Wesley Talbot
New member
I ordered the HM 4.3 thermocouple PCB set and now I'm on the hunt for components. This is obviously difficult given current shortages, but I'm trying to do what I can. I'm also trying to buy from a minimum number of suppliers (primarily Mouser) to reduce shipping costs, so that adds some difficulty. I was hoping to get a bit of feedback on the following substitutions:
-Swap all 1/4W carbon film resistors with 1/4W 1% tolerance metal film resistors (I have these on hand but wasn't sure if there is an issue doing that in this application)
-Swap caps C4, C5, C6, and C12 standard parts all with Nichicon UHE1E101MED. I recall reading a 100u/25v cap could be used in all 4 of those places and this seems to be a good performing option with low ESR, plus it's in stock.
-Swap resonator Y1 standard part with CSTLS16M0X55-A0 - I think I read these have been used before?
-Swap MOSFET Q3 with IRFU9024NPBF - this is where things get iffy for me because MOSFETs have a bunch of specs and I'm not sure what's critical in this application.
-Swap DC Converter IC1 with Murata OKI-78SR-5/1.5-W36-C. Appears to be identical, but I'll need to re-solder a straight 3-pin header in.
-Swap power jack J9 with 694106301002 - dimensions look near identical so I don't anticipate any problems with this.
-Swap buttons S1, S2, S3, S4 with 430476085716 - again very similar if not identical to original spec parts (button is actually black, unlike the Mouser pic shows)
All of the above and most of the other required parts can come from Mouser, but I've still got to get my hands on an ATMEGA328P-PU. Appears that Jameco has that, so I'll probably have to order from there. Raspberry Pi's are also unobtanium at this point unless you want to pay a scalper, but I managed to pick up a lightly used RPi Zero W locally for a reasonable price, and all initial checks seem good on it.
Any opinions are much appreciated on the above substitutions! The MOSFET is what concerns me the most, so I'll go to another supplier for that if absolutely critical.
Thanks for the help!
-Swap all 1/4W carbon film resistors with 1/4W 1% tolerance metal film resistors (I have these on hand but wasn't sure if there is an issue doing that in this application)
-Swap caps C4, C5, C6, and C12 standard parts all with Nichicon UHE1E101MED. I recall reading a 100u/25v cap could be used in all 4 of those places and this seems to be a good performing option with low ESR, plus it's in stock.
-Swap resonator Y1 standard part with CSTLS16M0X55-A0 - I think I read these have been used before?
-Swap MOSFET Q3 with IRFU9024NPBF - this is where things get iffy for me because MOSFETs have a bunch of specs and I'm not sure what's critical in this application.
-Swap DC Converter IC1 with Murata OKI-78SR-5/1.5-W36-C. Appears to be identical, but I'll need to re-solder a straight 3-pin header in.
-Swap power jack J9 with 694106301002 - dimensions look near identical so I don't anticipate any problems with this.
-Swap buttons S1, S2, S3, S4 with 430476085716 - again very similar if not identical to original spec parts (button is actually black, unlike the Mouser pic shows)
All of the above and most of the other required parts can come from Mouser, but I've still got to get my hands on an ATMEGA328P-PU. Appears that Jameco has that, so I'll probably have to order from there. Raspberry Pi's are also unobtanium at this point unless you want to pay a scalper, but I managed to pick up a lightly used RPi Zero W locally for a reasonable price, and all initial checks seem good on it.
Any opinions are much appreciated on the above substitutions! The MOSFET is what concerns me the most, so I'll go to another supplier for that if absolutely critical.
Thanks for the help!