EHHA Rev A - Interest Thread
Sep 24, 2010 at 7:52 AM Post #586 of 1,752

cobaltmute

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The CMF55 = RN55.  They are the same part, but CMF is industrial and RN is military.  They de-rate the military part, but as the CMF datasheet says:
Quote:
Except for marking, the Industrial and Military versions are exactly the same. Depending upon stock, military marked parts may be supplied as industrial rated parts

 
Sep 24, 2010 at 10:10 PM Post #588 of 1,752

jdkJake

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Let's talk tube LED lighting.
 
I know not everyone is a fan of doing it, but, I think it is kinda cool. I like it better than a boring old power-on LED staring at me. Particularly with these low power tubes that have very little heater glow. In any case, I did not use the standard LED specified on the BOM for the tube lights. Rather I went with a high mcd 3.3V/20mA LED to light things up. While I am not a fan of the color I selected (which I am going to change), I do think it worked out quite well. Note, this required a resistor change as well. I calculated a 1.33k was needed at a little over a 1/2W of power dissipation. While I though this would present a challenge, I found that V/D has a series of resistors that are rated from 1/2W to 1W. They are also perfectly sized for the board (think 1/2W package rated to 1W). Very nice. Very convenient.
 
http://www.mouser.com:80/ProductDetail/Vishay-Dale/CCF601K33FKR36/?qs=sGAEpiMZZMu61qfTUdNhG8UAagspIdBMBJQY5ou0K8I%3d
 
Anyway, just another option to consider as there are a lot of high mcd LED's at 3.3V/20mA available from numerous places (Mouser, Beezer, etc...).
 
Sep 25, 2010 at 12:25 AM Post #590 of 1,752

ujamerstand

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...and I missed c8. Well, mine is too big. This is what I get for only buying the difference in parts between the EHHA I and EHHA rev.A BOM. This reminds me; on the current BOM, the part number for R1 and R3 is swapped with R2 and R3 on the ps tab. It also needs the lead spacing measurements for C2, C3 and C8. which are 5mm and 2.5mm respectively. The C2 and C3 part listed on the BOM has 3mm lead spacing, but could be easily bended to suite.
 
Sep 25, 2010 at 8:24 AM Post #591 of 1,752

runeight

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Good catch on the resistors. I've got those fixed.
 
For the caps though, they are mica caps, but their board imprints are larger than the caps. I did this to leave a little more room for alternative caps here. And so I left out the lead spacing in the BoM.
 
The BoM caps should fit with just a little lead bending.
 
Sep 25, 2010 at 10:21 AM Post #592 of 1,752

jdkJake

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Ujamerstand,

If you want, I have extras on all of the parts, including those resistors and the cap you need. Make a list of what you need and PM your address and I will drop them in the mail to you.
 
Sep 25, 2010 at 5:43 PM Post #595 of 1,752

ujamerstand

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I'm hoping to have everything running some times the week after, as I try to find fuse holders and appropriate fuses locally this week. A trip to Active surplus it is!
Quote:
Ujamerstand,

If you want, I have extras on all of the parts, including those resistors and the cap you need. Make a list of what you need and PM your address and I will drop them in the mail to you.


Thanks for the offer jdk! The only thing that I have that doesn't fit on the new board is c8. Since its optional I think I'll just bypass it with resistor lead and be done with it. I'll return to it in the next mouser order. Let's see if leaving c8 out causes an trouble.
 
Sep 25, 2010 at 7:10 PM Post #597 of 1,752

jdkJake

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Thanks for the offer jdk! The only thing that I have that doesn't fit on the new board is c8. Since its optional I think I'll just bypass it with resistor lead and be done with it. I'll return to it in the next mouser order. Let's see if leaving c8 out causes an trouble.





Okay, let me know if you change your mind.

BTW, I am running a 2A fuse. I figure at a max draw of 1.8A with the sumr, that should be just about right.

Speaking of which, I got word from Richard Sumr. They were running behind on the epoxy process. Hopefully it shows up sometime this week.
 

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