u/Ancient_Principle_65

After a couple of weeks of troubleshooting the scope(bk 2120) is functioning once more with full sweep.

Recently acquired this from local vocational school. At first there was no horizontal display besides a small dot; found that problem to be a faulty resistor. Whenever the new resistor was soldered in it was found there was also a faulty transistor as there was still no horizontal output, however when I alligator clipped the resistor with a good one before I replaced the transistor it worked. I have been stumped since. I have a copy of the wiring diagram if needed for anyone.

After advice to clean the boards before I do anything crazy with this stereo I noticed an abnormality on the fm intr board. All the spots where the symbol is there is a resistor, however in this spot (r206 and r221) there is not. Is it missing or am I ignorant?

I recently stumbled upon this unit in my dads attic. It’s aux works however fm and am is dead. Is there any way to troubleshoot the unit without an oscilloscope or am I screwed?