Bad diodes, or a cracked/corroded solder joint between the transformer and the rectifier. Or a bad qnd very leaky filter capacitor. Any loud hum/buzzing coming out of the transformer? Step 1 will still be disconnecting the transformer and measuring it with and without a load.
6 months ago | 0
Can you measure then output of the transformer with it disconnected from the circuit? I’m guessing pic one (which test is a horrible AC waveform) is with the transformer still all hooked up the bridge rectifier which is then connected the main filters and the rest of the circuit. Likely coming further downstream causing the at. Disconnect the transformer secondaries and measure the AC coming out then. Also yes, pic is indeed a bad example of DC voltage.
6 months ago | 0
Modern Classic
Hey all, I could use your help. I'm fixing up my old Sony TC-K96R tape deck and I'm trying to troubleshoot what seems to be a power issue. There is no DC voltage getting out of the bridge rectifier, which is the first thing after the the main transformer. The rectifier itself tests fine. I looked at the waveform coming in from the transformer and that's image 1. Looks weird, right? What could cause that, and could that kill the output from the rectifier? Do I have a bad transformer? Image 2 shows the DC output from the rectifier, which also looks weird (for DC) and is way too low voltage.
6 months ago | [YT] | 1