Markbass Little Mark II

[Enzo]

The odd duck Fender Passport has always had an SMPS, and they used to document it. They also used to have us fix them. But later versions, they omit the SMPS schematic, and call the whole module a "part" and do expect us to replace the whole thing under warranty. I still repair the things component level even under warranty. But Fender told me they did that because for many if not most amp techs, the SMPS is out of their expertise, and also does not share many parts with amp circuits, so they bit the bullet.


I don;'t see SMPS as non-repairable, I just see it as a warranty replace only item. And the factory doesn't require or expect me to fix an SMPS, but is just as happy when I do.

Also, a lot of factories are now buying SMPS modules from a vendor. The vendor may not be interested in sharing his documents, and the factory may not be interested in stocking all the vendors parts, and so on.

[J M Fahey]

The point being missed here is that it is more and more common for the smps to be a non-repairable part. To the point where some new documentation does not include schematics for the smps sections.
I don't think replacing a whole smps is all that uncommon any more, but putting it on the same board as the rest of the amp just pushes the whole unit closer to being a disposable item (I guess the modern "spin" they put on that would be calling it recyclable).
There are apple laptops that do not have a replaceable battery. Out of warranty you toss it. I hate seeing amps going in that direction.

Fact is, 1 hour bench time costs between U$60 to U$125.
Official warranty shops sometimes get less, say U$45 fixed price unless they can *really* justify more in the eyes of the Factory (never easy).
So if that robot made board costs same or less to the Factory, it´s a no brainer that they will prefer straight replacement.

"Disposable" yet high quality very complex stuff , rather than a bleak future, means we have reached a Science Fiction era of cheap robotic production.

NOTE: the fact that they ask, say, $250 for an actual parts cost board of $40 or less is something else.

Although they are nor really selling you "the parts" but what they made with them.

Same way with, say, a Music CD

Nobody complains about this:



Ella Fitzgerald Sings The Cole Porter Songbook
Ella Fitzgerald Louis Armstrong
Format: Audio CD
Price: $23.23

*Factory* cost around $1 or $2 (including sleeve)
So if you got a defective one, they send another.
End of problem.

Now if, say, your dog destroys it, (not their problem), you´ll pay U$23.23 (plus postage) through the nose.

Same thing.

[hitch]

If I have two cd's, and my dog chews on one of them, this scheme means I have to pay the $23.23 to replace it. ... fine, a bit of a hose job, but such it is. however, if my dog chews both of them, I get to pay $46.46. same logic if I have an amp with discrete power and amp parts. but, when the two parts of my amp are on the same circuit board, I get to pay the "$46.46" fee, even if only the "$23.23" part broke. that is the issue that I am having. the only one who wins here is the manufacturer, in the short run. MB gets a larger profit on the same small item failure, which is probably a $5 dollar part. but I have a memory, and you can bet that I will not purchase another system that is "one-fail-replace-all" from that manufacturer.

[Enzo]

I think you miss Juan's point. A SMPS/amp board might sell for $200 but cost them far less. Do you really think the two boards would each cost only $100? The materials are not the major cost of a board. Chances are the result would be two different opportunities to charge $200.

Example, the Ella CD was $24. If they reissued the music and sold half the tunes on one CD and the other half of the tunes on a second CD, they would not sell the CDs at $12 each, they would both sell at the regular CD price of $24. Last time I shopped for CDs, they did not charge by the number of songs on them. I think that is closer to what would happen with two boards.


Another consideration occurs to me. Noise mission is an important aspect, and these modern SMPS and digital amplifier combination keep all that high frequency stuff in a tight little space, and likely a lot easier to meet FCC noise specs than spread out designs. Or that could be a non-issue.

[J M Fahey]

Consider it a 2 CD boxed/special/whatever edition.

Even if physically separate, they sell as a unit.

If your dogs chews one (don´t ask me why I repeat this example ) I very much doubt the Company will sell you just the one missing for half price, even if you tell them: "hey !!! don´t worry about packaging!! , I just want the CD, a plain brown envelope will be fine !!!"

But way beyond analogies, tons of Guitar Amps (that includes Bass ) come in "one large board holds *everything* " versions only.

In most cases with old, large components, they are "repairable" ; today many are not.

Even in non Electronic but "mechanical" stuff.

Here in Argentina it still pays to recone "cheap" OEM speakers, such as Blue Marvels or generic "house brand" ones, mainly because ordering a replacement requires transfering Pesos into Dollars, paying Air Freight, going to the Customs office to fill paperwork and pay some fee, etc, so people don´t want to go through that, but in USA hundreds or thousands of good speakers (think Eminence, modern Jensen and some Celestions) are being junked.

Yet in many cases it´s a dead $2 voice coil .... but it requires you to do a full recone, so most people buy a new one and call it a day.

What worries me much more is that SMPS+digital amps are still evolving, what means that last year products are already obsolete and in a couple years neither spare controller ICs not even full boards will be available.

Same is happening here with much lower technology power ICs, both integrated and hybrid.

Very popular TDA1514 is long out of production, same with many STK modules.

Last month I helped a colleague repair a Kustom Bass amplifier with a 120W module which is unavailable here ... luckily the 140W has same size and , above all, pinout and he got 2 (he bought the other one at the shop just in case).

In many amps with similar problems or with torched-hole/crater-in-PCB syndrome, I just junk it (or cut part of the PCB with a Dremel wheel) and somehow mount one of my own .

Customers (different from USA) never complain , they are happy to have their amp back.

[hitch]

an update re the repair of a faulty MarkBass II

the repair depot that was recommended by markbass has found that several transistors in the switching power supply have shorted out. the technician is recommending that, due to the domino effect of failing components, the power supply is probably damaged beyond these components. therefore the whole power supply needs replacing. ... due to the power supply being on the same board as the amp, the whole board has to be replaced. therefore, the repair cost is $400 plus tax.

a totally new markbass little mark III is only $695 at a quality U.S. site. so, I am very upset that my three year old amp has a pending repair bill of over 50% of its replacement cost, due to the failure of a few items in a power supply that is integrated with the amp. I'd have to think that replacing ONLY a power supply in a unit that separated the two items would probably be in the $225 range.

I am actively checking out other brands, as an alternative to supporting this design flaw.

[g1]

Maybe check with Markbass directly, whether their intention was that entire amp boards be replaced when SMPS fails. They may want to have a word with this particular repair depot, or rethink their manufacturing strategy.

[MarkusBass]

the repair depot that was recommended by markbass has found that several transistors in the switching power supply have shorted out. the technician is recommending that, due to the domino effect of failing components, the power supply is probably damaged beyond these components. therefore the whole power supply needs replacing. ... due to the power supply being on the same board as the amp, the whole board has to be replaced. therefore, the repair cost is $400 plus tax.

This is not a problem with Markbass. It's rather a problem with poorly qualified repair centre. If you'd lived in Poland, the amp would be fixed for I think less than $200. The only condition is that the PC board is not burnt. I fixed several Markbass amps as this is not that difficult. Maybe you should look for a better service depot?

Mark

[g1]

That's what I was hinting at Markus, best that they know about it.

[Justin Thomas]

I would bet he cost of the whole amp board vs. a board w. just the power supply would be marginal. I'm with g-one - contact Markbass. They may want to know. At least try. And as MarkusBass said - poorly qualified repair center, or my own opinion, charging way too much. But if I was a manufacturer, I wouldn't want my customers getting stuck like that. $450 repair or $700 new? Heck, that's almost DNR territory to me... Best to find out and let the mfr know.

Justin

[MarkusBass]

And as MarkusBass said - poorly qualified repair center, or my own opinion, charging way too much.

They are not charging too much. They are simply not able to fix the amp (they don't have sufficient knowledge to do it) and they only can offer replacing the board with a new one (and $400 may be a real price of the module imported from Italy). Maybe Enzo, or Stan will be able to add their opinions. I think that this is typical policy of many manufacturers: don't spend time on fixing an amp, just replace the module that failed. In many cases this is a good policy but they didn't foreseen situation when the cost of a module is almost the same as the cost of the amp. This usually leads to customers turning to other manufacturers (who do exactly the same). The solution is simple; instead of trying to fix the amp with recommended by Markbass service centre, go to a local workshop that has experience with this brand. It's hard to believe that you cannot find such a workshop in the US.

Mark

[hitch]

I will follow up with markbass. but simply the fact that I need to be pursuing this path is really too much. if these machines are sold as "good quality" (and the pricing is in the "good quality" range), I expect fair treatment. so far I do not see it that way. and, to be sure, the board did not show any burn marks prior to going in to the depot, and it was not popping fuses.

[MarkusBass]

I will follow up with markbass. but simply the fact that I need to be pursuing this path is really too much. if these machines are sold as "good quality" (and the pricing is in the "good quality" range), I expect fair treatment. so far I do not see it that way. and, to be sure, the board did not show any burn marks prior to going in to the depot, and it was not popping fuses.

I would inform Markbass about the situation. Most probably they will answer that the amp has to be fixed by an authorized service centre, the cost of the module is $300 and the rest is labour of the service. But you may let them know that you are not happy with this situation.
The fact that the board is not burnt means that there is a big chance that it can be easily fixed. Where exactly are you located? I think that there are guys here from NY that most probably could fix it. Alternatively come to Poland and I will fix it for you .
Fixing such an amp is (in general) difficult because amps are more and more complex, fixing them requires more knowledge, better tools and so on. Manufacturers should be interested in supporting their products but, as you can see, sometimes they are not. Turning to another amp brands may be a good sign for them (they may learn something).

Enzo, I need your support here .

Mark

[g1]

Markus, you are referring to the entire amp board as a module. As far as I know, there is only the one board, so it is not really a module at all, it is everything (I'm speculating, maybe there's a preamp board too?).
This is what Hitch complained of from the beginning, why ISN'T the SMPS it's own separate module? The fact that it is not leads me to believe they expect the SMPS will most often be repairable, unless the board itself is burnt beyond repair.
So they need to know if their service centres are not repairing at a component level.

[Enzo]

The whole distinction between power supply and amp is artificial, they are all one thing. Just because many amps have segmented the functions doesn;t remove their intimate relation. WHy stop there? In a push pull amp, why not have separate push and pull side boards? And the SMPS? Ought not that be divided into primary side circuits - the switcher - and the secondary side supplies? Usually only one side has a problem. Or perhaps low voltage and high voltage on different boards? because really, it is very rare that both high and low voltage supplies fail at the same time.

Look at discrete units out there. We have connectors between the sections failing, we are now dealing with very high frequencies, so board layout is MUCH more critical than it would be with a linear supply.

We often look at things through out own glasses. Servicability is certainly important, but so is proper operation and reliability. The engineers are expecting the vast majority of these to work trouble free long term. And I suspect they will.

This board takes power from the mains and sends it to a speaker. That is its function. we might want it to be split up so we can concentrate a bad part on a smaller surface. And we might really only be rationalizing ways to pay less. But it is still just one big circuit to convert power from one form to another. The desire to separate the left hand from the right is a human conceit.