Markbass SD 800 circuit board

[BassSpinner]

Hey, hello, sorry to bother you bass friends, but I got this images. This is from a Markbass SD800 board. The first is the number of the Chip, hardly readable, the second is the Chip itself, the third is the position from where the Chip is. My question, could anyone can see if you can tell me the numbers of the Chip? Or, if it's not a lot, send me a picture of your circuit board with a legible part of the Chip? My technician is trying to get either the circuit specs or the Chip number so he can finish my amp. Thanks.

 

[60bass]

Have you Looked online for a schematic or contacted Mark Bass for one? That will tell you exactly what the part number is of that chip. If you can't locate one, it will help if you can tell us what part of the circuit the chip is from and how you decided it was bad? Class D amps are rarely able to be repaired without the schematic and test equipment. If that IC burned up what caused it? Markbass is known for not revealing certain details of their circuits. Wanting you to send the unit in for repair.

If that IC5 is part of the driver circuit for the MOSFETS at T22 and T23 it's quite possible that one or both went out and caused the failure of IC5. Again a schematic and testing of the circuit is needed. The last thing you want to do is replace that and have it fail too due to another part being bad. Which is highly likely.

TBH MarkBass and their lack of providing schematics or info when asked is the main reason I sold off my LMII and never looked back. I hope you can get this resolved.

If you haven't checked on the Markbass amp heads (long term users) thread here on TB, it may be of some help. A search of IC5 turned up these threads. It's regarding an LM II, but the power section which is where that IC seems to be from should be similar.

https://www.talkbass.com/threads/markbass-amp-heads-long-term-users.1122516/

https://www.talkbass.com/threads/markbass-amp-heads-long-term-users.1122516/page-2#post-16750018

https://www.talkbass.com/threads/markbass-amp-heads-long-term-users.1122516/page-2#post-16750988

 

[BassSpinner]

Have you Looked online for a schematic or contacted Mark Bass for one? That will tell you exactly what the part number is of that chip. If you can't locate one, it will help if you can tell us what part of the circuit the chip is from and how you decided it was bad? Class D amps are rarely able to be repaired without the schematic and test equipment. If that IC burned up what caused it? Markbass is known for not revealing certain details of their circuits. Wanting you to send the unit in for repair.

If that IC5 is part of the driver circuit for the MOSFETS at T22 and T23 it's quite possible that one or both went out and caused the failure of IC5. Again a schematic and testing of the circuit is needed. The last thing you want to do is replace that and have it fail too due to another part being bad. Which is highly likely.

TBH MarkBass and their lack of providing schematics or info when asked is the main reason I sold off my LMII and never looked back. I hope you can get this resolved.

If you haven't checked on the Markbass amp heads (long term users) thread here on TB, it may be of some help. A search of IC5 turned up these threads. It's regarding an LM II, but the power section which is where that IC seems to be from should be similar.

https://www.talkbass.com/threads/markbass-amp-heads-long-term-users.1122516/

https://www.talkbass.com/threads/markbass-amp-heads-long-term-users.1122516/page-2#post-16750018

https://www.talkbass.com/threads/markbass-amp-heads-long-term-users.1122516/page-2#post-16750988

Hey, hello, my technician wrote to them. He couldn't find the schematics on them. Thanks for the info.

 

[60bass]

Hey, hello, my technician wrote to them. He couldn't find the schematics on them. Thanks for the info.

I hope they provide him what he needs to repair your head.

 

[agedhorse]

There is a whole network of factory AUTHORIZED service centers. They have access to service documentation, parts and factory support. Non-authorized shops won’t have access because they haven’t made the commitment nor have they agreed to follow the factory service policies.

In the US, VST is the service center of record.

Mark Bass Repair Service Center, Mark Acoustic Repair Service Center

enter your site description here

www.vstservice.com

 

[BassSpinner]

There is a whole network of factory AUTHORIZED service centers. They have access to service documentation, parts and factory support. Non-authorized shops won’t have access because they haven’t made the commitment nor have they agreed to follow the factory service policies.

In the US, VST is the service center of record.

Mark Bass Repair Service Center, Mark Acoustic Repair Service Center

enter your site description here

www.vstservice.com

Hey, hello, I really appreciate this, thanks a lot.

 

[Boneless]

There is a whole network of factory AUTHORIZED service centers. They have access to service documentation, parts and factory support. Non-authorized shops won’t have access because they haven’t made the commitment nor have they agreed to follow the factory service policies.

In the US, VST is the service center of record.

Mark Bass Repair Service Center, Mark Acoustic Repair Service Center

enter your site description here

www.vstservice.com

Which goes against the right to repair. Oh well.

 

[groooooove]

There is a whole network of factory AUTHORIZED service centers. They have access to service documentation, parts and factory support. Non-authorized shops won’t have access because they haven’t made the commitment nor have they agreed to follow the factory service policies.

In the US, VST is the service center of record.

Mark Bass Repair Service Center, Mark Acoustic Repair Service Center

enter your site description here

www.vstservice.com

i've mentioned it a million times since it annoyed me so much, but a factory authorized service center told me there were zero parts available for this exact amp.

i contacted markbass 4 times and never heard a word back.

it is for this reason i no longer trust their products. yes, it's a 15 year old amp. but since when did a great sounding piece of gear only get a 15 year life span?

 

[agedhorse]

i've mentioned it a million times since it annoyed me so much, but a factory authorized service center told me there were zero parts available for this exact amp.

i contacted markbass 4 times and never heard a word back.

it is for this reason i no longer trust their products. yes, it's a 15 year old amp. but since when did a great sounding piece of gear only get a 15 year life span?

Did you contact VST? They handle all service related matters for MarkBass in the US.

Which goes against the right to repair. Oh well.

I agree if they no longer support the amp through their authorized service network, but there’s proprietary technology within their amps that they are entitled to protect as well, and they still use some of it in their new amps so they deserve protection of their IP too.

 

[BassSpinner]

Did you contact VST? They handle all service related matters for MarkBass in the US.


I agree if they no longer support the amp through their authorized service network, but there’s proprietary technology within their amps that they are entitled to protect as well, and they still use some of it in their new amps so they deserve protection of their IP too.

Hey, hello, thanks for all your help, no, I haven't contact VST, by any chance, do you have an email or site that I can contact them?

 

[BassSpinner]

Hey, hello, thanks for all your help, no, I haven't contact VST, by any chance, do you have an email or site that I can contact them?

Hey, hello, sorry, you already gave me the info.

 

[Engle]

i've mentioned it a million times since it annoyed me so much, but a factory authorized service center told me there were zero parts available for this exact amp.

i contacted markbass 4 times and never heard a word back.

it is for this reason i no longer trust their products. yes, it's a 15 year old amp. but since when did a great sounding piece of gear only get a 15 year life span?

Appliances are similar. They are more efficient than they used to be, but they don't last more than 10 years.

 

[groooooove]

Did you contact VST? They handle all service related matters for MarkBass in the US.

they are the ones who directed me to the authorized service center in NY, who diagnosed it as unrepairable/no parts have been available for years.

i tried everything because i loved how this amp worked and i had used it so much i did not want to move on.

i did actually hear from MB once. they responded when i tagged them on instagram, saying that the amplifier was deemed not fixable. they said "of course we can fix it! visit a service center!" - not surprisingly, i heard nothing back when i told them they just watched a video of my amp in the authorized service center, and that's who said it can't be fixed.

 

[agedhorse]

I generally recommend using VST as the service center.

 

[sokolasty]

I had a minor issue with my amp. Flimsy USB connector fell off. I paid 7$ which is here about one hour minimum wage to have it repaired. I walked to a cell phone repair guy 100 meters my home with the PCB disassembled. Official Fender repair shop starts at 100EUR plus shipping plus waiting.

Official authorized repair centers aren't perfect solution and that's the last place I go. They tend to cost plenty while repair service is average. And, as we can see in OP example, sometimes they can't do the job.

 

[agedhorse]

I had a minor issue with my amp. Flimsy USB connector fell off. I paid 7$ which is here about one hour minimum wage to have it repaired. I walked to a cell phone repair guy 100 meters my home with the PCB disassembled. Official Fender repair shop starts at 100EUR plus shipping plus waiting.

Official authorized repair centers aren't perfect solution and that's the last place I go. They tend to cost plenty while repair service is average. And, as we can see in OP example, sometimes they can't do the job.

In general I disagree, though there may be rare exceptions.

 

[Boneless]

I agree if they no longer support the amp through their authorized service network, but there’s proprietary technology within their amps that they are entitled to protect as well, and they still use some of it in their new amps so they deserve protection of their IP too.

Honestly, I've never bought this argument. We both know that if you really want to reverse engineer something you will do it. Not providing the schematics or scratching away markings is only going to inconvenience users (and repairers). Plus, this is not software and there are very material costs involved in copying/reproducing stuff (which are not really worth the trouble, by the way). Of course, if there is official servicing provided, then it does make sense to go through them first, but sometimes the quotations they give are hardly justified (instead of replacing a faulty device, they sell you the whole board). I mean, if it's a matter of protecting IP, then just coat the board in epoxy or something. At that point there is no way around it

 

[agedhorse]

Honestly, I've never bought this argument. We both know that if you really want to reverse engineer something you will do it. Not providing the schematics or scratching away markings is only going to inconvenience users (and repairers). Plus, this is not software and there are very material costs involved in copying/reproducing stuff (which are not really worth the trouble, by the way). Of course, if there is official servicing provided, then it does make sense to go through them first, but sometimes the quotations they give are hardly justified (instead of replacing a faulty device, they sell you the whole board). I mean, if it's a matter of protecting IP, then just coat the board in epoxy or something. At that point there is no way around it

You might have a different perspective if you ever had a design of yours stolen (“copied”) after investing and paying for the development. I have and it sucks.

 

[BassSpinner]

You might have a different perspective if you ever had a design of yours stolen (“copied”) after investing and paying for the development. I have and it sucks.

Hey, hello fellow bass players, I am really honored that you tried to help me with all this information, but at the same time I apologize for any inconvenience that it made you feel or imply in this post. It was not my intention. I respect every attempt to help me and other fellow musicians { or technicians} in the rescue and fixing of any type of electronics that, in any way, is important to you. All I can say is thank you. Hope that all together can resolve this and any bad circuit around. Have a wonderful day.