It's so EASY to repair: Yamaha CR 450

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 👇 https://docs.google.com/spreadsheets/d/1nKSGNtAMdVTtCfPJ-QWretgE-pxqfcVjRHVbkpLzipw/edit?usp=sharing

Known bad transistor list 👇https://docs.google.com/spreadsheets/d/1zE0jlgjpfqeS3fVZ23wvHWG89xoJbi9dETIpIZcztuo/edit?usp=sharing

XraytonyB video on transistor replacement 👉 https://www.youtube.com/watch?v=KKXF-onCwbQ

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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Hey! My name is Matt and I sure do love stereos! I got into this hobby when I was in high school over a decade ago. I had huuuge speakers in my bedroom and way too many pieces of gear (my mom was worried I would become a hoarder haha). I started repairing stereos for friends a few years back and decided to make videos about it! Now I repair gear for people. If you want to send yours in for repair, head to my repair form: https://forms.gle/Tk5xAEkGgVdyZ4w4A

Test equipment: (I earn a small commission if you buy from these links)
-Dim bulb tester! I made mine but you can find them on various websites
-Soldering iron Hakko FX 888 https://amzn.to/3JhyNrK
-Hakko FR 301 solder sucker https://amzn.to/4ogUecy
-Main Multimeter (Fluke 87V) https://amzn.to/45dvqJS
-Get the mini grabber leads for it! https://amzn.to/4qpJzxt
-Cheaper multimeter (Fluke 115) https://amzn.to/4o9y0ce
-Oscilloscope Siglent SDS 1104X-E https://amzn.to/43ovYMU
-Function generator Siglent SDG 1032X (There are newer versions out so finding this used online is the best option)
-Capacitor tester Peak Atlas ESR 70 https://amzn.to/3JjBauK (The price here fluctuates, you can usually find them cheaper on other stores)
-Transistor tester Peak Atlas DCA 75 (you can get the cheaper 55 model but it’s not as good so if you can afford it this is the one) https://amzn.to/4oaW6TS
-Hagerman labs IRIAA (Phone or signal generator gets dropped to phono cartridge level) https://hagerman-audio-labs.myshopify.com/products/iriaa2-inverse-riaa-filter

Chemicals/glues:
-Electronics contact cleaner https://amzn.to/4o7yH5O
-Deoxit D100L for metal contacts https://amzn.to/3WRiXaS
-Deoxit F100L for graphite contacts https://amzn.to/4hps1xf
-Solder flux in a syringe https://amzn.to/4hpNs1f
-Dow Corning 340 Thermal paste (Non conductive) https://amzn.to/4o6f65O
-Freeze spray (Electronics safe) for finding faulty transistors https://amzn.to/4qlDvGl
-Silicone oil for cueing cylinder on turntables https://amzn.to/43osOsw
-Acrylic glue for dustcovers and such https://amzn.to/4o87TSZ
-Mother’s Mag & Aluminum polish for faceplates https://amzn.to/3L70ip2
-Meguiars ScratchX For light buffing https://amzn.to/4ht58t1

Miscellaneous useful items:
-Tuner string https://amzn.to/3Wl6DzK
-Parts organizer bins https://amzn.to/4ht3nfp

PCB Repair:
Eyelets https://amzn.to/4qr8TTH
Punches for installing eyelets https://amzn.to/48LJbmE
Hand drill for enlarging PCB holes https://amzn.to/3WoxWZQ

Instagram: @Shuksanaudio
Tik Tok: @Thedealydeal
eBay: https://www.ebay.com/usr/shuksan-audio