I messed up...

Описание: Last year I dove back in to working on vintage stereos after a 10 year hiatus and my first big project was restoring a Pioneer SX 434 for a friend along with some speakers. Finished the restoration and delivered the system but a couple of months later the phono stage stopped working properly.
Fast forward to December 2023 and I made the few hour drive to my friend's house with parts and soldering tools in hand. I updated the phono stage and it worked great. Unfortunately, I decided to test the receiver with the heatsink removed from the output transistors and it caused major issues. I had to bring it home and am now diagnosing it and hopefully fixing it for the last time.

I'm a bit embarrassed that this happened. I'm still learning and am by no means an expert which is why I tend to work on stuff for my friends instead of for other people. I've also come a long ways since I first restored the receiver last year and leaving the heatsink off was one of those you'll-only-do-it-once mistakes.

Timeline:
00:00 Intro and explanation of the failure
01:44 The current issues
02:29 Troubleshooting
05:25 Rant about old Service manuals and parts labeling
07:11 Troubleshooting Cont.
08:21 Sneak peak at future projects
08:46 Checking for bad components in the pre amp
10:21 Installing new parts
11:08 Finding the correct output transistor replacements
13:13 First test on the dim bulb
13:40 Checking voltages and reassembly
14:16 Full test

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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
Some of my favorite brands are Yamaha (CRxx20 series receivers, CA 1010/2010 integrated amps), Harman Kardon (Twin power receivers 430, 630, 730, 930), and Sansui (X0X0 series receivers, AU 717, 919 integrated amps).

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...

Tools:
-Ratcheting screwdriver https://amzn.to/3WihZED
-Needle Nose pliers https://amzn.to/477nQmr
-Lead forming pliers https://amzn.to/3JsB1oK
-Capacitor drain tool https://amzn.to/4oD6HGZ
-Wire strippers https://amzn.to/43r26iU
-Magnetic Helping Hands https://amzn.to/4o5BAnF
-Plastic Rocket Sockets https://lovemyswitches.com/rocket-soc...
-Fiber glass pencil for cleaning metal contacts https://amzn.to/3Jdn0eG
-Digital caliper (Don’t cheap out on one like I did, this one is nice) https://amzn.to/3WS5cJ7

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