jamesmking Posted June 4, 2021 Report Posted June 4, 2021 (edited) 12 hours ago, johnwmclean said: Teehee... I was kind of thinking this was completely out of character for James. Meanwhile I bought some C2M1000170Ds from eBay and kind of resigned them to be fakes... They’re looking a bit beat up from being jumbled around, but I think the gamble paid off. time to get out the dca75 and dy294. Your photos look consistent with my known good from mouser. If they are fakes they are extremely good. Edited June 4, 2021 by jamesmking 1
johnwmclean Posted June 4, 2021 Report Posted June 4, 2021 breakdown voltage is ~1510v (data sheet spec is 1700v min) but limited by the dy294 1500v between c and e I'm fairly confident they are genuine funnily enough the eBay source I bought from is the same listing starcat referenced with the fake images
jamesmking Posted June 5, 2021 Report Posted June 5, 2021 (edited) 8 hours ago, johnwmclean said: breakdown voltage is ~1510v (data sheet spec is 1700v min) but limited by the dy294 1500v between c and e I'm fairly confident they are genuine funnily enough the eBay source I bought from is the same listing starcat referenced with the fake images Maybe the seller was just lazy and use a photo from elsewhere? yep my dy294 says around 1520V breakdown into an open circuit, so that's good evidence your transistors have a breakdown exceeding that. Also given the markings look correct I would say you have a winner and the price is not crazy low either. (I don't understand why the 294 displays a 1 in the left most column on the 200V range into an open circuit but does not do this on the 1500V range...). its possible the seller sells a mixture of fakes and non fakes. For example I purchased some 2sk216 and 2sj79 from littlediode on ebay and the sk216s where genuine and the 2sj79s where obviously fake, wrong markings, leads wrong, crazy low breakdown voltage. Returned them. Seller is still selling the same fakes years later. nikko on ebay also sells fakes. For example their 2SA1968 are fakes. they are not even NPN transistors.... Edited June 5, 2021 by jamesmking 1
kevin gilmore Posted June 5, 2021 Report Posted June 5, 2021 littlefuse dalbani littlediode nikko... all the same company. and yes they sell lots of fakes. 2sa1968 are pnp. but if they test as 30v transistors, they are definitely fakes. 1
jamesmking Posted June 5, 2021 Report Posted June 5, 2021 (edited) On 6/5/2021 at 1:10 PM, kevin gilmore said: littlefuse dalbani littlediode nikko... all the same company. and yes they sell lots of fakes. 2sa1968 are pnp. but if they test as 30v transistors, they are definitely fakes. Hi Kevin, I did not realise they where all the same company. 😞 The spec sheet I have (dated 1995 September) says the 2sa1968 are NPN: However we already have a specsheet which can't even get the pinout right for the G3R450MT17D so who knows anymore... Every single 2sa1968 they sold me (54 of them) all tested on the peak dca75 as PNP rather than NPN and broke down at around 200V instead of 900V utter junk. Edited June 7, 2021 by jamesmking
Kerry Posted June 5, 2021 Report Posted June 5, 2021 That looks like a bad spec sheet. 2SAxxx transistors are always PNP and 2SCxxx are NPN 1
jamesmking Posted June 5, 2021 Report Posted June 5, 2021 (edited) 4 hours ago, Kerry said: That looks like a bad spec sheet. 2SAxxx transistors are always PNP and 2SCxxx are NPN Seriously! OMG how many more bad spec sheets can we find in a week.... ok here's another spec sheet for the 2sa1968 (dated September 1998).. also says NPN... Sanyo datasheet (September 1998) also says NPN for the 2sa1967.... Hitachi datasheet (unknown month 1991) for the 2sa1960 says NPN.... looks like many of the 2sa196X sheets are wrong then... Edited June 5, 2021 by jamesmking
starcat Posted June 5, 2021 Report Posted June 5, 2021 The spec sheet that's on the google drive says for the 2sa1968 npn as well. 1
Blaino Posted June 7, 2021 Report Posted June 7, 2021 G2R1000MT17D GeneSiC Semiconductor | Discrete Semiconductor Products | DigiKey Will this serve as a sub for the C2M1000170D? Looks very similarly rated except for power dissipation of 44W instead of 69W. 1
Sebtdi Posted June 28, 2021 Report Posted June 28, 2021 Hello Folks Finished the power supply section this weekend. Question from a newbie perspective: looking for instructions how to adjust/test for the High Bias voltage before installing the new Carbon boards.. R21-50K ? This is for a Golden Reference LH+LV Version 2.0 Readings: Bias H to ground = 436 V U7 Current regulator pad IXCY10M90S (right of R21) to ground = 650 V B+ = 418.5 V B- = -417.6 V Thank you
starcat Posted June 28, 2021 Report Posted June 28, 2021 (edited) On 6/7/2021 at 7:20 AM, Blaino said: G2R1000MT17D GeneSiC Semiconductor | Discrete Semiconductor Products | DigiKey Will this serve as a sub for the C2M1000170D? Looks very similarly rated except for power dissipation of 44W instead of 69W. Looks good. Have you tested it already? The G3R450MT17D is a replace as well. It was mentioned somewhere above. Edited June 28, 2021 by starcat
johnwmclean Posted June 28, 2021 Report Posted June 28, 2021 C3M0350120D could be a good alternative. 1
Sebtdi Posted June 29, 2021 Report Posted June 29, 2021 8 hours ago, Sebtdi said: Hello Folks Finished the power supply section this weekend. Question from a newbie perspective: looking for instructions how to adjust/test for the High Bias voltage before installing the new Carbon boards.. R21-50K ? This is for a Golden Reference LH+LV Version 2.0 Readings: Bias H to ground = 436 V U7 Current regulator pad IXCY10M90S (right of R21) to ground = 650 V B+ = 418.5 V B- = -417.6 V Thank you I was able to replace a Zener diode to 100V instead of 130V - now have 580V bias supply Thanks to Kerry for his assistance!
mwl168 Posted June 29, 2021 Report Posted June 29, 2021 That’s great. Good luck with testing the Carbon next.
Sebtdi Posted June 29, 2021 Report Posted June 29, 2021 14 hours ago, mwl168 said: That’s great. Good luck with testing the Carbon next. Do you know the correct procedure to adjust the offset and balance for each channel? The Carbon boards have 4 adjustment pots per channel https://drive.google.com/file/d/1f72uj9bDsLgNH3xHh9e1PJFjQzICSAX0/view?usp=sharing
starcat Posted June 29, 2021 Report Posted June 29, 2021 (edited) On 6/29/2021 at 3:55 AM, Sebtdi said: I was able to replace a Zener diode to 100V instead of 130V - now have 580V bias supply Thanks to Kerry for his assistance! Very nice, congrats! Are you building the amp and PSU in separate chassis? Need moar pics 🙂 Edited July 11, 2021 by starcat
waltzingbear Posted July 4, 2021 Report Posted July 4, 2021 that is Kerry's mini PSU board that contains all GRHV & GRLV supplies, so that is a one chassis Carbon.
johnwmclean Posted July 11, 2021 Report Posted July 11, 2021 Since KSC5026M is 0 stock worldwide, could I drop in the original part 2SC3840 without issue into the latest HV designs?
bbest Posted September 21, 2021 Report Posted September 21, 2021 Next generation of replacement C2M1000170D is https://www.wolfspeed.com/1700v-silicon-carbide-mosfets?gclid=CjwKCAjwhaaKBhBcEiwA8acsHIXAWPUxDjNOkcr759hHaI2oBqpaPVCLSMR1UxDcq8RTelBzV8daMhoC110QAvD_BwE Power Dissipation 520W
johnwmclean Posted September 21, 2021 Report Posted September 21, 2021 1 hour ago, bbest said: Next generation of replacement C2M1000170D is https://www.wolfspeed.com/1700v-silicon-carbide-mosfets?gclid=CjwKCAjwhaaKBhBcEiwA8acsHIXAWPUxDjNOkcr759hHaI2oBqpaPVCLSMR1UxDcq8RTelBzV8daMhoC110QAvD_BwE Power Dissipation 520W mmm... I’m pretty sure that is the same old generation.
audiostar Posted September 29, 2021 Report Posted September 29, 2021 On 9/21/2021 at 8:57 PM, bbest said: Next generation of replacement C2M1000170D is https://www.wolfspeed.com/1700v-silicon-carbide-mosfets?gclid=CjwKCAjwhaaKBhBcEiwA8acsHIXAWPUxDjNOkcr759hHaI2oBqpaPVCLSMR1UxDcq8RTelBzV8daMhoC110QAvD_BwE Power Dissipation 520W Sadly, that C2M0045170D isn't available as well...
johnwmclean Posted September 30, 2021 Report Posted September 30, 2021 yeah... that part is rated 72 amps and $83.85 a piece.
bbest Posted September 30, 2021 Report Posted September 30, 2021 10 hours ago, audiostar said: Sadly, that C2M0045170D isn't available as well... as I understand C2M1000170D differs from all of them: Quote High Speed Switching with Low Capacitances Ultra-low Drain-gate capacitance Yes, C2M1000170D is not so powerfull but those features may be more important.
audiostar Posted September 30, 2021 Report Posted September 30, 2021 I am using the C3M0350120D as a replacement part for the C2M1000170D in the GRHV in my CFA Electrostatic without any issues. But this part seems to be unavailable now as well. Remarkable how one needs to wait a year for parts now.
Sebtdi Posted September 30, 2021 Report Posted September 30, 2021 16 minutes ago, audiostar said: I am using the C3M0350120D as a replacement part for the C2M1000170D in the GRHV in my CFA Electrostatic without any issues. But this part seems to be unavailable now as well. Remarkable how one needs to wait a year for parts now. try Ebay for the 170D this is where I got mine this spring 1
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