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**Jiminy** · 05-25-2011, 04:58 PM

Interesting. Would like to see where this ties in to the SD2100V2.
Have you made a circuitboard yet?

Will be interesting to see it go between 1.2Mhz and 4Mhz or so.
That will make it doable for the SD2000.

I don't think the SD2000 will quite get down to the 1Mhz frequency though. In another post, Woody states that the SD2000 won't go below 1.2Mhz. Maybe that's changed since his post in 2007.

Anyway, Great breakthrough. Anxious to see more of this in the future.
Thanks.

Jiminy

**mario** · 05-25-2011, 05:21 PM

The mod works. I have already posted a video.

The SD2100V2 will not function corretly over 2Mhz. However, I did say this mod should work with SD2000s.

I wrote the program to be flexible.

Default values are stored in eeprom. In other words, at address

0x00 = Default frequency
0x20 = Bottom Frequency limit
0x40 = Top frequency limit

variables are stored as unsigned longs. Simply open a hex editor and at address 0x40 change the value to what ever value you desire. Save a selected frequency and use address 0x00 as reference. If anything goes wrong, erase eeprom and default values are restored. To experiment, you may need a scope, but not necessary because the LCD will display your selected frequency.

I'm working on a AD9851+328P development board, but at 4x4 inches, it may be too big to incorporate inside the case?

**mario** · 06-13-2011, 11:03 PM

Ok gentlemen,

This mini board is out for production. I don't have a commercial interest, but found it cheaper to have 10 pcbs made instead of 3. In other words, I will have 7 extras once I get them. I will be getting them within 8 days of this posting.

Additions/Modifications:
- included voltage regulator to power board components. 7-10V in, regulated 5V out.
- Reworked filter. Now supports 1-50Mhz with a 7-10ppm distortion (as good as an oscillator crystal!)
-final board size is 3x4 inches

Although significant, the reworked filter is not really necessary since our application is limited to a 1-4Mhz frequency.

I reworked (or should I better say, borrowed) the filter to better fit ham radio applications. In other words, the original filter included in the schema is more than appropriate. Remember, the AD9851 is capable of exerting up to 180Mhz.

Having said that, I'm not sure what to do with the extra 5 pcbs. I'm thinking about selling a flashed Atmega328P+printed pcb+30Mhz Oscillator+encoder combo. Otherwise, I'm going to end up assembling them and selling them on ebay. I have found simpler designs selling for $80 (the AD9851 alone is USD $20!)

Last thing I would like to mention: I am more than willing to trade a working, assembled unit for a coil.

Coils I need, but won't limit myself to are: 17" DD and 10x12" DD coil. In addition to the coil being a working, shielded unit, I will require its resonating frequency, resistance and induction! These coils will be my main coils so I want them thoroughly tested.

If any one is interested send me a message.

Attached Files

lay.JPG (140.2 KB, 3750 views)

**Jiminy** · 06-14-2011, 11:17 AM

Mario, I'm interested in the flashed Atmega328P+printed pcb+30Mhz Oscillator+encoder combo. Pls PM me with the details to purchase.
/r
Jonn

**mario** · 06-14-2011, 10:23 PM

Thanks for the support Jonn.

I'll email you details after validating the boards. I received all components today and can't wait to start soldering them.

Regarding the software: on my next release, I'll release two hex files. I'll release one for the SD2100s and another for the SD2000s, with the only difference being the max/min frequency limits. My code should scale just fine for the frequency boost required by the SD2000s.

Like I mention earlier, my next release will be more about conserving power. I want to optimize my code. Right now, it's stable but very bloated. I will flash you the latest release, which I'll make available in the next few days.

**mario** · 06-14-2011, 10:59 PM

Also, I should mention that this mod should not be as refined on the SD2000s compared to the SD2100s.

On the SD2100s, the timings scale nicely in relation to the frequency. No additional modifications are needed for everything to work properly. The upper limit seems to be a ca. 2Mhz frequency. Past 2Mhz, the ground becomes too noisy with the stock timings.

On the other hand, I hear the SD2000s need to be adjusted for proper operation once you reach mid 3Mhz??(What does this mean? I don't know. I don't own one). In other words, I don't see the timings scale very effectively between the 1.5-4Mhz frequency range...and unfortunately, you can not flash your own timings like you can with the 2100s (If you already figured this out, good for you!).

**Jiminy** · 06-15-2011, 11:26 AM

Thanks Mario.
Yes, the SD2000 is crystal controlled and to change frequencies under normal circumstances you would have to change crystals or add a bank and selector switch, from what I've been reading and seen with other mods. It would seem that your mod would make it much cleaner and offer a wider choice of frequencies. As I have both an SD2100V2 and SD2000, I have interest in both. Getting the SD2100V2 updated first would be my number one priority. Additional coils for each? That's also in the queue to accomplish. Probably after I retire at end of next year when I'll have the time to set up my test equipment permanently in one place.

Keep up the fine work you're doing. . . .

/r
Jonn

**mario** · 06-21-2011, 01:15 AM

This sucks guys. I got the boards flipped!

Contacting pcb guys to see how this is going to work out...

**IBGold** · 06-21-2011, 04:14 AM

Hi Mario,
I can confirm that the SD2000 will run from sub 1.000 MHz to 5.000 MHz as I have one running on my 2000 with a VCO but has Jitter so slightly degrades the output from crystal version so your device could be the answer put me down for one of the 2000 devices when you get one up and running, to get the 2000 to run below 1.25 MHz is a simple removal of one resistor.

Regards, Ian.

**Jiminy** · 06-21-2011, 11:39 AM

Ian,
As I've already discussed with Mario, I am also interested in a board(s). I have the SD2100V2 and an SD2000. I still have issues with my SD2000 getting it running. I bought it off Ebay advertised as working. It arrived dead as a door nail. Looks like a previous owner did a hack job on it trying to mod it or something. Some of the paint was removed. I have been asking around looking for scope pictures of the different test points to see what stage/stages is/are working and what is not. Once working I want to mod it with some of Woody's updates for more sensitivity etc. When I say Mario's mod, it would be a perfect addition to having crystals hanging around the inside of the box.

So for the SD2000, what resistor do you remove and how/where would you connect it in???

I have been following Mario's posts with great interest with respect to the SD2100v2 etal. We haven't chatted before. Nice to meet you.!
/r
jonn

**gef12** · 06-22-2011, 04:35 AM

Hi Mario
yes interesting project .. would be interested if you are taking numbers...
good work

**IBGold** · 06-22-2011, 06:11 AM

Jiminy,

For the Modifications for the 2000 go to Ismael's site Minelabmods.com he has all the mods there well documented that you can download I will send you a PM with a picture of which resistor to remove I have mine switched and only switch it out when using frequencies below 1.25 MHz, I would think Mario's device would plug in on the center pin of the jumper-pins where you select which standard crystal you use and earth the same place as a multi crystal switch is connected and is explained in the 2000 mods this is the same as where my VCO is connected.

What are the symptoms of your 2000 what does it do or not do?

Regards, Ian.

**mario** · 06-22-2011, 06:39 AM

Ok guys,

I'm very disappointed with my pcb maker.

I'm left on my own since the boards are as "specified" by the gerber data. I shouldn't be surprised considering that their online record is spotty within the hobbyist community. Their support really really sucks. They have not responded to my last emails.

I had chose them because I had read (somewhat) good things about their work. However, If you need pcbs done, don't ever use MyroPCB.

Anyways, I reworked my layout today. It will be weeks before I get my new pcbs.

I think you'll appreciate the changes.

Also Jonn, you might want to post pics of your board. What modifications did the previous owner try to install? Which ICs did he change, etc..

**Jiminy** · 06-22-2011, 11:51 AM

Mario and All,

Sorry to hear about your plight with the PCB manufacturer. Hard to get good service these days. I often wonder how some of these companies stay in business with poor service. Keep me on the list for your board, whenever the situation gets resolved.

On my 2000, it looks like the only component that was changed was the IRF710. There was alot of the paint removed from the board also. (bet that was a real chore! hahaha)I talked with Woody awhile back, he recommended replacing the 2n7000 FET by the big CAPs, which I did. I did notice that the paint around the large CAPs was all yellowed so I ordered replacements for them. As I told Ian, the machine does nothing. The red LED just flickers once or twice when I turn it off. No sound whatsoever from the headset. I guess the next step is to go from the audio board test points towards the headset jack with a scope looking for any noise. I think putting any kind of speaker to the TPs would load down the circuit too much and not be fruitful. I would think that changing the tone and threshold should show some change at the TPs on the audio board. If so, that would be a plus. Maybe it's just a broken wire somewhere that is not showing itself to date.

v/r
jonn

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