mr fixit 52
- Jul 9, 2021
- 4
- Joined
- Jul 9, 2021
- Messages
- 4
Help! I recently found an overheating issue with 2 5w 330ohm ceramic resistors in my guitar amp(known issue) which was causing crackling,distortion and lack of volume, even when running the amp on the clean channel.
Problems identified were discoloured resistors,loose connections and lifted tracks on PCB. Tracks I have repaired and 2 ceramic 10w 330 ohm have been fitted with heatsinks and thermal paste and a 5mm gap under each to improve air flow,which has fixed the unwanted noise issue and amp will run well but still a lot of heat generated.(I set up a test rig(see pic) which included a 120mm Arctic pc fan,driven by a 9v battery,which provided a further significant reduction in temperature.)
I now have 2 10w 330 ohm Arcol aluminium housed resistors,which I am intending to mount off PCB on a heat sink with thermal paste then bolt direct to chassis.Will that significantly reduce temperature? Problem is,I only have an area of 70mm x 220mm between PCB and rear of chassis to fit heatsinks.Most heatsinks I have seen are too big to fit.Any suggestions? If I need to install a fan,then I will be needing a 230v to 12vDC(fan current voltage 0.16A or 0.20A),any suggestions on a suitable power supply?
1 resistor is handling +42v input, +16v out and resistor 2 is handling -42v input, -16v out.Any advice on successfully resolving this issue will be greatly appreciated and I wont be binning the Amp!
Many thanks
Problems identified were discoloured resistors,loose connections and lifted tracks on PCB. Tracks I have repaired and 2 ceramic 10w 330 ohm have been fitted with heatsinks and thermal paste and a 5mm gap under each to improve air flow,which has fixed the unwanted noise issue and amp will run well but still a lot of heat generated.(I set up a test rig(see pic) which included a 120mm Arctic pc fan,driven by a 9v battery,which provided a further significant reduction in temperature.)
I now have 2 10w 330 ohm Arcol aluminium housed resistors,which I am intending to mount off PCB on a heat sink with thermal paste then bolt direct to chassis.Will that significantly reduce temperature? Problem is,I only have an area of 70mm x 220mm between PCB and rear of chassis to fit heatsinks.Most heatsinks I have seen are too big to fit.Any suggestions? If I need to install a fan,then I will be needing a 230v to 12vDC(fan current voltage 0.16A or 0.20A),any suggestions on a suitable power supply?
1 resistor is handling +42v input, +16v out and resistor 2 is handling -42v input, -16v out.Any advice on successfully resolving this issue will be greatly appreciated and I wont be binning the Amp!
Many thanks