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#1
03-18-2006, 11:10 PM
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Motorola, Need Schematic
Hello,
Does anyone have a Motorola 12VT13R (Chassis TS-23 circa 1949-50?) they could email or send me? I have the chassis on the bench now but as you can see in the photo it's needs more work. Someone replaced all the electrolytic cans on top of the chassis and a few caps underneath. I replaced the remaining caps and electrolytics but the screen result is the same only the audio improved. The selenium rectifiers have been replaced with modern diodes. I need a schematic so I can double check the cap and electrolytic values of the replacement cans. Next I'll start testing resistors. Thanks for any help. Jim 
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#2
03-19-2006, 04:57 PM
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I have the Beitman's '51 book which includes this chassis, but the schematic is hard to read. I'm not sure if I could get a good enough copy for you, but would be willing to try if need be. Some I can tell you about: to one side of the speaker field (the selenium side) there is a 100mf/300v; the other side has a 125mf/300v. The cap connected to the joint of the 2 seleniums is listed as 140mf/150v. Between pins 1 and 2 of the 6AL5 ratio detector you will find a 10mf/50v. It looks like pin 8 of the 6V6 audio output has a 20mf/25v. Pin 3 of the 6J5 goes through a 470K resistor to a 20mf/250v cap. Pin 6 of the 6AU6 audio amp has a 20mf which I think is at 250v but the print is very small. Pin 8 of the 6V6 vertical tube is 100mf/30v while there is a 60mf/250v cap which you will find connected to the wiper of the focus control, among other things. Maybe that will get you started until somebody finds the sams, which should be easier to read then this thing Motorola put out.
__________________
Bryan
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#3
03-19-2006, 07:33 PM
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Thanks bgadow,
The electrolytic replacements are all correct, Thanks for all the values. And thanks to Sean for emailing the schematic. I found a few "Black Beauties" hiding that were a source of the problem. The sets running good now But I'll check some of the resistors anyway. The set still needs a few adjustments as the picture is out of focus on the far left side of the screen(only about 2 inches in from the mask) and on some channels the top 1/3 of the screen is black during a program but commercials go full screen, Why is that? I have a VCR connected as a tuner. Jim
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#4
03-20-2006, 05:10 PM
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If you are looking for the Sam's it's 92-4
Terry
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Linear Mode
