#98 - Roland V-Accordion FR-7x repair

The instrument did not have sound through the speakers. The problem was diagnosed to be in the power supply of the amplifier. A step-down converter chip by Linear Technology has failed. The chip was replaced, and the accordion is back in business.
LT3693 datasheet: www.analog.com...
Renesas M61571AFP datasheet: docs.rs-online...

[@TestEquipmentAnonymous]

An accordion is an unexpected item on the channel and a well-executed diagnosis and repair. Always great to see earlier-repaired test equipment participating on the bench, too. Keep up the great work and the variety of devices under investigation is always enjoyable.

[@jameslawlor1635]

What an incredible gentleman..How could any person in the whole world be so knowledgeable. I watched in awesome wonder. Amazing, Thanks...

[@Stephen_Heathcote]

Another excellent upload! Keeps me sane and 3 in quick succession :)

[@largepimping]

Heh... after hours of very complex troubleshooting, "No problem at all, it is working." Understatement level: British. Loved it, please keep the repairs coming. And it baffles me how this channel does not have more subscribers - maybe youtoob'z big data algos don't know everything after all.

[@laser-on-off]

This channel deserves much more subscribers and likes. Thanks again for this excellent repair.

[@Discretesignals]

I admire your diagnostic skills and knowledge. Great job!

[@jacektumilowski1003]

An excellent troubleshooting and its results. You are genius.

[@Praveen-lu9tw]

ossm job! love watching you debug and fix things

[@andymouse]

Great diagnostics !

[@TheDefpom]

Interesting repair and instrument, my brother used to play the accordion, he used to go busking and play it on the streets, I don’t think he has played for about 10 years now.

[@TonyBarr99]

Excellent repair. Educational and entertaining.

[@DrFrank-xj9bc]

Nice and interesting repair on a very special instrument. I expected, that you would have tested it by performing a piece of Russian folk music. 🎵🎵🎵😀

[@amirb715]

excellent methodical repair as always. thanks

[@vincei4252]

Excellent repair! Thanks for sharing.

[@michaelmcguinness647]

fantastic videos, do FR7s have over voltage protection within the accordion via relays or fuses.

[@jovangrbic97]

@FeedbackLoop At 13:03 you measure the resistance across a capacitor in circuit (cap across rail) in order to ascertain current draw. Can you explain this technique please? What does high/low resistance in this situation correspond to as to current draw?

[@feedback-loop]

Just a crude check to make sure there is no short or close to a short, which might cause the supply to not start or something.

[@jovangrbic97]

@@feedback-loop But is the resistance measurement not wholly biased by the 1.9V across the cap as it is powered? Or was this done at an unpowered state, because I see the wired hooked up... In the latter that makes sense. I just though there was some magic trick with a powered circuit...

[@feedback-loop]

I think I said that I turned it off.

[@jovangrbic97]

@@feedback-loop AH that makes much more sense now thanks! Just one last question, in the 21V regulator section, there is in the top left a 47uH (470) inductor marked L2, and in the bottom right, thoe one you said you lifted and where you place the red wire for measuring the voltage, marked L19. In the LT3693 datasheet it only specs one inductor, I expect this is L2. What is the purpose of L19 (the big black square one you lifted)? Just filtration? (what value is it roughly, I don't see a marking) Thanks!

[@feedback-loop]

Just a filter on the output I think, a choke to block the switching frequency from going to the amplifier. It has two coils: one for the ground, and another for the 21 V rail.

[@oldblokeh]

Nice repair. Do you think it might have been a good idea to use some foil/kapton tape to protect the electrolytics from the hot air? My wife asks: "What is the difference beteween an accordion and a trampoline? Answer: you take your shoes off before jumping up and down on a trampoline." :)

[@feedback-loop]

Perhaps, but I doubt it would make a huge difference. They would get hot through the board anyway.

[@oldblokeh]

@@feedback-loop I've been hit in the face by one of these little SMD electrolytics that let go under very similar circumstances to your repair, so I'm always more careful now. Oddly enough, that was in a Roland, synth.

[@ronaldfegan4834]

I have a problem with my Left (Mono) output jack. There is no sound. I now know, thanks to you, that the Right and Left output jack do the same thing. I'd still like to fix this problem. Is there a website that lists the FR7X parts. I can't find one online.

[@feedback-loop]

this looks right on the first glance: www.ebay.com/itm/Pioneer-Replacement-Audio-JACK-1-4-3-Pin-1-Piece-No-Washer/142671745858

[@DiegoooTech]

Thanks as always. I like to look at capacitors in input and output stage of power rails. I'l remember that. Noob here :D Thumbs up.

[@extra2743]

Sir what is the replacement part called ? Thanks

[@feedback-loop]

@12:22 - step-down switching regulator LT3693 by Linear Technology

[@RambozoClown]

It appeared as though there wasn't enough solder on the center heatsinking pad to fully bond the old chip. Do you think that might have been the cause of the failure? Great troubleshooting video. I can always pick up a tip or two in every one.

[@feedback-loop]

Looked fine to me. The pad on the chip is about the size of that solder blob. I should have shown the other side of the chip.

[@adidemeter5816]

Hello, can someone help me with a wiring diagram. I want to mount directly on the accordion case a midi plug aut.eu I have a v-accordion fr7 .thanks

[@eduardoeirasneto2373]

Please my friend. I am from Brasil. I have a Roland Fr3x, and it have a problem. When I turn on it the display Stay Flashing and nothing more work. Can you tell me what is the problem with my instrument.? Thank you...

[@mromar355]

Sir I have a Roland FR-7 that was recently given to me. Some of the keys are not working. I have watched some videos of people cleaning the key contacts (carbon sensors). Have you come across this problem with a Roland accordion Sir? And how do you go about it? Thank you!

[@extra2743]

The replacement thing , you call "the culprit" does it have a name? What is it a diode, transistor? , capacitor? What is it?

[@feedback-loop]

@12:11

[@mihaipiu4061]

Bună ziua! Am acordeon Roland Fr.8X și când îi dau drumul restartează continuu,ce problemă ar fi vă frumos? Multumim frumos! Aștept un telefon!

[@octavmandru9219]

I would have never guessed an accordion can be so complex. For sure, not many could have get it fixed properly

[@xDevscom_EE]

I would remove electrolytic capacitor before applying hot air, to avoid stressing it with heat. Also I am surprised to see so nicely designed PCB inside the musical instrument. Very impressed.

[@feedback-loop]

Yes, I do understand these concerns about the electrolytic caps. There are always some trade-offs. There is some stress in removing them and putting back, and a lot more work. And they have been oven-reflowed in the first place (yes, most probably with a better controlled temperature profile). Regarding nice PCBs, Roland is a very reputable shop.

[@xDevscom_EE]

@@feedback-loop I have zero experience with audio/music equipment, so forgive me my ignorance. Many server power supplies are designed worse than this Roland PSU :) Good job and thanks for sharing.

[@PapasDino]

@@feedback-loop I suppose a bit of Kapton tape masking off the area would reduce the thermal shock as well. Nice work as usual!

[@tonybell1597]

Excellent stuff, thanks. And a little hot air action thrown in for good measure, you usually dont bother with Soldering shots.. :-)

[@keppro]

Terrific work! I know for fact that Roland support don't bother to troubleshoot at nearly close level: they provide basic diagnostics and replace the whole mainboard...

[@feedback-loop]

I wish they shared the service manual. Schematics would help tremendously.

[@vajrasattva1]

A couple things: 1. I own an FR-8X model and last year one of the output jacks broke. It was interesting to see that someone had replaced just the jack on this. In my case, Roland sent an entire apparatus (I presume the jack and the small board it was attached to). It cost $45CAD and took three months to arrive. Ten minutes to replace. 2. I really don't know the first thing about electronics, but I was impressed by your ability to troubleshoot and pinpoint the problem without schematics.👍

[@feedback-loop]

@vajrasattva1 I don't know where the replacement jack I showed in the video came from, but my quick search came up with this: www.ebay.com/itm/Pioneer-Replacement-Audio-JACK-1-4-3-Pin-1-Piece-No-Washer/142671745858 Seems to be the right type (for FR-7x at least).

[@keppro]

@@feedback-loop The service manual is available, I can find it for you if you decided to continue this journey :) BTW, a lot of Roland V-Accordion owners would bless you if you do.

[@feedback-loop]

@@keppro Is it available? I spent some time looking for it before starting this repair. Where can I get one? Does it have schematics? Thanks.

[@malgailany]

What flux did you use (link if possible)? Very nice analysis. Thanks.

[@feedback-loop]

I am using MG Chemicals no clean paste: www.mgchemicals.com/products/solder-and-accessories/fluxes/no-clean-flux-paste-8341

[@malgailany]

@@feedback-loop Thank you!

[@garoin]

Dear Sir, I have a same model of the Roland Accordion FR-7X. The display unit of it has developed some lines. Can you manage a spare display unit of the same. If you can ship it to me, after receiving payment from me, it would be of great help. I am in India hence shipping of the whole unit is not possible. Please do let me know!

[@extra2743]

So what are you,an electronic engineer? Please let me know. Thanks

[@feedback-loop]

software engineer :)

[@RAFAIMAXIMVIDEOJUEGOS]

Hola .tengo un roland fr7 y se queda parpadeando ..tiene solución? Me podrías dejar un número de teléfono y hablar ?

[@ljubomirculibrk4097]

It has as big board as it gets, nuts, its a acordian :))

[@ydonl]

New theme music, maybe? :)

[@douro20]

This thing costs more than a real accordion! I would imagine it sounds better through a good acoustic amp than through the internal speakers.

[@MerlinMerlinL]

wow

[@anthonyflint7419]

Oh my god please let me have no problems. 🙏🙏🙏 My fr7 footpedal fbc charger is powerless. Sent it into roland. 🙏

[@anthonyflint7419]

You could do a university degree in electronics on this instrument. 🤢🤮