Roland Jupiter 4 JP-4 Repair - Synthchaser

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In this video we have a look around inside the mighty Roland JP-4 synthesizer and see how it works. Then we troubleshoot and repair this dead Jupiter 4.
00:39 - The Problem: No Output
01:28 - Tour Inside / Technical Overview
06:10 - Power Suppy Check
07:04 - CPU Check
11:56 - Key Assigner Board Check
13:30 - Main Motherboard Check
16:07 - DAC Troubleshooting
20:25 - Making The Repair
22:46 - Jupiter 4 Repaired!
Parts, service and synthesizers available on my website. I buy broken synthesizers!

[@TheMilford]

Japanese synths from this era are total art inside. The inside of my Yamaha CS-15 is insanely well-designed, The repair manual is also a thing of beauty.

[@PATRIK67KALLBACK]

Nice and quick fail seeking video! I hope you recorded the rest of the repair, it's ASMR for the eyes to watch professional repair and restauration.

[@AdamTheAd-vanc3d]

Man some of the stuff I didnt fully understand but boy was it super intresting :-)

[@thepthepthep]

BTW, another thing to keep an eye out for on the JP-4 is the 7805 regulator, the one in my JP-4 became faulty and caused the entire 5V rail to drop out after like 10 minutes or so. Just replaced it recently and all is well again

[@jebeq2007]

Your electronics synth knowledge is invaluable. I have a Roland VP-330 and the release on it works randomly but mostly does not work and is always at full release. I wish you were closer to me so I could bring it by for service.

[@dougpolkinghorne7884]

Your videos are always great and this is no exception. I like the new band name "Fluxy Residues". And then there's the "Lylac Matsushita Capacitor Band".

[@subs4794]

Hard to miss that diss of Moog and Arp polysynth designers ;) 06:00

[@nadersharif]

Thank you for sharing this video. It's always a pleasure to watch your work. Hopefully you can share Korg Trident Mk2 please.

[@andrewgarley1400]

Enjoyable, happy to carry on watching part 2

[@alphabeets]

Superb job on this video. Excellent presentation.

[@michaelvollmers9723]

Super Video, Klasse erklärt. Grüße Michael

[@MusicoElectronico]

Top notch job... as always from synth chaser 👍🏼👍🏼👍🏼

[@user-rv8wb1nl1b]

yay , great fix !

[@chriswatson2407]

Your musical talent know no bounds.

[@Synthchaser]

Haha! I accept my limitations.

[@SacSynths_Jack_Z]

Fantastic video! Really great walk through. Would love to see the voice card repair! Regardless, thank you!

[@Synthchaser]

That turned out to be boring--someone just hadn't seated the card all the way! I noticed it when I took the cards out to replace the lilac caps, one wasn't in there all the way.

[@SacSynths_Jack_Z]

@@Synthchaser Thx for the update!

[@user-rv8wb1nl1b]

are there any "mandatory " replacements inside a CS15 ? i had a filter chip wig out after using a sequencer . Its all better now (expensive YM chip though) . But if there are any tantalum or leaky things , please let me know . . . Love your channel , learning everyday !

[@retro-dademusic6403]

Awesome! 😎

[@SCOTTYD2031]

Love your work and high quality.

[@MusicMediccom]

You did a great job! This is very insightful!

[@toomuchtoofast4533]

Synthchaser! Nice work man! Best, Kyle OBXa.

[@Synthchaser]

Thanks!

[@johnhenderson4519]

I appreciate these videos. Thank you.

[@magicmastera]

You are amazing. Love that videos so much. Thanx.

[@mct_lima]

My JP4 has a dead voice, , I suspect it might be one of the VCA chips, is there a way of probing the chip in circuit? thanks

[@KarlA-vk4kn]

Great video 👏👏👏👍

[@Synthchaser]

Thank you 👍

[@orsat1]

Nice...nice...I have oldie JP4...it has been totally serviced by local technician...but problem appeared...output intensity changes periodically...have you any idea ? I would appreciated 👍

[@timosaruh9232]

Thank you for a great video! I got my hands on a JP-4, but am missing most screws for the top panel and also for the keybed and the controller section to be fixed from the bottom. Any tips on what kind of screws these are and where I can get these? Thanks in advance! 🤗🎹

[@thepthepthep]

According to the service manual, the four screws on the top panel are 4 x 8 mm truss head machine screws. The ones for the keybed and controller section are varied, there's four 4 x 60 mm oval machine screws and three 4 x 25 mm oval machine screws (which go in the very front). All of the bottom screws have dished washers.

[@jupitermarx]

What's the name of the device with the needle that your using to check power amps

[@samotbidotmusica]

Can u fix a roland jupiter xm?, need to replace all buttons, fall from 6 ft and lost almost all buttons, evrething else work fine

[@sP33DyEdOld]

Ow yeah I did mine in 2019. Adsr was gone on vcf had a bad cmos on the voice card controller board. What is your Version also the BA662? I added midi and This one Will never leave my studio 😉👍🏻

[@Synthchaser]

Lots of Yellow BA662s!

[@scottlarson1548]

It looks like it would be really hard to diagnose an individual voice card.

[@spinach1999]

What do you think of the Rigol DS1054 , I need a scope to fix stuff. Would you buy it again?

[@Synthchaser]

It's fine--does the job, has a lot of stuff my old higher bandwidth scope had but much quieter and more compact. I like it.

[@GNeuman]

Do you know Jareth?

[@jamesoneill6146]

Low volume ?