 2009

I think we went over this a couple of months ago.  My experience was that replacing that huge "oil can" capacitor to the power supply made a huge difference to how stable the machine was.  That said, I'm not wild about the TR-600's native TBC.  Probably fine with a nice studio tape, but it could be hell outputting an already dicey recording to something like Digi Beta which expects a clean signal.  We had mostly off-air recordings and the on-board proc amp and TBC couldn't cleanup the jitter on the leading edge of sync.

Thanks for the update.  Let me know if you need documentation.

Steve Greene
Audiovisual Archivist
Nixon Presidential Library and Museum
(301) 837-1772

>>> jwalko at scenesavers.com 9/8/2009 3:24:48 PM >>>

Trevor:

These are equipped with the editor (although not sure if it is the AE600). My big fear about these machines is stability.  Once we get them set up, are they a continual nightmare to keep adjusted properly, or do they hold settings pretty well? I share your trepidation about the TR-600s*however it was a choice of getting them working or leaving them to degrade*I just couldn't see doing that. John From: quadlist-bounces at quadvideotapegroup.com [mailto:quadlist-bounces at quadvideotapegroup.com] On Behalf Of Trevor Brown
Sent: Tuesday, September 08, 2009 3:06 PM
To: 'Quad List'
Subject: Re: [QuadList] Rebuilding RCA TR-600s

 John Walko Interesting project like the rest of the list I wait for the second installmentWe do need to know if the machine is locked to external sync Chris Hill is full of good advice The issue with the color bars changing color in the regen mode tells me that the machine is not gen-locking to the incoming black burst in that mode.  A way to tell this is to trigger your scope from the outside house burst and look at the output of the machine.  If the two signals are moving, then you are not locked A quicker way is to put external sync on the picture monitor and select itYou will see then if it is locked and it will help you tell if the if the H phase is working (Horizontal phase is not working at this point (knob turns, but it doesn't do anything). Love RCA machines hate the TR600 they were a problem from new, particularly if equipped with the AE600 editor Trevor  From: quadlist-bounces at quadvideotapegroup.com [mailto:quadlist-bounces at quadvideotapegroup.com] On Behalf Of John Walko
Sent: 08 September 2009 16:47
To: 'Quad List'
Cc: 'Jim Bird'
Subject: [QuadList] Rebuilding RCA TR-600s

 Dear Quadlist: Oh what fun it has been. It has been awhile since I've updated anyone here about our rebuilding the RCA TR-600 machines we have.  It is taking a while because we can not devote full time to this project.  But it is interesting and I am learning a lot about the operation of these machines. These systems started out in pretty rough condition.  I swear when we cleaned them, we got pounds of dust, dirt, tape trimmings and other junk out of the machine (ok*maybe pounds is exaggerating a bit*but it was a lot).  
We are almost at the point of having one of the machines up and running (yesterday was quite frustrating*more in a moment).  We picked what we felt was the better of the two whole machines (we have a third for parts).  This one had lower hours compared to the other machine and it would at least power up (including the head wheel and capstan) and would pull tape.  We were not able (at first) to get any true video signal, as it just wasn't locking up.  After pulling all the boards, cleaning all the contacts and reseating everything, we were at least able to see video, although color wasn't locking (in other words, even color videos played in B&W).  We checked power supplies and looked for any obvious things (broken wires, burned caps/resistors/boards, etc).  After a thorough cleaning, we started fine tuning the machine. Last week, we started going through the alignment procedure.  Wow*what a lot of adjustments.  A lot different than today's machines.  I'm only acting as the assistant here (ok*really a go-fer*but what the heck*I'm learning).  Our engineer has a better idea of what is going on with the machines, so some of my explanations may seem a bit light, technically. First step was alignment and EQ.  We got this looking pretty good.  What we found is that many of the adjustments were close, but a couple were off by quite a bit.  After going through the alignment, we made the TBC adjustments*color is looking better at this point, but still getting banding and drop outs in the video.  Horizontal phase is not working at this point (knob turns, but it doesn't do anything). After TBC adjustments, we went through the drop out compensator and got it adjusted properly.  At this point, the video is looking really good*actually surprisingly so.  Everything seems to be working properly.  Horizontal phase is now working. Now keep in mind that the whole time we are doing this, we are doing so with the back off the machine, because we are looking at adjustments on the front of the machine (cards in the nest) and looking at wiring on the back of the machine to make sure everything is connected as it should be.  At this point (yesterday about lunch time), we are feeling pretty good.  Good enough to button up the back to make sure the cooling works on the machines as it is designed to.  So, we put everything back together (all the panels and guards) and roll the machine back into its place.   Once this is done, we want to just try one last test.  I load up a tape, which turns out to be B&W.  It looks pretty good (no burst, because it is B&W), but it still looks good.  So we decide to put up the color tape we were working with and it looks like absolute garbage*what the heck???  The output video looked really bad when playing a color tape*lots of banding*video taking a long time to lock up (we had it locking up in about 1 second*now it was back to several seconds*probably 5-10 seconds), horizontal phase is no longer working, etc.  This is the same exact tape we saw play great ½ hour ago. Here is the situation.  We were not able to see output video by using the top switcher (we always were able to see demod and TBC*but not output).  We ended up changing that switch (which is just a manual switch).  In order to see output video, we physically had to route the cables to the TV monitor*but we wanted to be able to switch the video so everything could be done from in front of the machine.  I can't believe this had anything to do with the output video going from good to bad*since this is only a manual switch*but who knows.  Talk about frustrating*here we are, seeing really good looking video, thinking we are ready to go, only to have a setback like this. So here is our present situation.  We worked on it a little more yesterday.  We found that some of the boards in the "C" row might not have been seated completely.  We got it to the point where we are able to get video to lock up, but there is still a significant delay with the video output (the video is shifted to the right side of the TV monitor screen and we can't seem to adjust this at this point).  Our next step will be to go through the TBC adjustment (alignment) again. But at least we got to see the machine make really nice pictures for a little while (so we know it can)* There are a couple of things that are strange*when looking at demod and TBC video on an oscilloscope, we see one synch and one burst signal*but when looking at video output, we see two*and one is in the wrong place (I can't remember if we had the system in regen or house mode when seeing this*I think maybe in regen).  Note that we are feeding a black burst signal into the machine from an external generator.  This seems to be a timing issue, but I would be interested in hearing input from others on the Quad list if they've experienced anything like this in the past.  Alignment may solve this problem*but if anyone has any thoughts or ideas, I'd appreciate them.  Another, possible related issue is that if we feed bars to the machine and it is in regen mode, the video signal drifts (as seen on both the TV monitor and waveform) and the video is in B&W.  If we switch to house mode, this clears up immediately (color bars are now in color and rock steady*note color bars are from a synch/color bar generator*not an outside tape source).  The color bar generator is genlocked to the black burst generator feeding the machine.  Terminations are correct (we checked).  Strange* Another is the tension on the reels*we are playing a ½ hour tape and it seems as if the mass of the reel is too much for the system to overcome (we have to continually adjust the tension to compensate for this).  I have spare reel motors, but don't want to get into replacing these unless we absolutely have to.  We have not put a spring scale on the reel motors yet*that will be our next step.  Along with the tension problem, we have a buzzing (intermittent) that appears to be from one of the solenoids on one of the reel motors (supply reel).  This comes and goes*not sure if it is related to the tension problem or not. Once we get the first system working, on to the second system.  We're close on the first system*we'll keep you posted on progress. A couple of things learned*1.       A magnifying glass would be a great help when locating test points.  Fortunately, we have a second set of boards we can look at to help with this.2.       A short tweaker is a must (you just can't get at some of the adjustments with a long one).3.       When 2" video looks good, it looks really good, but it can go bad in a hurry.4.       I have a new-found respect for the engineers who kept these things running.5.       A second extender card can make your life a lot easier.6.       A short chair is a necessity*knee pads would be nice (ok*just kidding)7.       Supply reels and take up reels of different sizes cause problems.8.       Thank goodness for manuals*even if they aren't that well written.  You couldn't do this without them.  More pictures would be nice (of the oscilloscope, demonstrating what the signal is supposed to look like*just for confirmation).  Thanks; John WalkoMedia Archive ManagerScene Saverswww.scenesavers.com800-978-3445

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