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Old 07-23-2009, 11:01 AM
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jshorva65 jshorva65 is offline
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"Cathode Restorer" CRT Tester Question

I wasn't sure where to post this Early Color (and/or B/W) TV Test Equipment question. Early Color TV seems like as good a place as any, I guess. Does anyone know where I might find a schematic for a REM Electronic Instrument "Cathode Recovery Unit and CRT Tester" (no model number found on either the exterior or interior of the unit, its only included documentation is a single page of operating instructions on the inside top cover)? According to legend, at least, this unit is a direct ancestor of the Beltron model 2972-E "Cathode Recovery Unit and CRT Tester" device. I have heard very good reviews of this unit from a colleague in Akron and of the Beltron from another colleague. I just purchased one of these REM units recently. Since "Big Dave" is a fellow native of Warren, Ohio who currently lives just across town from me and owns a Beltron 2972-E, he and I compared test results for some tubes between his Beltron 2972-E, my Sencore (just calibrated per its manual's calibration procedure) CR-168, my B&K 465, and my newly-acquired REM tester. It is clear from the tests of these known-good tubes with our known-good testers that the REM unit is in need of repair.

I began troubleshooting without a schematic, locating and replacing any components found to be out of tolerance. I re-formed a 16uF/450V capacitor and confirmed it to be in good condition, and replaced three 47K and three 100-ohm resistors (located in each gun's meter circuit, the 47K in series with and the 100-ohm shunted across each meter) which were outside rated tolerance with new units measuring within 5% of nominal values. Still, tubes which test as Good or Excellent on the other three testers are showing Bad on this one. There is a large "potted" circuit assembly (about 2-1/2" diameter and 3/4" thick) inside the unit, with several leads connected to the various switches, meter movements, and other discrete components. To troubleshoot the device further, I will need to determine the contents and connections of the "black box" assembly.

The key advantages of this model over some others (such as the Sencore and B&K units I mentioned) are: its use of a limited-current Recovery process instead of the capacitive-discharge "flash" method which tends to cause "cathode stripping" and destroy tubes; individual meter movements for all three guns in Test mode; and a built-in mechanical timer for the Recovery function. Its disadvantages are: absence of a Short test function; fixed Heater voltage (for use with 6.3V tubes only); absence of Gun Balance provisions (both the B&K and Sencore units can set fixed "balance" points via variable G2 voltages from which some calculations can determine whether Balance and Tracking are acceptable); and absence of a Tracking test (only the Sencore can provide a direct "Good/Bad" Tracking reading directly, while Tracking quality can be determined indirectly via calculations applied to test readings from the B&K). The Beltron 2972-E supports Heater voltages other than 6.3V, but also lacks direct tests for Shorts, Gun Balance, and Tracking.

Here are some photos of the REM Electronic Instrument "Cathode Recovery Unit and CRT Tester."
Attached Images
File Type: jpg REM CRT Tester 001.jpg (77.1 KB, 18 views)
File Type: jpg REM CRT Tester 002.jpg (85.2 KB, 26 views)
File Type: jpg REM CRT Tester 003.jpg (74.7 KB, 13 views)

Last edited by jshorva65; 07-23-2009 at 11:05 AM.
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Old 07-23-2009, 01:16 PM
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I picked up a REM earlier this year; it is one of the "keepers" from the TV shop I am cleaning out. I know there is some paperwork with it-I'll have to check for a schematic. I haven't fully tested it yet, but have heard good things.
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Old 07-23-2009, 04:45 PM
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Hi;
I also have a REM unit and am quite happy with it. It would appear that mine is a later version since it incorporates a voltage selector to better match it to the crt.


[IMG][/IMG]


When I first picked up this piece I was a little unsure of it's reliability and went on a "hunt" for a schematic. I scoured the internet and asked everyone I could think of...but no schematic was to be found. I have the original owner's manual and it does not include a schematic, but it does have a testing procedure that can be used to check the accuracy of the unit. In order to perform the test you must have the test adaptor which connects via the 21" crt socket.

I also have a Beltron unit and have done some A to B comparisons and found both units to be very reliable and accurate.

Way back when I was just a newly graduated college boy I had a job in a TV repair place. We sold and repaired TV's to be installed in all of the local hospitals. There were a LOT of TV's that went through that place. It was like a TV repair assebly line. Once I hit my stride I was cranking out an average of 10 to 15 sets a day.

They finally decided to invest in a CRT Rejuvinator. They were a really "cheap" outfit so this was a BIG DEAL. They "auditioned" quite a few different units that were on the market and finally decided on the REM. I'd gotten to use it a few times and always liked it. When I finally left the place and decided to invest in a REM unit of my own...they had been bought out by another company and that was that. I'd always regretted not having a REM, that is until the dawn of Ebay. As much as I dislike a lot about Ebay, you can find things on there that you could spend a lifetime looking for anywhere else.

Good luck with your REM. Should you need a copy of the test procedure I'd be happy to send you a scan.

Bob



Quote:
Originally Posted by jshorva65 View Post
I wasn't sure where to post this Early Color (and/or B/W) TV Test Equipment question. Early Color TV seems like as good a place as any, I guess. Does anyone know where I might find a schematic for a REM Electronic Instrument "Cathode Recovery Unit and CRT Tester" (no model number found on either the exterior or interior of the unit, its only included documentation is a single page of operating instructions on the inside top cover)? According to legend, at least, this unit is a direct ancestor of the Beltron model 2972-E "Cathode Recovery Unit and CRT Tester" device. I have heard very good reviews of this unit from a colleague in Akron and of the Beltron from another colleague. I just purchased one of these REM units recently. Since "Big Dave" is a fellow native of Warren, Ohio who currently lives just across town from me and owns a Beltron 2972-E, he and I compared test results for some tubes between his Beltron 2972-E, my Sencore (just calibrated per its manual's calibration procedure) CR-168, my B&K 465, and my newly-acquired REM tester. It is clear from the tests of these known-good tubes with our known-good testers that the REM unit is in need of repair.

I began troubleshooting without a schematic, locating and replacing any components found to be out of tolerance. I re-formed a 16uF/450V capacitor and confirmed it to be in good condition, and replaced three 47K and three 100-ohm resistors (located in each gun's meter circuit, the 47K in series with and the 100-ohm shunted across each meter) which were outside rated tolerance with new units measuring within 5% of nominal values. Still, tubes which test as Good or Excellent on the other three testers are showing Bad on this one. There is a large "potted" circuit assembly (about 2-1/2" diameter and 3/4" thick) inside the unit, with several leads connected to the various switches, meter movements, and other discrete components. To troubleshoot the device further, I will need to determine the contents and connections of the "black box" assembly.

The key advantages of this model over some others (such as the Sencore and B&K units I mentioned) are: its use of a limited-current Recovery process instead of the capacitive-discharge "flash" method which tends to cause "cathode stripping" and destroy tubes; individual meter movements for all three guns in Test mode; and a built-in mechanical timer for the Recovery function. Its disadvantages are: absence of a Short test function; fixed Heater voltage (for use with 6.3V tubes only); absence of Gun Balance provisions (both the B&K and Sencore units can set fixed "balance" points via variable G2 voltages from which some calculations can determine whether Balance and Tracking are acceptable); and absence of a Tracking test (only the Sencore can provide a direct "Good/Bad" Tracking reading directly, while Tracking quality can be determined indirectly via calculations applied to test readings from the B&K). The Beltron 2972-E supports Heater voltages other than 6.3V, but also lacks direct tests for Shorts, Gun Balance, and Tracking.

Here are some photos of the REM Electronic Instrument "Cathode Recovery Unit and CRT Tester."
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