eBay sale 👉 www.ebay.com/i...
I picked up this Yamaha CR 450 a few months ago and was told the meter lamp was burnt out and the left channel had distortion. The CR-450 was released in 1976 as a replacement for the CR-400 which was having issues powering the lower impedance power hungry speakers that were being released in the US. They doubled the output transistors and power handling while also beefing up the power supply and removing the current limiting circuit. It can produce nearly double the 32 watt per channel output at 8 ohms to a 4 ohm speaker. It sounds very warm compared to the rest of Yamaha’s 70’s lineup and is one of my favorite looking so I was very excited to get it working!
The left channel distortion sounded to me like a power supply issue but I started by troubleshooting it and ended up finding a horrendous previous repair job on the output transistors. After fixing that I moved into recapping most of the receiver and replacing all of the output transistors. I also updated the lamps to LEDs and added a couple of additional LEDs to light the tuning meters.
Parts list 👇 docs.google.co...
Known bad transistor list 👇docs.google.co...
XraytonyB video on transistor replacement 👉 • How to Find Substitute...
Chapters:
00:00 Intro and background info
00:29 Parts list
00:41 Electricity warning
01:21 Start the timer & initial diagnosis
01:56 Somebody used sub optimal output transistors
02:09 Testing with speakers for the first time
02:33 Checking the relay
02:53 Reading the schematic + checking rail voltage
04:59 CABLE MANAGEMENT
05:16 Checking the bad transistors
06:31 Replacing the Output Transistors
07:36 Replacing the 3A speaker protection fuse
07:40 Washing Mica Insulators & Installing new output transistors
11:20 Did we fix the issue?!?
12:20 Removing & cleaning the knobs & faceplate
13:34 Replacing the center meter lamp
14:57 Filter capacitors
17:19 Finishing the Meter LEDs
18:41 Dial Pointer LED swap
19:45 Cleaning & Lubricating the Controls
23:36 Testing the capacitors
24:21 Known Bad Transistor Replacement
25:30 Adjusting Bias (Idling Current)
27:21 Reassembling the faceplate and knobs
27:59 Outro and listening sesh
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My name is Matt. I live in Washington State and create content around vintage stereos and other audio equipment. I approach the hobby from a technical standpoint and am learning about circuit design and reparing and calibrating amps, turntables, speakers, etc. I really appreciate a good aesthetic and the vintage stuff fits my taste.
Instagram: @Shuksanaudio
Tik Tok: @Thedealydeal
Негізгі бет It's so EASY to repair: Yamaha CR 450
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