[QuadList] Restoring an RCA TR-600

[Steve Greene]

Congratulations on your new acquisition.  
 
I assume you have a full raft of the available documentation.  I particularly recommend the spiral bound manual they issued to engineers attending the RCA technical seminars.  
 
I ran a number of these machines so I have some recommendations.  First, replace the main power capacitor (the oil can sized thing housed in its own shield hanging off the power supply).  This cap is at least thirty years old now and you can assume it is half dried out.  Be careful, it can hold enough current to toss you across the room or kill you.  On our machines, this cured much unexplained flakiness that plagued these machines and gave them a rep for unreliability.  Before I replaced it, the compressed air ran though the card cage and voltage regulator circuit during cleanup was enough to light the machine up like a Christmas tree.
 
The downside will be that you will pretty much have to run through all the basic setups afterward.  Second, replace all the nylon vacuum fittings with brass.  The nylon parts will fail.  I've seen unused spares cracked in the factory boxes.  Third, clean and replace all the air and vacuum filters.  Fourth, clean the linkages behind the headwheel panel.  Tape flakes and dust will foul them and slow the reaction time of the vacuum guide.  Hopefully you have the jig that allows you to adjust those linkages.  Fifth, clean the card edge fingers for each card (tape flakes and dust get everywhere in these machines).  Sixth, look for spares for the headwheel power amp transistors and the darlington transistors used in the proc amp section and elsewhere.
 
You are right in thinking that your vacuum should be at 35 inches.  I would run the machine at 70psi.  Hopefully the replacement of the nylon fittings may solve your problems with both.  The guide on the head is opened and closed manually for thread-up.  If you still have lockup problems after these drastic measures, then yes, look for stuck relays or board-level issues.
 
On our machines, the native TBC never quite tamed the jitter on the leading edge of sync that many of our off-air tapes contained.  You may need to look for alternative TBCs.  
 
Hope this is helpful.  Feel free to call if you have further questions.
 
Steve
 
Steve Greene
Audiovisual Archivist
Nixon Presidential Library and Museum
(301) 837-1772

>>> jwalko at scenesavers.com 5/26/2009 9:57:30 AM >>>

Hello Group: Well*a bit of exciting news*at least for me.  We've acquired three TR-600 Quad machines.  Unfortunately, one had to be reduced to parts to move it, but at least we have the parts, including motors, control boards, spare heads, etc. I need some help and advice from the group. We've identified the one machine that we feel has the best chance of being operational again.  This past weekend, we ran power and air and powered up the machine.  We check the test points in the power supply and everything appears to meet proper voltage parameters and the voltage appears stable.  There are no air or vacuum leaks that we can tell*so this appears good.  However, we are not getting stable video or any audio (see below).  I would appreciate some advice. 1.       We are running the air at about 55 PSI (adjusted at the machine*120 from the air compressor).  Vacuum is at 20 inches.  According to the manual, this should be a little higher, but 20 is the highest we can get it to peak.  Adjusting the air pressure didn't affect the vacuum.  Vacuum being at 20 does not appear to be causing any problems, but I am wondering if there is something we are not seeing.  2.       When we put the machine into thread mode, the capstan releases and the tension arms move up and out of the way.  The arm on the head drops to allow threading.  When we hit stop to take it out of thread mode, the arm on the head does not automatically move back to position the tape against the head*should this be automatic or do you have to manually close this arm?3.       When the machine is threaded and the tape properly seated, the vacuum goes off the dial.  I assume this is normal (sort of like putting your hand over the suction end of a vacuum cleaner).  Is this correct?4.       We get a video signal, but it is all broken apart.  We were getting a "lock" error, but are able to correct this by adjusting the capstan speed.  But the video is the wrong color (appears as if Chroma is all off).  Any thoughts as to what to look for (perhaps a board in the system).5.       We get no audio unless we step on the foot switch.  If we manually turn the reels while depressing the foot switch, we get audio (both in forward and reverse), however as soon as the foot switch is released, audio immediately goes away.  We thought this might be related to the capstan, but the audio goes away even before the capstan is fully engaged.  Perhaps a relay is sticking or is bad.  Any ideas? A couple of other items.1.       We were feeding synch from a synch generator2.       We re-seated all the boards (with the machine powered off)3.       We tried two different heads*both heads appear to have slight burnishing, but are not in bad shape.  Neither made a difference.4.       One of our Engineers used to operate one of these machines years ago for a TV station he worked for*so he is somewhat familiar with it*but it was a long time ago.5.       We have a second machine that is complete*but the air fittings are cracked (they appear to be nylon with push in connectors).  We also get no vacuum on that machine, so it would need some work before being operational.  Not sure why no vacuum*it could be related to the air leak or the vacuum pump*6.       We have at least one spare of everything*and are willing to try some things to get this system operational.7.       Both machines were taken out of service at about the same time*and haven't been operated in years.  One machine (the one we are working on) has 3200 hours on the machine*the other has about 5000 hours (the one that has the air leak). Any TR-600 experts interested in coming here to help?  We could discuss reimbursement for your time and travel. Please call me at 800-978-3445 or email me any thoughts that might be helpful (I.e. things to check/test/look for, etc.).
Thanks; John WalkoMedia Archive ManagerScene Saverswww.scenesavers.com800-978-3445513-708-1474 (cell)859-291-5100 (office)   John WalkoMedia Archive ManagerScene Saverswww.scenesavers.com800-978-3445513-708-1474 (cell)859-291-5100 (office) 


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