Roland D-Bass 210

[TomCarlos]

Friends...

The local high school brought me a Roland D-Bass 210 amp. It is DOA. Before I get any further, I thought I might check in with you all to see if anyone has any experience with these amps. Is it worth me spending time to troubleshoot or is this a known problem child and we move on to something else?

The amp chassis was a bear to remove. On the bottom side of the chassis, the case had a hole and the wires ran through there. Typically, that is not a problem But Nooooooooooooooo... Roland uses a rubber plug with lots of goop and removing the chassis was a definite chore.

I can see a cage for the power supply and another for the power amp. Again, before I go any further, I thought I would ask for divine guidance. The amp also uses a speaker that has some type of Optical Sensor on the speaker which provides feedback to the preamp and power amp.

Finding a schematic is tricky... you need to become a member of some web site and then you can download a manual etc etc etc. I don't know if Roland would respond to a query for a schematic. I'll try.

Thanks, Tom

[Jazz P Bass]

Highly doubtful that you will find a schematic online, as this is a fairly new unit.

One word: DIGITAL.

[TomCarlos]

I hear ya John !!

So... first things first... Power Supply... Blown T8AL fuse and BIG ASS cap was floating in space. It looks like either we have bad pins coming out of the cap or they simply broke off. There are some burn signs on the (+) lead, maybe arching? The cap measures 1968uf with 3.1 ohms ESR (using my atlas ESR meter). These are Nippon Chemi-Con 2200uf, 200V caps.

Everything else looks ok.

Stay tuned...

[Steve L]

Service Manual

I have the service manual for this.
It is too large to post here (6.7M), however you can send me your email and I will gladly send you a copy.

Steve

[TomCarlos]

Thanks Steve.... I will send an email ....

[TomCarlos]

I replaced the cap and fuse and this amp is still pulling lots of current. My bulb limiter is bright enough to shine my room. Anyway, this one might be a tad too complex for me. Thanks again Steve for sending me the service manual.

[Jazz P Bass]

Try to crop the schematic.

If it is not write protected you can use something like "Cute PDF Writer".

Or maybe scan the power supply & upload that.

[J M Fahey]

Not being too optimistic, but it "might" be easier than it looks.

The Digital area is way beyond my area but what you show is at the very front/beginning of the power supply chain which no matter how digital it becomes later, starts with a classic and humble diode bridge feeding a first reservoir cap ... exactly the area that shows damage.

I can't imagine and downstream accident which can blow a large cap, in that situation, out of the PCB.
A horrendous short would have blown the fuse and maybe the diode bridge, but not the capacitor, so I guess one leg cracked mechanically and the small electrical arc overheated and blew it off.

The raw unfiltered DC might have blown the PSU switcher which was not expecting that .

I would:
1) disconnect power supply from any load.
Pray it has no "power good signal" coming from the power amp which disables the PSU if not received within "x" seconds.
2) try to fire up the PSU itself, starting with the bulb limiter still in line.
If it still shines brightly, replace 8A fuse and try it straight in the outlet, it might not like Variacs or light bulbs but start normally if connected straight.
Of course it might blow the fuse in a second.
3) expose PSU innards and start checking for damaged power devices: main input bridge, switchers, secondary diodes, shorted secondary caps, etc.

or do 3 before 2 .

Well, just as a starter, post results and if possible, extract the related supply pages.

Even if "secured" , printing the page visible on screen using Cute PDF Writer generates a single page copy as a new unsecured PDF which can be posted here or you can use on it the (very seldom used) regular Adobe Acrobat "snapshot tool" which captures a selected part of the screen (you may drag it to catch an area larger than the screen) and paste it in any graphic package (I use IrfanView but guess even Paint will do) , then saving as any graphics format you like.

I usually prefer .gif or .png because .jpg is fuzzy on small details.

On such a graphic you can write notes, modify it, add lines or symbols, etc. like on any other .gif or .png .

Notice that I don't even *mention* the digital area on which I have no clue.
3)

[TomCarlos]

Thanks JP and JM...

I will give your suggestions a try next week and report back.

Tom

[g1]

Even if "secured" , printing the page visible on screen using Cute PDF Writer generates a single page copy as a new unsecured PDF which can be posted here or you can use on it the (very seldom used) regular Adobe Acrobat "snapshot tool" which captures a selected part of the screen (you may drag it to catch an area larger than the screen) and paste it in any graphic package (I use IrfanView but guess even Paint will do) , then saving as any graphics format you like.

For quick & dirty, I just hit the "prt scrn" (print screen) button. Then "paste" into whatever simple graphics program (paint for windows).

[TomCarlos]

The Roland Service Manual contains pages for the 210 and 115 models. I have extracted pages for the 210.

On page 41, you will see a box for the incoming AC (lower left) but I cannot find the details for the fuse, 2200uf cap, etc.

If anyone wants the full service manual, please send me a Private Message with your email addy. The file is 5.6MB.

@ Juan - I will disconnect the PS from the main board and retest. This amp has "cages" protecting the PS and Main Amp so it will require some disasembly - I will get to it this week.

Thanks for the encouragement.

Tom

[jesusm1]

hi to all

i'm newbie on this forum and since this chat talks about a Roland D-Bass210 regarding a problem, i will let you another case to see if anyone could me on this

first, thanks Steve L. for the manual

second. i got this amp on where the Main board is not responding at all. the unit does not turn on but the board receives the PS voltages and also regulates the logic voltages to the CPU and DSP chips. i dont know if someone have been goes deep on this kind of repair, but since i have some knowledge on digital repair I performed the following analisys

the main chips (DSP ans CPU) are receiving the voltages and their crystals oscillators are oscillating. the reset from these chips are disabled but i dont see any data coming out from the CPU. i could assure the CPU (HD64F36049G) is the problem but i want to know if somebody instead of replace the whole board, could fix it

regards
Jesus

[z31rm]

Roland D-baSS 115 PROBLEM

Thanks JP and JM...

I will give your suggestions a try next week and report back.

Tom

Hi Carlos!

I wonder if you have fixed your faulty D-115?
I have one with seriously damaged PSU AND bass power amplifier , one section of it.
Bought Service manual from Canada seller on ebay ,but PSU as well as Power amps are only empty boxes , no electric diagram of them.
Have you , by chance , electronic diagram-schematics of these units?
That might help me solve problem.
Thank's' in advance.
Todor , Macedonia

[TomCarlos]

Hello Todor.... Welcome to MEF.

I was unable to repair the Roland Amp. It was for a local school and they decided not to spend any money for parts.

I have the schematic. I sent you a Private Message. Please reply there.

Tom Carlos

[z31rm]

Hello Todor.... Welcome to MEF.

I was unable to repair the Roland Amp. It was for a local school and they decided not to spend any money for parts.

I have the schematic. I sent you a Private Message. Please reply there.

Tom Carlos

It is

z31rm(at)mt.net.mk