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Thread: Quantar V.24 replacement board

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    Default Quantar V.24 replacement board

    So, this project, as many of my projects have gone, met with a whole lot of delays. September is a pretty bad month for me to do any additional work, and this September was no exception, but hey, the convention went well and the hotel didn't burn down, thats a plus right?

    While making this I was learning Eagle, so I might not have done stuff really well. Its kinda a pain of a program, but nearly as much as Altium can be.

    The intent of this is to replicate the Quantar V.24 level converter board as closely as possible, in some cases I used exact replacements and in some cases I used other replacements. In choosing the RS-232 chip I spent some time looking at Maxims various offerings, I was looking for one that had commodity replacements (like how the MAX232 comes from TI and Analog as well), but ended up choosing the MAX241 because it specified true RS-232 levels and indicated compatibility with V.24 in the specifications. Other components were chosen based on my own preferences and methods, in many cases you can substitute equivalent replacements.

    Currently the design is not quite ready for fabbing boards, I would like any input and checking that the p25.ca community can provide before I send the boards off. Once I have the gerbers ready I will post them and the Eagle files so that you guys can make your own. This project is intended to be Open Hardware.

    Explanation of files:
    Daughter Board.pdf - This is a scan of the schematic page for the Motorola V.24 board, including part numbers.
    Quantar Level Converter BOM.pdf - This is the bill of materials for the replacement board.
    levelconverter.pdf - This is the schematic for the replacement board.
    Attached Files Attached Files


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    Excellent project start!

    Having played with the OEM V.24 boards, I have a few suggestions of features that would improve upon the original design in terms of diagnostics and installation.

    1) I would include jumpers or dip switches to be able to latch the CTS and CD inputs high. I found it annoying having to accomodate external jumpering of the RJ45 cable to fool the handshake lines. There's really no point to the CTS and CD, but it needs those to be high in order for the Quantar/Astrotac to send the digital idle link check pulse on the TXD line.

    2) How difficult would it be to add some LEDS on the clock and data lines? The LEDs don't need to be external, but if they were close to the front edge so you could peek in and see what was going on, I think it would help immensely. This way you can tell at a glance if it was sending and receiving both clock and data signals.

    Thanks for taking the time to get this rolling.

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    A good start!

    U7 and U8 are not needed for use in a Quantar, in fact all the components to do with port 2 can be left off, unless you are using the board in a comparator. Also remember that most people wanting a board will not have the SCM front panel with the necessary cut outs for the RJ45. The solution is to mount the connector at right angles, it is easy enough to route the cable out the back. Don't forget to allow for stand-offs to hold the board.
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    If you could make two different footprints for the RJ45 on the board, one at a right angle as Astro suggested and one in the normal orientation, that would allow someone to proceed with whatever works best for them. I would also keep the traces for the 2nd port, just let the builder omit the components if they don't need the 2nd port. Guys like me have been stealing the boards from Astrotacs to put into stations, so it would be nice to have a drop-in Astrotac replacement V.24 board as well. Would be great to silk screen on which components are for port 1 and port 2 so it's easy to tell if you're putting the right stuff on at a glance.


    Concerning the front panel, I just took a sheet metal hand nibbler and cutout the necessary rectangle on my Quantars for the ports to feedthrough- only takes about 20 minutes to do. Just need to drill a starter hole in the middle and then nibble away. Here's a pic of one I nibbled.
    IMG_20131009_204142.jpg
    Last edited by mizzotch; Nov 12, 2013 at 09:13 PM.

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    Has there been any more progress on the V.24 board? My Astrotac is hungry

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    Its up on OSHPark:
    http://oshpark.com/shared_projects/5kZPCBGY

    Im attaching the BoM as an XLS because thats better for managing what needs to be ordered.
    Attached Files Attached Files

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    Well done!
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    I recommend verifying the schematic on your own before using this.

    Also, theres a possibility that the boards might have defects that make it past verification. So I know theres a 3 board minimum, but you really should plan on making 3 (still much cheaper than the actual board).

    Other notes (since I'm not really f***ing tired now, as opposed to last night):
    * I know theres no RJ45 connector, in my application I am routing a cable into the unit from the back and connecting to that, if you need an RJ45 on front, I think the solution would be to add a header connector to a short length of cat-5 with a keystone jack on the other end. The limitations that prevented me from making this physically compatable with the other board are: 1. Cost, the other board would have cost about $50 each to make. 2. I don't have an Eagle license that supports that large PCBs, so it would have had to be done in some other software or after I pay the large fee to upgrade to a better Eagle license.
    * The board has no standoffs. Partly to save space and partly because its so small.
    * Yes, it really is barely bigger than the 50 pin header.
    * Speaking about the 50 pin header, pin 1 is near the label for the header, I need to make better artwork that is more clear on where that is. Same (IIRC) with the 8 pin header.
    * This board may be hard to solder because some of the vias are really close to pads. The separation was set to 10mil, which seems to have been not enough separation. Better luck in R2.
    * It only comes in Purple.
    * This is pretty much the first board I started in Eagle. Before that I was using Altium. I hate all EDA software now.
    * Oddly enough, this is not the first board I finished in Eagle, and its a good thing it wasn't.
    * R2 will be open hardware.

    Disclaimer:
    Verify before using, some assembly required, not valid where prohibited, has not been simulated, has not been tested, do not taunt happy fun Quantar, read instructions before using.

    Edit:

    Feedback welcome!

    Also: This is intended to be a one-to-one replacement, I may at a later date incorporate features as requested previously or in the future in this thread. Right now I have bigger fish to fry.

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    Awesome contribution! That's pretty cheap to make...should be about $30/each for QTY of 3 including parts. Biggest thing I don't see on the parts list is the 50 pin header connector P/N. I think I Astro Spectra said he might have the part # for that...?

    I'd like to give this board a try soon. I think you're right about the difficulty to solder....some of the vias are really close.

    This mini board approach I think will work out nicely for keeping cost down. Use 1 board for Quantars and 2 for Astrotacs.

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    We need to send Foxconn a contract to mass-produce these boards Wishful thinking? I doubt the workers would start committing suicide over this board. They only seem to do that for Apple stuff.

    Kayfox, excellent work sir.

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    The 50 pin header is just a 5 pin length of dual row header (0.1in/100mil spacing), [strike: although Im worried that it wont fit with that part]. I didn't put down a part number because I get it in bags of 100x 80 pin dual row headers and cut it down to size. Same with the 8 pin header, except that one I was looking for a part for but DigiKey doesn't make it easy to find parts by "I know what this should look like" anymore.

    The DIP switch is also missing from the BOM, should be able to use most 2 position dip switches.

    At any rate, this is the first revision, I intend to have another revision in/by Feb that works better.

    Edit: looked at some photos of the TTN4010 and it looks like it uses the standard header, so nevermind about it possibly not fitting. I still recommend making site its not touching the outside of the SCM compartment when installing.
    Last edited by kayfox; Jan 02, 2014 at 04:51 PM.

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    The box header I have used is AMP TE Connectivity P/N 5-534978-8, it is available from DigiKey see:

    http://www.digikey.com/product-detai...973-ND/1165225

    K1 is rather close so it's not a given the AMP header will fit this board.
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    Quote Originally Posted by Astro Spectra View Post
    The box header I have used is AMP TE Connectivity P/N 5-534978-8, it is available from DigiKey
    Did you check to see if the sides of that clear? Normal box headers dont work on the wide connector Motorola likes using.

    Also, I guess I'm re-doing the whole thing. Yet another* 3ware related data loss occurred today and it took some of my eagle work with it, including this.

    But... It shouldn't be that bad of an impact considering I should be able to get it done faster this time because I wont be learning Eagle as much at the same time.

    * This brings 3ware related data losses to over 4.5TB and 3 arrays. This one occurred because of a UI issue: it didn't clear some checkboxes (After refreshing the page and giving me an error message) when I was trying to get a drive moved around to rebuild an array, so I ended up deleting the array and the JBOD the timed out drive ended up as, yeah, no confirmations either. Impacts were minimal, I lost a bunch of files I haven't used in years and my projects folder, which wasn't really being used for all my Eagle projects, just this one.

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    Yes, I've done my own boards with them. There is a PDF available with all the dims at the link I posted.

    If you are going to redo the board then I can suggest some cost saving mods, for example the relay can be ditched for a Clare Opto-MOS solid state relay.
    Last edited by Astro Spectra; Jan 06, 2014 at 11:27 AM.
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    Hi,

    first I have to say thank you very much for the great contribution. I have build this card, but I have run into some trouble, so I will share my experience. I suggest to check the PCBs I ordered 6 Board from OSH Park build one, before I put it onto my Wireline card I would check it on my work bench, after applying 5V to the card it draws about 600 mA so something was obviously wrong with the board. I figured out that the MAX241 had no ground connection. By looking at the back of the PCB I saw that the ground had some interruptions, I solved this with some bodge wires. Another issue was Pin 25 SHDN the shutdown Pin from the MAX241, after fixing the ground problem I was wondering about that the Max draw only about 10 micro Amperes and when I applied some Signal from my function gen nothing happened, after I studied the Datasheet of the MAX I thought that the SHDN Pin must not be on the +5V rail to get the MAX working it must be grounded. It can easily be done by lifting Pin 25 of the board and put a solder blob across Pin 24 and 25. After I did so I was able to do the first tests with two Quantars linked together and it worked well. The only thing I'm a bit wondering about is the relay does nothing, but it can be an issue with the WL card Pin 33 does not go high it provides only a square Wave equal to the output on Pin 43. I will investigate that and check this with some other WL cards floating around. So this maybe helps some others who are going to build this V.24 replacements.

    Alex
    DC5AJ

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    Good post Alex, here is my install on a W/L board:

    v.24.jpg

    Note I used the AMP Connectivity connector I mentioned in post #12. I also used a cable tie to hold the cable to the board and used a back-to-back RJ45 to RJ45 snap mount block that clicks into an existing cut-out in the rear panel of the Quantar. That's the black block on the end of the RJ45 flat cable. It was neater than cutting a hole in the front of the SCM panel.

    The relay is not required if you are happy to choose just one clock configuration. Since I see you are following the Cisco thread then you want to have both the receiver and transmitter of the Quantar work with external clocks. I just jumpered the relay pads and left out the relay and catch diode.
    Last edited by Astro Spectra; Apr 04, 2014 at 09:28 PM.
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    Hi, you are absolutely right with the relay, I did it the same way and jumpered the pads for external clocks. The RJ45 snap mount block looks really good, I would appreciate it if you can me a part number of it, for testing I have only a cable running out of the front without front panel installed, for final installation this snap mount block will be a very good solution.

    Alex
    DC5AJ

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    Kayfox,

    Did you get chance to work on Rev. 2 of this board?

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    Yeah, I'm working on it. It took a while to get everything fixed with the fileshare it was on (RAID issue, etc, but because I'm a motherf***ing wizard, its fixed) and now I'm trying to get to the bottom of why Eagle is leaving orphan grounds.

    I think I'm going to keep using Altium for my non-open hardware projects.

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    All hail the wizard!

    I'm a total n00b with PCB layout, but a friend of mine had success for a small project with this software: http://www.4pcb.com/free-pcb-layout-software/

    I don't think it's open source (you have to buy your boards from them), but it's free and apparently works well enough. Disclaimer: I have no experience with that software.

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    Can I open the gerbers with the free version of Eagle or is there a different file format you can share it in so I can hack on it? I am only familiar with the free pcb software that mizzotch mentioned but want to learn Eagle and figured this would be a fun way.

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    Quote Originally Posted by JeepFrog View Post
    Can I open the gerbers with the free version of Eagle or is there a different file format you can share it in so I can hack on it? I am only familiar with the free pcb software that mizzotch mentioned but want to learn Eagle and figured this would be a fun way.
    Eagle is not working properly for this project,* so I'm considering re-doing it in Altium, which is the software I usually use.

    You cant import gerbers into Eagle, the gerbers are just files that tell the machines at the PCB fab how to make the PCB.

    The finished product will be released on Github at some point when I have solved the immediate issues with the design.

    * It is creating independent isolated ground islands from a ground polygon, this is, from what the documentation says, improper behavior.

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    I too greatly appreciate your efforts. Is there anything I/we could do to support your work? You mentioned an upgrade license - i would be willing to pitch in.

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    Updated board with less issues:

    https://oshpark.com/shared_projects/hYhEEF6o

    Changelog:
    * Moved some stuff around in a (futile) attempt to get the Eagle autorouter not to crap out as much.
    * Fixed floating grounds (see above).
    * Fixed Shutdown pin connection.

    I tested the R1 version of this board with the above modifications a couple of weeks ago at a convention setup and it worked great.

  25. The Following 5 Users Say Thank You to kayfox For This Useful Post:

    DC5AJ (Jul 21, 2014),khw (Jul 22, 2014),mizzotch (Jul 22, 2014),wd9cms (Jul 21, 2014)

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    Thanks for all your work on this, it's awesome. I went ahead and order a set of boards to give it a try. I want to link my UHF Quantar to my 900...

    Bill
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