HH D R18 and R23 - calibration question

[Carl-NC]

If you've already removed the parts, then try to get it calibrated as written in the document. I'm not 100% sure the alternate method will work.

[ManBearPig]

Hi Carl, I've only got IC5, IC8, IC11, IC12 and IC9 removed (i have them socketed) and i did have a jumper from pad 1 of IC8 to ground (was using IC9 pad 4, as i have it removed), but all the rest of the soldered parts are still in place. Wife just went out so i'm going to take over the kitchen again for a coupe hrs. If that procedure is with all ICs in I can just pop them back in, thank god i did sockets lol Will try doc procedure first with them out again, if no joy i'll try the alternative method. Thanks Carl, I appreciate the help, will update with results again soon

[ManBearPig]

Just finished checking all the external pots, wanted to be sure there wasn't a broken wire at the join on any pots and that they were all operating properly before i went further first but they're all ok. Tried to trim (with black lead to IC6 pin3 this time) as per doc. Voltage still hanging around at +4.31. Will try the alternative method next and post results fingers crossed (and toes, eyes, etc)

[ManBearPig]

Hey guys, sorry havent checked in with any news on the build, been away but back now and gonna hit it again tonight (at work now). Will post how it goes when ive got some results

[ManBearPig]

Hi Guys, didn't get much done last night on it, but my scope arrives on thurs/fri (well, it should, express post here in Australia isn't quite what it implies) so i'm thinking it's probably worth waiting and doing it with that, before i go cutting jumpers etc, although i did pick up new digital station type iron this week so if i have to... It's been a very long time since i've used an oscilloscope, so i may have to re-aquaint myself with some procedures lol, so if anyone has any pointers on doing the calibration of R18 and R23 with a scope, in anticipation of it's imminent arrival (the second it gets here i'm going to be wanting to get stuck in I can't wait!) that would be awesome. It may have been discussed else where in the forum here, so i apologise if I've missed it, if so though can some one please point me to it? I do have the scope pics at the end of the HH article to refer to, i fact im going to go over them again now.

As always, thanks everyone!

Tom

[ManBearPig]

Hi guys, just an update, I haven't given up. I'm STILL waiting on my "express post" scope to arrive (found out after last post that he didn't mail it till five days after i payed! Free express postage my... ankle. Me thinks his 100% ebay rating's about to take a dent ) Was cheap deal though, guess you get what you pay for, sometimes...

Am just playing with Arduino and reading up on using a scope till it rocks up, hoping Monday (Not holding my breath though)

Will be back as soon as this damn thing arrives!

A side note: Silverdogs' kit got here in about five days, from the UK, on the other side of the world (from me anyway, thanks Silverdog). This scopes supposedly coming from Sydney, and i'm in Perth on the other side of the country and has been two weeks. Australia must be way way bigger than i thought it was

[javifalac]

Anyone could show me the summary of all the steps? Each Tp, and control the oscilloscope.
Please.
thanks

[ManBearPig]

Hi Guys,

Scope arrived, but it's not what i thought. Can't go over 50v so isn't likely to be much help i suspect, going to have to save for a proper one, there's no getting around it. So, with my new soldering iron, after alot more desoldering practice and a bit more confidence, i'm going to remove whats necesary and go from there with multimeter. Sorry haven't checked in for awhile, wife just had a baby so things been super crazy.
I think i will try the alternate method described earlier in the post by Carl, and if still no joy i'll work back through the steps and reove parts back to the calibration step. Once i get some progress to report on, i'll post back with an update

Cheers guys

[mickstv]

Hi Guys,

Scope arrived, but it's not what i thought. Can't go over 50v so isn't likely to be much help i suspect, going to have to save for a proper one, there's no getting around it.
Cheers guys

Check the leads that came with the CRO, they should have a switch on the side to select 10:1 ratio. If not get on Ebay and look up CRO leads that have 10:1 and 1:1 ratio switch. It might also be listed as 1x 10x 100x

[Carl-NC]

Many scopes are limited to 50V, as Mick says get a 10x probe, cheap probes from China are as low as $15 or so. For PI I also recommend a 100x probe for looking at flybacks.

[ManBearPig]

Ahh, ok cool that sounds like a good way around it! Haven't had time to desolder yet so i'll hold off and try this. Yeah was only a cheapy, the one i wanted was a bit out of reach at the moment unfortunately (always the way). It does have a 10x switch on the side of the probes, i assume theres a resistor in there? maybe i could jump to a bread board with the correct value resistor in series in the mean time? I'm just wondering, i'm not about to just do that in case i cook something! I'll have a look for some proper 100x probes now on ebay anyway, right tool for the right job and all. Thanks guys, that's awesome to know, I suddenly feel like i haven't wasted my money!!
Cheers guys!

[ManBearPig]

Just quick question, if i add in series 90M resitance (i'm thinking a multiturn trimpot for accuracy) with the probe set on 10x, to total 100M would that do the job in the meantime? Sorry if this seems a silly question, I'm just anticipating a long delivery time if i can't get it locally and would love to get this baby going (it's pretty much finished with two different mono coils built, just dying to hear it pick up my wedding ring for the first time!)
Cheers guys

Edit: I think i might just buy one, can get locally, it looks like less trouble after a bit of reading!

[mickstv]

Ebay is cheaper, but if you have a Jaycar store close by check the links below.

http://www.jaycar.com.au/productView.asp?ID=QC1902

http://www.jaycar.com.au/productView.asp?ID=QC1903


Or better still check out Altronics, the prices are better.

http://www.altronics.com.au/p/q0174-...be-cro-x1:x10/

http://www.altronics.com.au/p/q0176-...be-cro-x1:x10/

[ManBearPig]

Hi mickstv,

Yeah the 100x one at jaycar is the one i'm looking at, is pretty close by. definitely cheaper on ebay tho! But i hate waiting for postage so I'll probably get that one come payday. Yeah altronics is quite often cheaper ay, plus they also sell kapton tape (jaycar doesn't have that) which is handy. I like going there when I'm nearby, switches are much cheaper there too.

[mickstv]

Hi mickstv,

Yeah the 100x one at jaycar is the one i'm looking at, is pretty close by. definitely cheaper on ebay tho! But i hate waiting for postage so I'll probably get that one come payday. Yeah altronics is quite often cheaper ay, plus they also sell kapton tape (jaycar doesn't have that) which is handy. I like going there when I'm nearby, switches are much cheaper there too.

Just make sure before you buy that 100x Jaycar one also has a switch to select 1x (1:1 ratio). I think the 10x one from Jaycar will be the better choice.

All my leads are the 1X 10x and that's fine for looking at the flyback pulse of any typical PI circuit.