Dead Roland Juno 106 Repair - Synthchaser  

Old Japanese gear are always a joy to work on, good documentation, good layouts, good legends and generally made to be repaired. Even some of their ancient el cheapo tube amps and guitar effects have their schematics glued inside. I have a huge soft spot for vintage Japanese gear.

Well I found this totally fascinating. I have a Juno-106 which I sent to a local synth repair shop where they replaced the voice chips (because mine had the faulty Roland voice chips) and then about 12 months later, the Chorus selection failed to operate. They fixed that too and restored the factory patches (which had disappeared - I don't know what caused that). But now they have told me they won't be repairing any more old Junos because they're too hard to work on. This is partly why I found your video so interesting. Maybe I can learn about electronics so that if my beloved Juno-106 develops another fault, I might be able to fix it myself.

Your knowledge and excellent explanations have me returning to your channel over and over. For years I've imagined how cool it would be to understand how how electronic systems work and here you are taking the time and energy to make these great videos; videos that are educational AND entertaining. Thank you so much for what you're doing here!

Brilliant video.

I am 1 of those 2 people you talked about at the beginning of video. Thank you!

Your videos are always wonderfully educational, thanks for all the detail on how the pieces work!

I will wait for the second part of this very interesting repair! Thanks for sharing

Thank you again for the details! Keep em coming. Enjoying learning.

Nice! I love your desoldering tool. I need to add that to my tool "want" list...

Thank you, great stuff yet again. I have a Casio CZ-5000 that gets similarly stuck at boot up. The CZ also uses a 7811, so the pointers you gave here will help me check if it's the CPU that's failed. And if it is... I don't think the Casio will work very well as a coffee table or an anchor either.

I remember a time I could read the little codes on tiny ceramic caps and transistor labels. Now I need reading glasses, magnification, plus tons of light. So frustrating.

great video!

Ohh man, you are lifesaver, I have an early Juno 106 with the external PROM as you mentioned, I was trying to get new CPU put never found one on Ebay, now I will need to check my CPU as you mentioned. Thanks

I replaced the filter chips in my Juno 106, although it was kind of fun to play it with the failing chips because I never knew what a note was going to sound like. Now the pitch bender has stopped working and I just don't like it enough to fix it.

Looked at a PDF of the service manual… I love your content, but censoring the word “Master” is a bit overkill…

You are a wizard!!!

Your videos are great pls Keep making them

Mother and Daughter board??? whats wrong with those terms? world has gone doped out! Great video - smart man!! :)

Excellent video on troubleshooting the CPU. I have a 106 I saved from a dumpster. After working on it on/off for months, I have it working fairly well and all the boards were cleaned serviced and look factory new. The BIG question is the blue key caps for the voice patches. Has anyone ever figured out a way to make them blue again from solar fade?

Nice video as always.. thanks!!

Amazing

I just did the standard voice chip swap on a Juno 106 and the amount of flux residue on those boards is incredible. Isn't that bad for the longevity of the PCB?

Cool!

Could you also have tried the upd7811 with the external rom (with the mode pin strapping set to external), just in case the cpu was ok but the mask rom portion faulty?

I’ve got a rare Roland U20, with a dead keyboard. I don’t suppose you fancy making a video about that and helping me fix it?

whats the 'frowned upon terminology'?

good job, one question, my synthesizer (Akai AX80) turns off some keys when I'm with polyphony but when I choose it other presets are heard, and it turns off other different keys, this is with polyphony but without it all the keys work, unfortunately I find myself in another country to go see you at your workshop, could you give me an idea?

is there a what happens next?

Haha.... I love the sarcy CPU dig at the politically-correct-wokester-mob... 🤣

64 pins lol

I know its 2 yrs on, but, juno's are pieces of shit. But i dont really mean that. They were not built to be the most revelled synth of all time. I have owned 2 and they both went south. 👎