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vladosh
Joined: Aug 02, 2010 Posts: 659 Location: macedonia
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Posted: Wed Dec 07, 2022 8:54 am Post subject:
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i never really cared about math , i like to explore as to what tip and tricks are there about a circuit ,and usually that's enough ..i only wish i could buy my parts from farnell or mouser or banzai or so ..i like to think they are more careful with fakes _________________ http://synthacks.blogspot.com/ шематикс |
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Wed Dec 07, 2022 11:12 am Post subject:
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useless? it tells type, pinout and readings of any Si or Ge transistor or FET, plus resistance and capacitance both static and dynamic (photocell for instance), plus inductance, etc, etc. I'd say it's far from useless.
For FETs being out of reach for the ATMEGA tester you have that ultrasimple diagram from first link (you can use ATMEGA tester first to find out the pinout and consult datasheet) _________________ Fer
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vladosh
Joined: Aug 02, 2010 Posts: 659 Location: macedonia
Audio files: 46
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Posted: Wed Dec 07, 2022 11:54 am Post subject:
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i dunno ,the one i got labels the P channel fet as PNP or NPN ,and the J112 like resistor so i don't really find it useful ,maybe that's useful for someone who understands more but it does not give me the pinout GDS ,can you show me what kind of tester you got ,or if you can suggest any ,it seems this that i got can read Mosfet but aparently not JFET
i got this one https://youtu.be/KS-JWDh0IbA _________________ http://synthacks.blogspot.com/ шематикс |
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Wed Dec 07, 2022 12:41 pm Post subject:
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Why don't you open a thread for this? It will be interesting/helpful for many of us _________________ Fer
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vladosh
Joined: Aug 02, 2010 Posts: 659 Location: macedonia
Audio files: 46
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Posted: Wed Dec 07, 2022 12:43 pm Post subject:
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i just realized i have some PN4391 so i try it ,and it gives me just resistance of 20 or so ohms ,nevermind ..whole thing i thought the testers worked with jfets but i also see someone testing mosfets on yt also recognized as npn ,guess i'll just give it a shot about the 158 i planned to make 2 of those but if that doesn't work ..and it'll prolly be 2023 by then ,who knows what .. _________________ http://synthacks.blogspot.com/ шематикс |
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vladosh
Joined: Aug 02, 2010 Posts: 659 Location: macedonia
Audio files: 46
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Posted: Wed Dec 07, 2022 12:48 pm Post subject:
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if anyone has more luck with JFETS ,here's my layout ,should be correct ,all npn pnp pairs used in the oscillator are matched BCM847/857
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_________________ http://synthacks.blogspot.com/ шематикс |
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Wed Dec 07, 2022 1:30 pm Post subject:
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vladosh wrote: | i just realized i have some PN4391 so i try it ,and it gives me just resistance of 20 or so ohms ,nevermind ..whole thing i thought the testers worked with jfets but i also see someone testing mosfets on yt also recognized as npn ,guess i'll just give it a shot about the 158 i planned to make 2 of those but if that doesn't work ..and it'll prolly be 2023 by then ,who knows what .. |
Are you identifying/using correctly the tester's 1, 2, 3 holes in the adapter?
For instance, mine uses the one in the center-right for 2, like 11112333
New ones I think use 12223333
*** You need to use 1,2,3 for the tester to read any 3 leg device. I mean you are maybe using 2,2,3 or so and the tester can't read them.
Also for resistors and capacitors, if you want a dynamic reading, you must use 1 and 3, not 1-2 or 2-3 _________________ Fer
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vladosh
Joined: Aug 02, 2010 Posts: 659 Location: macedonia
Audio files: 46
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Posted: Wed Dec 07, 2022 1:42 pm Post subject:
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i use the ones labeled as 123 ,nevermind really ,this is no big deal , i've built many 258's without this ,so it's all up to how correct is schematic , other thing i found at muffs is by la67 a comment ..the 1.5K resistors tied to the fet can be up to 2.5K if the transistor itself is off in idss ,someone has tried this and it works fine and it makes sense looking at the schematic ,i also found the same shaper in electronotes vco ,i am still waiting for the pcb's ..if it works great ,if not ..will have to find some other vco to replace it ,maybe pure sine vco from electronotes coupled with buchla timbre that also has a Jfet haha _________________ http://synthacks.blogspot.com/ шематикс |
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Wed Dec 07, 2022 1:48 pm Post subject:
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read ebolatone's blog (link up the thread), he used trimmers initially on that position _________________ Fer
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Wed Dec 07, 2022 2:56 pm Post subject:
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vladosh wrote: | i just realized i have some PN4391 so i try it ,and it gives me just resistance of 20 or so ohms ,nevermind ..whole thing i thought the testers worked with jfets but i also see someone testing mosfets on yt also recognized as npn ,guess i'll just give it a shot about the 158 i planned to make 2 of those but if that doesn't work ..and it'll prolly be 2023 by then ,who knows what .. |
as I said, 4391 will confuse automatic testers for shure _________________ Fer
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Wed Dec 07, 2022 5:31 pm Post subject:
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Just uploaded version 1.5 of my redrawn 158A schematic (just a few small graphic changes for more clarity)
BTW, it looks like a running dog! _________________ Fer
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Thu Dec 08, 2022 6:07 am Post subject:
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Re. "grey" unknown function wire:
Maybe it can be used as external freq. input while having "F" hardwired as "internal" for the freq. pot?
It looks like it
Anyone tried this or have new info about "grey"? _________________ Fer
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