MarkBassChat

[quote name='alexisonfire' post='1075585' date='Jan 2 2011, 08:44 PM']The status light on the front panel is now flashing from red to green. The user manual does not specify what type of issue this warning represents. Before I take it to a tech, does anyone know what this could possibly be?[/quote]The problem is described in the user manual - page 4. What about the bias indicators on the back - are they green or red? Mark

Pete, Do you mean the switch on the back of the amp (see attachment)? It is a switch that switches several resistors in series with the horn. Most probably it was not contacting correctly. You can simply set it to minimum value. If you need, you can disconnect it but, as ICastle says, you should be sure that this is the only problem with the amp. I had exactly the same problem with rare TE 1225 combo. I had to replace the switch (and clean the board). Mark [attachment=67466:switch.jpg]

[quote name='WonderHorse' post='1062618' date='Dec 18 2010, 07:22 PM']I can't smell anything burning or owt - this is my first valve amp so I'm a bit stumped as to what it could be.[/quote]It's most probably a fuse. There is one fuse in the back of the amp; I think it's 6.3A (Slow-blow type). Often people use fast fuses which is not correct (and usually this causes problems like you have now). If it's not this fuse, there is another fuse inside the amp. I don't remember the exact value but it's something like 2A (also slow-blow type). To get to the inside fuse you need a screw-driver. Mark

[quote name='Dom in Somerset']I've had a chance to take a look inside, the wiring looks pristine, I suspect all original, this is a drawing of the jack: (my camera isn't up to the job)[/quote]Looks good although I don't understand what is the meaning of the question mark on the drawing . As Mart explained in[post="1050629"] post #4[/post] above testing the problem with a multimeter is simple. The problem can be caused by the battery connector shorted to the ground inside the jack (this also can be easily tested with a multimeter). If this is the case, you have to replace the jack. Mark

On the photos above I don't see a point where the preamp ground is connected to the copper shielding. I assume it is somewhere connected, isn't it? Mark

[quote name='silddx' post='1051079' date='Dec 8 2010, 12:49 AM']I think it's wired incorrectly. Can't remember what, but people on here have had the same issue installing onboard preamps incorrectly. Get a techie to look at it. There should be no battery consumption if there is no jack plugged in. A decent battery (I only use Duracell Procell) should last a few hundred hours.[/quote]Yes, this is exactly this case. The rule is simple: no jack plugged in -> no battery consumption. Mart explained how the problem should be solved. The preamp should not be connected to ground but to jack's third conductor that is connected to the ground only when a jack is plugged in. Mark

Yes, you need 40W with electronic circuit for the temperature control. The circuit does not have to be digital - analog is also OK. Mark

[quote name='JeSuisSkeleton']I posted a photo of the solder on TalkBass and someone told me that it's the original board (it says SR 3EQ or something similar).[/quote]OK, but this does not prove anything. He could replace an original board with another original board. [quote name='JeSuisSkeleton']I mean, I know nothing about electronics but the re-soldering just looks really messy.[/quote]Actually the board does not look that bad. It just looks like some unexperienced person did not know how to fix it and he resoldered everything (I never do that unless I know exactly what is the problem) and afterwards he forgot to clean the board. There still may be some cold solder joints but this is not a problem. It does not look nice but still can be fixed (and cleaned). [quote name='JeSuisSkeleton']I've been considering selling this and buying a new 'Ray if I can't get it back to how it was.[/quote]It's not a good idea. Fixing this preamp is easy but if you try to sell it without fixing the preamp first, you will loose a lot of money. Mark

This preamp is very simple, can be easily fixed and I cannot imagine that it costed more than e.g. £30 (no matter what was wrong with it). How do you know that it was not replaced? Usually in such cases I don't suspect preamp but rather wires (bad soldering), pickup switch, pots, output jack or battery. Mark

Can you post a photo of the preamp (components side)? I most cases fixing such preamp is quite easy. I wouldn't think of a new preamp until I'm sure that this one cannot be fixed. Regarding the neck I think that this is just a metter of one visit to a good luthier. Maybe you are not adjusting it correctly. Also if you are sure that the board was not replaced, can you tell us the name of the shop? Mark

The problem may be caused by several issues but I would never consider [quote name='MoonBassAlpha']... an odd failure mode with a cap across the supply rails[/quote]before I analyse typical possible causes. And if you have: [quote name='MoonBassAlpha']sound coming out of it all the time, punctuated fairly frequently by louder pops[/quote] this may be caused by failing capacitor in the signal path. So I would look at the power amp input capacitor and other small capacitors in the signal path (there are only 3 or 4 in this amp). Of course by "lookig at" I mean replacing them because the failure is usually not visible. If this does not help, I would look at the power supply. Mark

You can buy such pickups in several shops. For example here: [url="http://www.learnguitarshredding.com/2010/10/artec-giovanni-wcnb-wood-custom-bass-pickup-humbucker/"]http://www.learnguitarshredding.com/2010/1...ckup-humbucker/[/url] Mark

You mean this one: [url="http://uk.farnell.com/sanyo/2sd600ke/transistor-npn-120v-1a-to-126/dp/1790325?Ntt=1790325"]http://uk.farnell.com/sanyo/2sd600ke/trans...325?Ntt=1790325[/url] Regarding the first one; isn't it the Korean version of 2SD2059 ? [url="http://www.alldatasheet.com/datasheet-pdf/pdf/69925/KEC/KTD2059.html"]http://www.alldatasheet.com/datasheet-pdf/...EC/KTD2059.html[/url] - this one? This is a general purpose 30W NPN transistor. If you can't find exactly this one, there are replacements available. For example 2SD1407 (and many others). Mark

Nik, GK 700rb-II has only one internal fuse. Older version of this amp had 4 additional (also internal) fuses. But you have version II, right? The fuse is located on the left of the power cord socket (inside the amp). And it is not always visible that it is popped. How did you verify that it is OK? Also verify that the fuse is of T(slow) type and not F(fast). The value, as far as I remember, is 3.15A for UK. If this is not the fuse and not the power cable, you have to send the amp to a service. When checking the fuse disconnect the amp from mains power supply. Mark

[quote name='BurritoBass' post='1017845' date='Nov 9 2010, 07:53 PM']I plugged it in for soundcheck and there was an almighty bang. The cab and cables were all fine. I now get an intermittent signal with the bass sounding quieter, the bass sounding like a flanger is plugged in and the volume going up and down but much quieter than it should be.[/quote]I'm not sure about "flanger like sound" but usually "an almighty bang" means problems with output transistors. What amp is it? In some amps there are integrated circuits that are cheap, and in some amps (e.g. old Trace-Elliot or Marshall) there are hard to get and expensive transistors. So what is the brand of the amp and what is the power?[quote name='BurritoBass' post='1017845' date='Nov 9 2010, 07:53 PM']It was my second head as I mainly use a vintage valve head but this is / was good for smaller gigs. My friend who knows a bit seemed to think it might be a dry joint? Either way it's 15yrs old and sounds like I won't be repairing it[/quote]Some 15-years old amps are still great (Trace-Elliot and Ampeg as an example). Mark

[quote name='bumnote' post='1018777' date='Nov 10 2010, 03:52 PM'][size=4]So the amp is sensitive to 230 or 240V power supply (contrary to what was said above).[/size][/quote]I wrote that it is sensitive but I did not write that this is an issue, nor that this is a critical issue. In either case the amp will work correctly but the manufacturer provided a possibility to have a separate configuration for 230V and 240V. If this is available, why not use it? Apart from this, English is not my native language and you have to forgive me if I said something what is not precise enough. Mark

I think that this is ValveTone VT1 EQ Bass Drive from Dave Hall Amps. I would check the power supply (I don't remember whether it was 24V), and the valve. I would just replace it for a moment and see whether it changes anything. If this does not help, I would ask directly the manufacturer of the preamp. Mark

[quote name='bumnote' post='1018592' date='Nov 10 2010, 01:35 PM']If my Ashdown, Eden, and all my old Acoustic stuff was made prior to 98, designed and manufactured for 240 are running at 230 without problems, why is it an issue with Markbass?[/quote]Actually, I said exactly the oposite: [b]there is no issue with Markbass if the change is from 240V to 230V[/b]. Possible problems are only when the change is "up" and the change is substantial. For example, if you have an amp set to 120V (American version) and want to use it in Europe (230V). Then you will see this "magical smoke" mentioned in some Eden manuals (if the main fuse is not fast enough). Smaller voltage differences are handled correctly (even 268V as Dood mentioned). Mark

[quote name='bumnote' post='1018384' date='Nov 10 2010, 12:13 PM']Im just a layman but what happens to all the other electrical equipment in the UK that was manufactured prior to 2008 when the change was made. Presumably that was designed for 240v and is now running on 230. Is that at risk of damage, or is the markbass particulalry sensitive?[/quote] The change was from 240V to 230V. So it is less than 5% and the voltage was lowered. It means that the change is not critical at all. And I don't think that there is any risk of damage either with Markbass amps or any other equipment. Equipment from (resonable) manufacturers has to work correctly within the tolerance guaranteed by mains power supplier (you can check the tolerance on Wikipedia). And most probably slightly more. So I would say that the tolerance of +/-20% should be acceptable for most equipment. The problem is when a country changes mains power voltage up. If you e.g. imagine the US changing form 117V to 230V. Do you think that such operation would be possible? Most of the equipment would fail and this would be a disaster. Such a situation will never happen but there were many countries where the mains power voltage was changed from 220V to 230V. They could have some problems with e.g. light bulbs but this was nothing critical. What is interesting with Markbass F1 is that the change means slightly lower voltage for the power amp. And lower voltage means less power. Of course you will not hear the difference but I wonder what Markbass would recommend. And I'm not refering to places where you have still 268V. There, most probably the conversion hasn't been done and if some equipment fails, you can most probably ask the power supplier for a compensation :-). Mark

In Wikipedia UK is listed as 230V country: [url="http://en.wikipedia.org/wiki/Mains_power_around_the_world"]http://en.wikipedia.org/wiki/Mains_power_around_the_world[/url] - (formerly 240 V). That's why I wasn't sure. So possibly I don't have to edit my previous post. [quote name='icastle' post='1018269' date='Nov 10 2010, 02:42 AM']That's [b]exactly[/b] the point I was trying to make earlier. UK mains can be anything between 216V and 253V (230V +10%/-6%).[/quote]Yes, I know this may be a problem. But there is a delicate issue here: if your amp is set correctly and it fails due to incorrect mains voltage, you can get money from the power provider. But if the amp is set incorrectly and it fails, this is your problem (and additionally the guarantee is voided so in case of any other failure it will not be fixed for free). So setting the amp incorrectly may cause that you loose some money. [quote name='icastle' post='1018269' date='Nov 10 2010, 02:42 AM']If you follow the "out of warranty" rules you'd have to: 1) take a multimeter and measure the mains voltage at every venue 2) arrange for an authorised man in to change the jumpers before you plugged the amp in ...and the chances of any sane human being doing that are..? It is crazy to believe that a reputable and respected manufacturer like MarkBass, who have sold 1000s of these units, would ever contemplate issuing a piece of equipment that was going to fall apart because of a mere 5% fluctuation in mains voltage (5% being the difference between 230V and 240V).[/quote]I think that Markbass amps are not sensitive to 5% fluctuation of mains voltage. The requirement from Markbass is that the amp is set up as required in a given country and not in a given venue . And actually Lawrence should measure the voltage (e.g. at home) and decide which option should be selected. [quote name='icastle' post='1018269' date='Nov 10 2010, 02:42 AM']So, looking at this sensibly... if you were to select the 230V option and hit a 253V supply - you are 23V over the limit. if you select the 240V option and hit a 253V supply - you are 13V over the limit. I know which one sounds safest to me... [/quote]I agree. If you can get voltage between 210 and 250V it is safer to set the amp to 240V. But by doing this you void the guarantee. Are you sure that you may get 250V in UK? This could cause a failure of other equipment at home (light bulbs) and it is hard to imagine that some mains power provider is doing something like this. It's rather the other way round: they agree to deliver 230V but in reality they deliver 215V. Mark

[quote name='dood' post='1018142' date='Nov 10 2010, 12:21 AM']Although I have seen (and owned) amps that happily worked in the UK on a 230V setting (Ampeg SVP for example) the Uk's supply is 240 Volts (kinda average as it can fluctuate.) If it helps, to clarify, I can get a picture of a UK F1 inside for clearer pics of those lil jumpers.[/quote]Hmm, I'm sorry - my mistake. I thought that you have 230V (so the photo I posted is [b]for 230V only[/b]). Please disregard my previous post in this case. Please post a photo of this little jumper. F1 is class-D amp with a switching power supply (with maybe not the best stabilization) and 10V difference may case some problems with the power amp. Mark

Yes, fretFX [url="https://fretfx.com/"]https://fretfx.com/[/url] would be the best choice in this case. Mark

Lawrence, I'm affraid you got some incorrect guidelines how to convert F1 to 230V. That's why in the manual it is written that the amp should be modified only by qualified authorized Markbass technician. The fuse is listed in the manual and it is 4AT (and not 3.15A). Also the jumpers are slightly different than on the photo on the other forum. Markbass amps can be set to four different voltages: 100/120/230/240 and in each case it should be done differently. For 230V the "120-240V" jumper should be dissconnected (as on the photo). But there is another, little jumper for 230/240V selection (also visible on the photo). And on the photo it is set incorrectly. For 230V it should be in the middle position (it is marked J8). So the amp is sensitive to 230 or 240V power supply (contrary to what was said above). I'm new here and I don't know if I can post photos on this forum. Let's see. HTH, Mark [attachment=63537:MarkbassF1.jpg]