Blatboy Posted April 4, 2012 Report Posted April 4, 2012 Greetings. I received my mb-6582 base pcb kit from smashtv a couple weeks back, and have finally gotten a chance to get started. Am hoping to get this done in time for a concert ive got booked in late may. This being said, I'm no expert yet at these builds, and I'm not gonna rush things too much as I'm hoping it'll actually work. This being said, I do have a quick question regarding the base pcb. 10K resistors R3_SID1 and R23_SID1 (actually for all four Sid modules) seem to have very little room between the holes for the leads. If I try to put them in, it's seems they will block the entrance for J2_SID1 or potentially short w another component. Or is a situation where I just twist it in a way that avoids all these things? Perhaps I'm doing something really stupid here so I thought I would chime in before I soldered them in... Thanks! Quote
nebula Posted April 4, 2012 Report Posted April 4, 2012 (edited) Some boards are designed so that the resistors stand up on one end. Usually this is to save space. Using Google I quickly found these two images as examples: Theoretically, resistors mounted in a "stand up" fashion like these may be slightly more prone to developing intermittent solder joints due to vibration, but in practice the difference is mainly cosmetic. LOTS of boards have resistors mounted in this way. If you don't want to mount your resistors like this, you can use smaller resistors, but you must observe the wattage rating. Miniature resistors are 1/4 watt resistors in a 1/8 watt package. I used them on my MB-6582. I'm attaching a shot of the miniature resistors like the ones I used in my MB-6582 (but the shot is from a different project). Click the image below to see what I'm talking about. Edited April 4, 2012 by nebula Quote
Blatboy Posted April 4, 2012 Author Report Posted April 4, 2012 Nebula, Thanks so much. You rock. I totally get it now. Interesting that on that one photo it seems they used heat shrink on the leads to lower the chances of short circuit in the really crowded situations. I'll stand those resistors up...though I am tempted to go to a local electronics store today just in case it's the type of thing they would have in stock. Are mini-resistors common enough to be in a Radio Shack (I live in NYC, so there are more options than just RS) or is it the type of thing that would only be available online? Quote
technobreath Posted April 4, 2012 Report Posted April 4, 2012 I'm not at all sure about it, but I don't think it's heat shrink tubes in the picture, but you could sure use those if u want to. It is fairly common to get those small sizes too. But if u want cheap, and good availability, you should try ebay. Haven't looked myself yet, but I'm sure there are a lot of chinese-ish ebay stores that can provide this for "free" hehe. However, if it's about the mb6582, I would imho say that I don't think you need them. It's not that crowded, and if u place the body of the resistor all the way down on the pcb, it will be steady enough to never make shorts. I have done this myself, and I have soldered a lot of pcbs hehe, and I don't worry about it (shorts) at all regarding my own mb6582. But if it make u feel better, of course :) Try it. You probably won't need to shrink them yourself at all, as they will shrink when u solder the leads in the first place :). And what do u mean by mini-resistors? You get em smaller than the ones in the kit, but not small enough to solder in a horizontal position anyway - unless u go surface mounted, but then again, the pcb isn't designed for those, and it will be a lot of work to solder them, especially if u don't have too much soldering experience from before :). But this got me wondering... I need to figure out what is common material to use in those situation, if it's heat shrink (I don't think it is) or some sort of woven nylon tubing or something. I've seen it in a lot of places myself, but I never bothered finding out what it is, and where to get it :P. Quote
Blatboy Posted April 4, 2012 Author Report Posted April 4, 2012 I certainly won't be doing heat shrink on this one... This is my first MB (not my first electronics project tho) and I'm not going to be adding too many variables to my game. I'll be happy with a solid working box. (That looks swell on the outside at least...) This being said, I do have access to a nice heat gun in my basement, so I may try colored heat shrink on my next batch of audio cables I make. One more resistor question: Regarding the "not required" 1.2K resistors R9_CORE2, 3 and 4: What would be a reason for putting them in? They weren't included with SmashTV's set, so I feel pretty safe in leaving them out. However, there wouldn't be places for them on the PCB without a reason, correct? I should be able to put some in after I install the IC sockets, but once those chips go in, I'm probably not going to want to dig in there again if there is a reason to put them in... Thoughts? Quote
nebula Posted April 6, 2012 Report Posted April 6, 2012 (edited) @technobreath: now that you mention it, I think you're right, the mini-resistors still needed to stand up in the MB-6582, but I was able to lay them flat in the x0xb0x. @blat: it's not heat shrink, those older boards have old-school resistors which are manufactured pre-bent with the exposed part of the lead dipped in the same resin that coats the resistor. I don't think you can buy them like that any more. It's totally not necessary in this application - there are lots of exposed conductive parts on a PCB anyway. It could only be a concern if there is a loose screw or something rattling around in the enclosure. The 1.2K resistor on the slave cores is not necessary in any standard build. I think you would install them if you were adding additional MIDI IN ports for the slave cores. Edited April 7, 2012 by nebula Quote
Blatboy Posted April 6, 2012 Author Report Posted April 6, 2012 I'll probably put in those extra resistors...I like the idea of maximum expandability. I don't think there's room in the back panel for more Midi ports the way it's set up now... but I like the idea of options. Thanks! Quote
nebula Posted April 7, 2012 Report Posted April 7, 2012 I don't recommend you install them until you're sure you need to. Quote
Gilesjuk Posted April 8, 2012 Report Posted April 8, 2012 The silkscreen on the board shows a ring around one of the holes, this means to have the resistor standing up. Quote
Janis1279 Posted April 9, 2012 Report Posted April 9, 2012 I don't recommend you install them until you're sure you need to. +1 I lost some time with those extra resistors in the slaves cores. My MB6582 board has 6N136 instead of 6N138 http://www.ucapps.de...136_variant.jpg Regards, Janis Quote
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