Thanks everyone for the suggestions. Q2 did seem like the likely culprit since it wasn't operating (cold to touch). However, I thought there might be some things to check 'upstream'.
So I pulled Q2 out and it looks like it's dead. I did notice that the screw holding to the heatsink was slightly loose from thermal cycling I suppose. My theory is Q2 failed because of overheating; even though it was touching the heatsink there wasn't enough pressure to get adequate heat transfer.
No matching is required for these mosfets, correct?
So I pulled Q2 out and it looks like it's dead. I did notice that the screw holding to the heatsink was slightly loose from thermal cycling I suppose. My theory is Q2 failed because of overheating; even though it was touching the heatsink there wasn't enough pressure to get adequate heat transfer.
No matching is required for these mosfets, correct?
Pix here:
https://www.diyaudio.com/community/threads/the-diyaudio-first-watt-m2x.321925/post-5842624
I'm not sure it that's thermal damage on the back or just some goo from the transfer pad.
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After replacing Q2, double check and make sure that none of the pins have a connection to the chassis prior to power up. Recall Pin 2 is also connected to the back of the IRFP9240 P Channel MOSFET as such any break in the thermal insulator can compromise the FET.
The link to your build is extremely clean though so I am a little surprised with this infantile failure! I usually use aluminum thermal insulators like those from Aavid (type 4170G or equivalent) for these reasons.
Best,
Anand.
The link to your build is extremely clean though so I am a little surprised with this infantile failure! I usually use aluminum thermal insulators like those from Aavid (type 4170G or equivalent) for these reasons.
Best,
Anand.
Thanks Anand. I will get some of those aluminum oxide thermal pads. I'm really not sure if the pads I was using allowed a short circuit or the mosfet just got too hot because it wasn't pressing tightly against the heatsink. The screw was slightly loose in spite of having a lock washer. I may try a different type of lock washer such as a Belleville.
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Q1 on my L channel has died, have not taken it apart yet, is it OK to use ceramic insulators?
^Are you talking about pads similar to what's been recommended 3 posts back from yours? Those, yes.
With parts becoming harder to hunt down I decided to grabs parts for a future M2X now. So far I have tracked down most of the parts for the M2X amp boards, Ishikawa, Austin, Norwood, IPS6+7, and Cedarburg. The only thing I really can't find anywhere is C6 smd panasonic cap for Norwood.
https://www.mouser.com/ProductDetai...fhyjPdCoskQpxW1AxwIxaUMhgYUEbdnRoCf-gQAvD_BwE
Anyone know where a secret stash might be hidden or could make a reasonable suggestion for an alternate part? New to the SMD part game and even using the search matrix on Mouser/Digikey don't feel comfortable making a best guess myself.
https://www.mouser.com/ProductDetai...fhyjPdCoskQpxW1AxwIxaUMhgYUEbdnRoCf-gQAvD_BwE
Anyone know where a secret stash might be hidden or could make a reasonable suggestion for an alternate part? New to the SMD part game and even using the search matrix on Mouser/Digikey don't feel comfortable making a best guess myself.
Norwood's "C6" has four critical parameters that you need to match exactly, to ensure (a) it fits properly on the PCB, and also (b) it functions correctly in the circuit. I've marked those four parameters on the sales page of the Panasonic capacitor (Mouser part number 667-EEE-FT1H221AP ) from the Norwood BOM.
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Mark,
Thank you for pointing the significant parameters. Quick search with those on both Mouser and Digikey comes up empty, will keep digging though.
I will add, the Ship of Theseus Nimitz board was real kick in the pants to commit to building some M2X input boards. And look what showed up today when I got home:
Thank you for pointing the significant parameters. Quick search with those on both Mouser and Digikey comes up empty, will keep digging though.
I will add, the Ship of Theseus Nimitz board was real kick in the pants to commit to building some M2X input boards. And look what showed up today when I got home:
Those (plus Norwood) are the ones that receive the greatest amount of effusive & opulent praise here on diyAudio. You'll have a lot of fun with them!
re: EEE-FT1H221AP
The 'mini' 8mm diameter for the Panasonics and rough equivalents seems to be OOS in most of my usual places. I can't seem to find my spares, or I'd happily send you some. I have 8 'somewhere'.
If they turn up, I'll PM you. Good excuse to organize my SMD parts.I checked the pad dimensions and space around the part, but I came up empty when trying to look for something else (in stock) that might fit from other manufacturers. Others may have better skills, or perhaps can find some in their spares bins.
Last, but not least... TTI seems to have plenty of stock (>100k parts). Their MOQ is 500 for a standard order though. There is a special note to call them for the cut-tape MOQ of 10, so maybe you could get lucky. 😀
Cheers,
Patrick
Thank you for looking. I did some more digging last night using Mark's critical values and found something at Digikey that meets that criteria that while out of stock should be restocked in the next 2 months.
https://www.digikey.com/en/products/detail/panasonic-electronic-components/EEE-FT1H221GV/10290480
When I placed my order they showed enough restock to ship in 1 month, today its showing roughly 2 months. Ordered 10 to be on the safe side, so hopefully I'll have some extras to share if needed in the future.
Im ok with a 2 months wait time, still have an Aleph J and Aleph 30 to knock out first, just wanted to hoard all the parts given the shortages.
https://www.digikey.com/en/products/detail/panasonic-electronic-components/EEE-FT1H221GV/10290480
When I placed my order they showed enough restock to ship in 1 month, today its showing roughly 2 months. Ordered 10 to be on the safe side, so hopefully I'll have some extras to share if needed in the future.
Im ok with a 2 months wait time, still have an Aleph J and Aleph 30 to knock out first, just wanted to hoard all the parts given the shortages.
Hi everyone,
I'm starting to order the parts for an Ishikawa M2 and I'm having trouble finding a reliable seller for the Murata NP0/C0G caps (I live in China and counterfeits are everywhere). However, I've found Amtrans caps for the same values at a shop I trust.
My beginner question is: how important is it that the caps are NP0/C0G and ceramic, and why? What difference would it make if I went for the ones I found? (See attached screenshot of the datasheet)
Thanks for your time 🙂
I'm starting to order the parts for an Ishikawa M2 and I'm having trouble finding a reliable seller for the Murata NP0/C0G caps (I live in China and counterfeits are everywhere). However, I've found Amtrans caps for the same values at a shop I trust.
My beginner question is: how important is it that the caps are NP0/C0G and ceramic, and why? What difference would it make if I went for the ones I found? (See attached screenshot of the datasheet)
Thanks for your time 🙂
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Check whether Mouser has stock of NP0/C0G ceramic capacitors made by TDK .
If you can't get them in 5mm lead spacing, simply buy them with 2.5mm lead spacing and bend the leads yourself before stuffing and soldering.
If you can't get them in 5mm lead spacing, simply buy them with 2.5mm lead spacing and bend the leads yourself before stuffing and soldering.
