UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Bush DAC90A hum

theredhouseinn · 1st Dec 2021, 6:59 pm

Disconnect the end of R17 the heater dropper, the connection that goes to the rectifier heater, the first one in the chain, whilst the set is switched on. If the hum goes, then it is a heater chain problem. If the hum dies as the cathodes go cold then the hum is coming from elsewhere. Don't try this if you are not used to working on live sets.
John.

1st Dec 2021, 6:59 pm	#25
theredhouseinn Hexode Join Date: Jan 2013 Location: Kelvedon, Essex, UK. Posts: 273	Re: Bush DAC90A hum - AGAIN! Disconnect the end of R17 the heater dropper, the connection that goes to the rectifier heater, the first one in the chain, whilst the set is switched on. If the hum goes, then it is a heater chain problem. If the hum dies as the cathodes go cold then the hum is coming from elsewhere. Don't try this if you are not used to working on live sets. John.