Recent content by Matt Mincer

Hey Folks, I'm working on a Pioneer CT-F700. It was brought in for a belt and tire job but the auto stop doesn't work. Everything is turning fine but when it gets to the end of the tape on play, rewind, or FF, the solenoid doesn't activate. There's nothing blocking the mechanism. Any thoughts...

Hey folks, I have this EQ a guy brought me to fix. The 250 and 2khz displays don't respond even when I inject those frequencies directly into the input. He's also saying the pink noise generator isn't working but I haven't gotten that far yet. All of the chips are plugins so I've been able to...

Yeah, in a receiver and also solid state.

Hey, I have noticed that I replace a lot of transistors and caps in amps and power supply circuits but rarely in radio circuits. Is this a known thing or am I imagining it? If it is a thing, why? Do OEMs use better components in radio circuits? Is it because radio circuits use less power so...

Hey folks, I have an SX-3600 with no FM. No static regardless of where it's tuned, mute on or of, no deflection on the tuning meter. All of the other functions on the receiver work. Any ideas? I'm going to poke around with my meter but I'm wondering if there's a known issue. Thanks Matt

Hey All, I have a 4270 on the bench and when I turned the power on, the speaker relays took a super long time to engage. And when both speaker switches were on, it was painfully slow. I replaced C806, 807, and 808 on the power supply board and it now works perfectly. I also replaced the...

Hey Folks, I'm working on a G-7000 that is working perfectly. The owner swears up and down that the power light should switch from red to green depending on whether it is in protect mode but this one stays red. The relay clicks as expected and the thing sounds perfect. Idol current and voltage...

So the pictures below were the speaker switch from a 700M. The 4 parts sitting on the transformer were originally 2 parts that have broken (not by me btw). Does anyone know where I might find a replacement switch? I’ve checked eBay but with no luck. Thx Matt

I think we got it figured out. There were several cold solder joints, particularly around the heatsinks for Q25, Q27 & Q26, Q28. Each channel has a shared heatsink for 2 transistors. There were a few others too but those were the main issue. Thx for all the help! Matt

Well, it turns out that I'm a freakin' idiot! One section of one of the power supply caps was shorted. Soooooo, BUZZZ! This model has dual power supplies. Each channel has one cap with two sections. One for B+ and one for B-. B- was dead. Thx Matt

Yeah, I know it's not a good way to test transistors. Still, you can sometimes tell if they are shorted. I plugged my iphone into the main in and still got the buzzing. Also, when I pull the signal input plug (J21-J23) off of the power amp board, I still get the buzz. So it's got to be on the...

Hey All, I'm working on a 2330B where the left channel of the power amp is distorted and buzzy. I am positive it is the power amp because it does even when the signal input on the board is disconnected. I replaced all of the electrolytic caps on the board. All of the transistors test good (in...

Hey all, I'm working on an M2 where the right channel is intermittently distorted. When I put a 1mhz signal into the input, the output is only the bottom half of a wave. But the kicker is that it's intermittent. As I'm typing this, the scope shows a perfect signwave and the audio sounds great...

C 4 & 5 both test okay with my ESR meter. Agree that they are underrated but they seem to be okay. Power supply voltages are 13.5, -23.5, + 25.5. Diodes test okay in circuit. 1.3 V across R1. The stereo bulb is blown so it's not that. I'll let it cook a while and see what happens. Thx Matt

Hey All, I have an SX-434 on my bench for the 2nd time. I replaced F5 a few weeks back and it worked fine for about 30 minutes. Then it blew the fuse again. Any ideas as to what might cause the issue? Thx Matt