Can remote control chassis cause major problems in multiple sections?

[Tubejunke]

Well, tonight I replaced the 4 electrolytics that remained in the Space Command and also a 27K 2w resistor to still see no improvement. I thought for sure the thing would come to life or at least some major change in performance. To those who dont know I am working with a model C4007R with 18C24Q chassis. I am about stumped with the exception of wondering if some kind of short in the remote control chassis could cause this set to have almost no vertical sweep and volume adjustable hum in the sound. The power lead to the remote unit has to be plugged in to fire up the set. The only other thing I have questioned is the use of a 5u4 in the place of a 5au4 but everyone seems fairly certain that the swap is OK since the set is producing B+. If the remote is part of the circuitry I guess it would be logical to think that it could cause some kind of problem but I would think not in 2 or 3 different sections. Although I have bragged on how unused this set looked when I bought it I will say I did find evidence of some repair in the form of 2 .1 600v redish versions of orange drops. Maybe I am the victim of someone elses botched repair attempt and some cap is hooked up wrong. One of them is in the vertical section. This set has some strange and uncommon problem I think. I would love to figure out what it is. If that remote unit were the problem the whole time I will be pissed but happy if that makes sense.....

[Chad Hauris]

You may have done this already but double check all the voltages
in the vertical circuit against the schematic/photofacts. It may not be good enough that B+ from the power supply is good...a bad capacitor could have caused resistors to overheat and open, so that even when you re-cap it a problem remains.

Also check the actual circuit in the set to the schematic, this will help tell you if someone made a wrong connection in a past repair job.

[Tubejunke]

Chad, I have similar schematics by Electronic Technician Circuit Digest but nothing exact. I need to get a Sams I think. Tonight I found a 1 watt 270k resistor that measured like 350k. It connects to the vertical osc and a 10mfd electrolytic ar 450v. I only have a half watt replacement so I may have to wait till my next trip to the parts store. I hope this is at least a big part of my problem. I would be happy to see any kind of positive change in performance. I have changed 6 or 7 other resistors out of 20% tolerance and saw no improvement. Maybe this will be the one. Wish me luck!!!

[drh4683]

Your space command chassis shouldnt be causing any of your symptoms. Unfortunatly I dont have a schematic for 1958 zenith line. I will assume you have space command 400 in there. Basically, your speaker output lead connects to the space command chassis and is stepped in 3 incraments by adding resistance in series with the output. Feel confindent that this is not causing any of your sound problems, as if a resistor were to be open, you would have nothing from the speaker. When you move the selector switch on the space command chassis to manual, you also are disconnecting the sound input to the space command chassis and passing the output through the switch. The space command chassis is totally independent from the tv chassis. In other words, the space command chassis does not supply other circuits within the TV chassis a supply voltage etc.

A pointer for your vertical problem, yes, capacitors are generally prime suspects however high resistance resistors will go way off value and cause minimal vertical sweep. Trace the wire that connects the vertical lin pot back to the vertical output tube, there is probably an 82K or some sort of higher value resistor in series with that. If your resistance doesnt seem to be at all of what it should be double check by clipping one lead off that resistor and check again. Keep in mind your resistors should be within a tolerance of +/- 20%
From experience with many sets, you only will need to replace the black beauties and nothing more (as far as capacitors go). You will be surprised how much resistors change value, in perticular anything over 1Meg.
Should resistors in the described circuit be ok, I will go deeper into details. Just want to avoid unessisary confustion

By the way, does the space command chassis work? Any space command remote will make it do something, either a 300, or 600 will work if youve got one lying around. All space command sets using the mechanical remotes use the same fundamental frequencies. Space command chassis will always need to be recapped, as they use about 7 or 8 black beauties if its a 4 function remote. We'll focus on that later. Ive got alot of experience with space command circuits, shouldnt be a problem if there is one.

[Tubejunke]

Doug, thanks for the info. As far as the Space Command chassis goes I dont know if it works or not. I have switched it on and dangled a ring of keys around it and got no reaction. I have no remote. Someone posted and said that the keys would usually cause some reaction from the unit. I have done a lot of investigation into the use of a 5u4 in the place of a 5au4 and the conclusion is that it is not a suitable or recommended swap so I have ordered one to try the set for the first time with the correct tube. I dont really think the bad tube swap would cause the vertical, sound, and lack of signal problems but the set needs the right tube. It came with the 5u4 but the schematic calls for a 5au4. That is the one thing left that I know is wrong. After that I dont know what direction I will go. I have replaced several resistors out of 20% and some at 10% if they had the silver band. I have replaced all of the capacitors with the exception of the ceramic discs and a couple of the blood red versions of orange drops. I dont know what they are called. They are mostly mounted on potentiometers. I have swapped out the vertical tubes and checked all the others for shorts and emissions. Like I have said before in other posts I should have seen some improvement by now for sure and it is real frustrating to have done all this to still be standing at square one. I guess eventually I will replace some overlooked item and the set will come to life and work perfect for years. Hell, it will be brand new virtually.