Roland Juno-106 Synthesizer Troubleshooting/Repair Quiet Voice

Today I'm investigating an issue with a Roland Juno-106. Voice #4 is a lot quieter than the others. And it's not a calibration issue. 99% certain it is NOT the brand new voice chips I put in as seen in a previous video. Troubleshooting will confirm that statement. So what else could it be? Maybe something EVERY 106 owner will want to be pro-active about mitigating?

This video is posted for general information about my experiences. Always observe safety working on electronics, and never tinker around inside power supplies without first unplugging the power cord. De-soldering components on the Juno-106 must be done VERY CAUTIOUSLY to avoid lifting very tiny delicate traces. If you're not sure about anything, there's no shame in taking your instrument to a qualified service technician.

Timestamps
0:00 Intro + Symptoms
0:35 Voice Chip Swap Test
1:06 Looking at the Wave Chip output
1:56 Waveform Chip replacement
2:23 Testing
2:51 Voice Board inspection and Remedy
3:19 Re-testing, did it work?

Be sure to check out my cool eurorack modules in my Reverb Store :D

Sequential Drumtraks Drum Machine Repair

Today I'm investigating issues with a Sequential Drumtraks. While it is making sounds, the display is glitching out and the control functions are not working. In the end it was only incidental I was able to get it working again, for reasons I don't fully understand. The same phenomenon happens with my Drumulator, that's how I knew what to check for. It's my hope posting this video, that someone more knowledgable will be able to comment about this phenomenon.

This video is posted for general information about my experiences. Always observe safety working on electronics, and never tinker around inside power supplies without first unplugging the power cord. If you're not sure about anything, there's no shame in taking your instrument to a qualified service technician.

Since filming the video, I've discovered the batteries are still made in Japan. Also, the numbers on the battery may or may not necessarily be a date code. My new battery says 2132, so maybe it was made in 2021? Since the manufacture date and date installed may differ by a couple of years, I now write a date on the battery with a sharpie when I install it.

Timestamps
0:00 Intro + Symptoms
0:28 Power Supply investigation
2:10 Battery
2:28 Data Bus Check
4:08 About Cleaning IC pins
4:28 Last ditch effort and suddenly it's working???
5:38 Short demo

I design analog Eurorack modules, check my Reverb store for availability.

Can I Revive Kenwood DX-7030 DAT Machine Recorder?

Today I'm investigating issues with a Kenwood DX-7030 DAT Recorder.
The door opens and closes, but doesn't play the tape.
There's not a lot of mech service video content on this model.
And I have no service manual.
Can I get this thing working?

This is just a summary of about 10 hours of inspection, fiddling, proding, and poking.
Not including watching a load of DAT mech cleaning content.
Big shout out to 12voltvids
There you can see more detailed tips for cleaning DAT mechanisms.

Timestamps
0:00 Intro and Symptoms
0:37 Tape Mech Breakdown
2:25 Take-up Rollers
3:10 Switch cleaning
4:14 Results?

Be sure to check out my cool eurorack synthesizer modules in my Reverb store.

Oberheim Matrix-12 Synthesizer Power Supply Issues RESOLVED

In this video I show what I did to resolve my power supply issues on the Oberheim Matrix-12 analog synthesizer. Symptoms were intermittent non-boot, locking up, and the dreaded Voice 1 Processor Malfunction message. Along the way I'll talk about how the power supply works and how it is different than many synths from the era prior to this. Even though the Oberheim Xpander is a little different than the Matrix-12, its power supply works exactly the same. This may not enable you to fix your Matrix-12/Xpander completely, nor answer ALL questions you may have...but hopefully it will be helpful information.

YOU ASSUME ALL RISK WHEN REPAIRING YOUR OWN ELECTRONIC INSTRUMENTS! There's no shame in asking a friend for help or taking it to a reputable synthesizer technician. BE SURE TO UNPLUG THE SYNTH PRIOR TO DOING THIS KIND OF WORK.

0:00 Introduction
1:10 Getting Started
1:54 Dealing with an SMPS
3:16 Why did Oberheim use an SMPS?
3:40 Why I'm NOT going to troubleshoot this power supply
4:38 Power Supply Restoration and Results


Here are the Mouser parts numbers:
Power Entry Module - 871-B84771A0001A000
2W Shunt Resistors 0.1ohm - 667-ERX-2SZGR10V
sorry I don't have capacitor numbers, I did that work 2 years ago

Arturia Beatstep Pro Sequencer Repair Project

Did you know I have interesting things listed on Reverb? Check it out now. In this video I attempt to repair my Arturia Beatstep Pro sequencer controller. It is having intermittent power problems, I want to replace the USB port w/ a different kind. My warranty ran out in September, so no wukkas. This is only my second project doing SMT (Surface Mount Technology) type work, and I find myself needing to revise my plans. Next time I will buy some solder paste and do it right, lesson learned. At the end of the video I test my work by doing a little Acid House w/ a Korg MS-20 synthesizer and a Roland TR-8 drum machine. If you like synth and electronic guts click the LIKE button.

You may have read my post on my previous repair. I'm not sure if it didn't hold, or there was a problem w/ the USB jack/cable. Whatever the case, it was only a temporary fix.

Arturia Beatstep Pro Sequencer USB Port Jack Easy DIY Repair

Any system is only as strong as its weakest link.

Enter the Arturia Beatstep Pro Sequencer, tons of user reviews boast solid construction seemingly built like a tank. On the first few uses I would be inclined to agree. However after about a dozen uses the USB port jack on mine has become intermittent. Symptoms include sudden power blackouts and reboots, even when not touching the USB cord. You don't have to play out live to a crowd to know, this is no bueno. I am careful and take care of my gear. I am especially careful with the USB port and its cord, however I run a bunch of other connections back there and the wires usually hang up with the USB cord. Why is this happening?

One condition could be contact fatigue. If you plug/remove the USB cord a lot, the little contacts could become worn away. You will frequently see this in older cell phones. But more likely as in my scenario, the lead-free solder on the USB ground pins disintegrated resulting in a faulty solder joint at the circuit board. It would be too easy to blame the RoHS standard for requiring lead-free solder, which is structurally deficient for such a use. But if I worked in a factory around solder all day long, lead-free is the way to be. What can be done about it?

If the item is still under warranty you could send it to the company and they can fix or repair the item. There may be a repair charge if the company deems the issue to be caused by negligence. And who's to say? Even if there is no charge, you could get your sequencer back and have the same thing happen again. I'm only mentioning all of this because if you choose to repair the USB port yourself, it WILL void your warranty. Also, if you're not careful and touch something electronically sensitive, you may accidentally damage something else. I'm not liable for anything you do, so be careful not to shock yourself. If you're not confident in doing these things, there's no shame in getting an electronics friend or service tech to help. You have been warned. Now let's fix this thing already.

1. Flip the sequencer over and remove all the black screws. Remove the metal back plate. This will expose the circuit board. Remove all the little screws holding the circuit board in place.

2. In this orientation, pull the circuit board away from you to dislodge the minijacks from the case. Then lift the edge closest to you up and away. If this isn't happening, check you have removed ALL the little screws, it may be easy to miss 1 or 2.

3. Flip the circuit board over and note the location of the USB jack near the power switch.

4. Using regular rosin core solder (I use 60/40 from Radio Shack), make new solder joints on the two GROUND pin locations at the locations shown by red arrows. Make sure the pins get soldered nicely to the circuit board contact pins here. I needed a magnifier to see the work area.

5. Put the circuit board back in and secure it to the case with the screws. This is the time to plug in and test it, making sure you DO NOT touch any of the electronic components inside while you do so. At this point you will be able to wiggle the USB cord lightly and make sure it does not blink the power. If so, you'll need to do it over. Or there may be something else going on. Hopefully this has been helpful, this is what I did to restore mine to working order. If everything is good, you can go ahead and put everything back together.