Roland Cube Monitor CM-30

baldy

I have the above which has a snapped off male plug stuck in the right aux in socket.
How the hell do you get the back panel off ?
I have removed all the retaining screws & the panel will move a few mm off the back of the cabinet but it is still clearly being held on by something & I am afraid to force it any more for fear of damaging something.
What have I missed or is there some trick to getting the back panel off ?

baldy

No one ?
I was hoping that someone like ICBM  might have some suggestions.
I have also tried to get at the socket from the front by removing the grill & speaker but there are components in the way which are attached from the rear so that didn"t work.
I have emailed Roland"s tech support but their advice is to take/send it to a Roland dealer or the Roland repair centre.
It is only a snapped plug & if I could get the back off it should be straight forward to get the piece out of the input socket.

545454

Not sure if this is relevant for the Cm60 given the design, but I opened up a Cube 60 recently - once the screws were out, I had to loosen some sticky tape stuff that was securing the chassis to the cabinet. Gently ran a thin blunt knife all the way round - can send you pics if you like as i'm not describing it well! Even then, it was a bit stubborn to get it moving initially...

ICBM

I haven’t taken one of these apart. Are there any bolts in the bottom? Possibly under any of the plastic trim, or the feet - or inside the recess for the handle? Some amps like this have very non-obvious bolts... they’re not really expected to be taken apart, so the order of assembly isn’t necessarily logical for servicing.

Depending on the type of jack it isn’t a certainty you’ll be able to get at it even from the inside either - Roland usually use ‘box’ jacks which you can’t get into.

baldy

Thanks for the replies.
There are 10 machine bolts holding the back panel on (nothing underneath or on top).
When you remove them the panel will come away from the cabinet freely maybe 5-8mm but no more.
It definitely doesen"t feel like it is still being held on with a fixing but rather wires if that makes sense which is why I am afraid to force it.
The speaker was held on by screws & sticky tape stuff, which I had to gently lever off but there is no sticky tape holding the back panel on.
If I can"t get the broken plug tip out then soldering on a new input would not be a problem for me providing I can gain access.

ICBM

That's possible. If it's like the Roland D-Bass amp I worked on a few months ago there may be a bundle of wires going through a hole in the cabinet to the space containing the speaker (and possibly power transformer). The hole and the wires were thoroughly glued up leaving only a very small amount of slack, which made removing the chassis extremely difficult without doing a lot of damage.

If so I would look at other ways of getting the broken plug out - how much is left in the jack, the whole shaft or just the tip?

baldy

The plug was fully in the input & has snapped off 4mm in from being flush with the outside of the socket if that makes sense.

Danny1969

You might find the amp is built on the panel and there's only a short amount of speaker wire going to the speaker so you might need to go in the front, remove speaker and unplug wire, then remove back panel. 

Personally I always just drill broken jacks out using a dremel and very small drill bit. In my world (laptops, iPads, Playstation controllers) everything 3.5mm so a bit more fiddly, larger broken jacks in sockets are a lot easier 

baldy

I had wondered if I could drill a pilot hole, screw in a small screw & use that to pull the broken part out.

baldy

Danny1969 said:

You might find the amp is built on the panel and there's only a short amount of speaker wire going to the speaker so you might need to go in the front, remove speaker and unplug wire, then remove back panel. 

Personally I always just drill broken jacks out using a dremel and very small drill bit. In my world (laptops, iPads, Playstation controllers) everything 3.5mm so a bit more fiddly, larger broken jacks in sockets are a lot easier 

I have gone in from the front & it is not that which is stopping the back panel coming away.

ICBM

That sounds like it shouldn't be impossible to pull the plug out - it's if the tip has broken off and turned sideways inside the jack that it's difficult.

If the broken jack has a tip 'rod' which is a tube - many cheaper ones do - you may be able to thread a very small self-tapping screw directly into it. If not, you'll need to drill.

baldy

Great advice ICBM, the offending broken plug is now out.
I drilled a pilot hole down the centre of the snapped off plug (plastic centre) then put a very small screw in a few turns & pulled the screw out drawing out the metal outer & what was left of the inner plastic of the broken plug.
Thanks again 

ICBM

Excellent . If it's built like that bass amp, getting it apart may have proved almost impossible without causing yourself so much trouble that you would wonder if it was worth it.

You wouldn't believe how little it can take to write off some - even quite good - modern amps as being uneconomical to repair, because of the way they're built...

baldy

Yes I had already spent a couple of hours trying to get at the back side of that aux in socket by various ways & had got nowhere.
Your description of bundles of wires glued into holes  " there may be a bundle of wires going through a hole in the cabinet to the space containing the speaker " is exactly what the resistance to getting the back panel off felt like to me.
The monitor seems to be quite well made but it seems that no provision for disassembling for repairs had been factored in to the build.

ICBM

I will admit I gave up on the D-Bass without trying very hard - there wasn't even enough slack to pull the chassis out and cut the wires, to be later (laboriously) replaced, let alone actually work on anything. Give that it had died in what was likely to be an expensive and hard to fix way anyway - either a switch mode power supply or Class D output section failure, most likely - I told the unfortunate owner to just take it to a Roland dealer and let them have the fun of it...