Transistor Tester Capacitor ESR Inductance Resistor Meter
Search the _Bay for
Transistor Tester Capacitor ESR Inductance Resistor Meter
usually under $20 USD you want the one with the square LSI not rectangular [on the bottom board]. Note the SOT23 pads lower left. Drop the FET on the pads, then hold down hard with tweezers, hit button and wait. Tester will hold the reading a while then shut down.
If you only have a few FETs your luck may not be good trying to get matched quads of each type. You would need quite a few, I am glad I started with 100 each type -- I already acquired 200 more.
Customs form is required for Canada...I can do it for YOU, but I still have a USA beta tester fellow to make happy first. I have most of what is needed.
Search the _Bay for
Transistor Tester Capacitor ESR Inductance Resistor Meter
usually under $20 USD you want the one with the square LSI not rectangular [on the bottom board]. Note the SOT23 pads lower left. Drop the FET on the pads, then hold down hard with tweezers, hit button and wait. Tester will hold the reading a while then shut down.
If you only have a few FETs your luck may not be good trying to get matched quads of each type. You would need quite a few, I am glad I started with 100 each type -- I already acquired 200 more.
Customs form is required for Canada...I can do it for YOU, but I still have a USA beta tester fellow to make happy first. I have most of what is needed.
OOOpz
No curve trace here. See my other posting about the tester. It does a Vgs and Idss for each device. Without this basic test people would be WAY WAY off grabbing 8 random FETs. DO I want to grade and match for the world? NO.
I AM trying to make sure folks understand how wildly different the readings are on a strip of FETs from the same reel -- this is DIY but ignoring the matching altogether would not be good. On one grid for example, 2.07 vs 3.47 Vgs miles apart. When faced with THAT, I'd want at least close basic readings, no? A DIY trying to order a small QTy on their own is going to be, I think, unlucky. EVen at the basic level.
No curve trace here. See my other posting about the tester. It does a Vgs and Idss for each device. Without this basic test people would be WAY WAY off grabbing 8 random FETs. DO I want to grade and match for the world? NO.
I AM trying to make sure folks understand how wildly different the readings are on a strip of FETs from the same reel -- this is DIY but ignoring the matching altogether would not be good. On one grid for example, 2.07 vs 3.47 Vgs miles apart. When faced with THAT, I'd want at least close basic readings, no? A DIY trying to order a small QTy on their own is going to be, I think, unlucky. EVen at the basic level.
Hi curryman, I'm pcpete from the minidsp forums....I've been following your progress here and on the minidsp forums..
I'm the guy who bought 3 ebay es9023 i2s dacs......I've got 2 of them working with the sharc by simply just splitting the clock signals...once I add the 3rd dac..the music stutters and then just dies....
Just wondering how you are making out connecting your 3 dacs to the minisharc....I'll probably switch to your design eventually...thx
so its single point and not at operating conditions, so not that much better that taking devices from right next to each other on the strip no, if the reading is taken for a different time, different temperature and in different operating conditions, its really not very useful.
you could test the very same device for a different amount of time, at a different current and voltage and different temperature and get a significantly different IDSS and VGS reading.
like many people who buy devices to match them in an endeavor that is supposed to make money, or simply for other hobbiests, it seems you didnt know what you were getting into. dont worry many before you have done the same, including myself, but for 200 boards, thats crazy
$20? you could build the same thing for $3-4 with a 9v battery, a resistor and a switch.
hey the listings say they test for mosfet VGth not VGS, but perhaps the standard VGS measurement is part of other options mot mentioned? gate threshold is more important for switching applications. you may be able to make a somewhat useful instrument out of it with a few mods though.
I would stick with Erno's method over this. i'll link in a minute, more work though, so maybe you dont want to know
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The cheap tester
The older model if the tester has a long rectangular LSI on the base board [some vendors have great pictures], the newer model has square LSI. Latest one I have seen also has V2.2 showing on the lower PCB artwork lower center front of base-PCB. So *if* you invest in one, get that or newer, or if you can afford better, great. It tests lots of components at a basic level, I am happy to have one.
The older model if the tester has a long rectangular LSI on the base board [some vendors have great pictures], the newer model has square LSI. Latest one I have seen also has V2.2 showing on the lower PCB artwork lower center front of base-PCB. So *if* you invest in one, get that or newer, or if you can afford better, great. It tests lots of components at a basic level, I am happy to have one.
handy yes, absolutely for a quick basic level test, but its accuracy will be generally worse than a fairly entry level multimeter (which most of us already have) that can do all the same things and much more, with a few added passive components.
but for reasonably accurate VGS testing for specific circuits, not so much.
this will produce better results
with the current sources adjusted to reflect your operating conditions. the noise of the current sources is not so important for the tester, so you could even use an LT3092 or IXYS adjustable current source
but for reasonably accurate VGS testing for specific circuits, not so much.
this will produce better results
with the current sources adjusted to reflect your operating conditions. the noise of the current sources is not so important for the tester, so you could even use an LT3092 or IXYS adjustable current source
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I did not have the time yet to do my own tests but after looking into the datasheets of the DSP the I2S data outputs probably have not enough drive capability to drive more than two or three receiver. Also reflections from not properly designed traces might be a problem (traces and connections on my board have 50Ohm impedance).
With my boards using its own MCLK we will not have any problem with MCLK and SDI (each data output is only connected to one board), but LRCLK and BCLK must be shared and thats a problem. I am just working on an active solution using buffers (either 74HC244 or CDCVLVC1104 Fanout Buffer) however that may take some time. I will also discuss this with DevTeam from miniDSP.
@qusp: You are of course perfectly right how to do proper matching. However I did several tests with different matching procedures and for the JG buffer we are talking about here the matching with those little tester will be perfectly OK. Output DC is close to zero and distortion is sufficiently low.
A better matching might reduce both further but if you really want to improve the whole thing you'd better think about changing the buffer design (e.g. preamp buffers). At the end you might end up with a better design but probably loose the appealing simplicity
Looks good I hope you like the sound! Looking forward to your report.
Yesterday I visited a friend and we listened to the DAC for a few hours. He was quite impressed and also liked the sound very much. After a few songs analysing the soundquality of the System we started to listen through his database and just enjoyed the music - always a good sign
BTW: DAC was powered by a 9V battery and the buffer was supplied with a salas shunt. Rest of the chain was macbook, miniSTREAMER, DAC, Bryston pre- + poweramp and Chario speakers...
I hope you like the sound! Looking forward to your report.Yesterday I visited a friend and we listened to the DAC for a few hours. He was quite impressed and also liked the sound very much. After a few songs analysing the soundquality of the System we started to listen through his database and just enjoyed the music - always a good sign
BTW: DAC was powered by a 9V battery and the buffer was supplied with a salas shunt. Rest of the chain was macbook, miniSTREAMER, DAC, Bryston pre- + poweramp and Chario speakers...
Just to followup - I have some troubleshooting in my future wired it up for testing and didn't get any output. Just started to check my v at various vias and pins and my granddaughter busted in. It was a mad scramble to clear my work area before those lightning quick 3 year old fingers hit their target.
I'll be back at hit when company clears. I'm sure I just did something stupid.
wired it up for testing and didn't get any output. Just started to check my v at various vias and pins and my granddaughter busted in. It was a mad scramble to clear my work area before those lightning quick 3 year old fingers hit their target.I'll be back at hit when company clears. I'm sure I just did something stupid.
If you have another DAC with I2S input you should make sure that the I2S signal are all good ... in other words that the known good DAC works with them. If not then that will have to wait.
Having looked at your photo just now I have a one thing that I would look at: the center pin [of 3] of the regulator next to C22 might not have any solder. You don't need R8, but having it should not cause you any grief. I had it soldered in place on my board for a while and everything worked great. The connections to the ES9023 using the 0 Ohm resistors are obviously a bit iffy, but difficult to check. What did you do to make sure that you are not making contact with the vias in the ES9023 footprint?
Best of luck.
Having looked at your photo just now I have a one thing that I would look at: the center pin [of 3] of the regulator next to C22 might not have any solder. You don't need R8, but having it should not cause you any grief. I had it soldered in place on my board for a while and everything worked great. The connections to the ES9023 using the 0 Ohm resistors are obviously a bit iffy, but difficult to check. What did you do to make sure that you are not making contact with the vias in the ES9023 footprint?
Best of luck.
grufti, good that you mention the vias under the ES9023! They are at GND potential and not covered by solder mask. I simply overlooked that for the first revision 
For the second board they will be covered
@MisterRogers: please also check the right solder joint of C6. Looks suspicious to me. While this will not stop the regulator working it will degrade performance. Hoping you will find the fault soon, I can very well follow your situation. My Kids are also amazingly fast
BTW: I ordered some V2 boards (hoping they will be delivered by the end of next week) and parts I will keep you informed about my progress...
For the second board they will be covered @MisterRogers: please also check the right solder joint of C6. Looks suspicious to me. While this will not stop the regulator working it will degrade performance. Hoping you will find the fault soon, I can very well follow your situation. My Kids are also amazingly fast
BTW: I ordered some V2 boards (hoping they will be delivered by the end of next week) and parts
I will keep you informed about my progress...Thanks for giving my board the 'eagle-eye' mates! Face-palm; forgot the isolation material above the vias under the E9023. Daniel reminded me, as did Pat; just zoned out and forgot. C6 & C22 are fine; I just need to remove and re-solder the DAC chip. At least that, but it's likely that. Thanks for the look gents.
I got a pair of
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Eye Jeweler Watch Repair 20x Magnifier Magnifying LED
they can be had shipped from the USA for very little. They are too powerful to do any work with but superb for inspection. Unless you have something better. A single-eye version is well under $5
http://www.ebay.com/itm/390573636947?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2648
Eye Jeweler Watch Repair 20x Magnifier Magnifying LED
they can be had shipped from the USA for very little. They are too powerful to do any work with but superb for inspection. Unless you have something better. A single-eye version is well under $5
Dampers
SO the ~47K damper R's go on the bottom? And the C201? doubles as a -V pin-header if you wish to insert -V to ES9023 "NEG" vs using it's charge-pump, eh? It looks very nice!
I did not measure potential impact, if any, on value of the Vreg resistor on ES9023 pin#6 to GND vs what -V you would read at ES9023 "NEG" pin, if using a CP cap [I do not know if there is a relationship at all]. In testing I took a reading of -V at NEG, then removed the CP cap and inserted the same value -V using a 79L05 and a 100R POT preset, then soldered in, then fine tuned to, in my case, -3.4V which is what my VOM read when CP had been running.
Thanks for the update, Pat
SO the ~47K damper R's go on the bottom? And the C201? doubles as a -V pin-header if you wish to insert -V to ES9023 "NEG" vs using it's charge-pump, eh? It looks very nice!
I did not measure potential impact, if any, on value of the Vreg resistor on ES9023 pin#6 to GND vs what -V you would read at ES9023 "NEG" pin, if using a CP cap [I do not know if there is a relationship at all]. In testing I took a reading of -V at NEG, then removed the CP cap and inserted the same value -V using a 79L05 and a 100R POT preset, then soldered in, then fine tuned to, in my case, -3.4V which is what my VOM read when CP had been running.
Thanks for the update, Pat
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