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If you can find a ctc-39 schematic it will be very similar...ctc-39 is same as 38 with the addition of automatic tint control.
The device with the disc is likely the degaussing thermistor...it is in the 400 volt AC portion B+ rectifier circuit, directly after the power supply transformer. If it opens, which is common, you will have low or no B+. CAUTION: there is 420 volts DC with a lot of current capabilites at the B+ supply.
If there is a burned resistor, you likely had a short in a filter cap and this caused the resistor to burn...have seen this many times on these sets. Would recommend replacing all those power supply filter caps or at least the one that the burned resistor connects to. Also shorted diodes in the power supply are common. Use a 60-w lightbulb in series with the powerline when you make the power supply repairs to serve as a short indicator (if bulb lights bright and stays bright...there is a short still). This will prevent further damage and help diagnose where the short is if still present.
Also...the normal heat from resistors often causes burned wiring and terminal strips in these sets...you'll just need to replace the wires and install a new terminal strip.
Yes the tuner is kind of difficult...it has to come out with the chassis, there is no plug arrangement. What I have done is to remove the chassis bottom screws and leave the chassis hooked up in the cabinet and insert something like a book or video tape to prop up the back of the chassis so I can make test connections. I'll use alligator clip leads to hook up the voltmeter, not putting my hands under the chassis while it's plugged in, in case it were to fall.
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