I've got a Yamaha RX-A730 receiver that has a problem with the VFD's power supply. Specifically, the transistors that provide the switching to convert DC to AC are overheating.
When I got this receiver, the VFD was not working at all. I noticed the burned out transistors, so I replaced those, but that didn't fix it. I found a replacement VFD display and swapped that out, and it looked like things were working fine. However, the transistors I replaced overheated again.
The schematic for the circuit is shown below. If you need more details, you can google for the service manual (same as the one for RX-V675).
What would you suggest I check out next?
When I got this receiver, the VFD was not working at all. I noticed the burned out transistors, so I replaced those, but that didn't fix it. I found a replacement VFD display and swapped that out, and it looked like things were working fine. However, the transistors I replaced overheated again.
The schematic for the circuit is shown below. If you need more details, you can google for the service manual (same as the one for RX-V675).
What would you suggest I check out next?
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