Just got my boards today. Noticed that the silk screen for C1 is mirror-imaged, a very minor issue. Boards look great!
The bill of materials shows PSU board Q3 as 771-2N7002PW-115 which is a really tiny SC-70 package. I dropped a SOT-23 on the board and it fits perfectly so I think the 2N7002 should change to part number 771-2N7002BK215.
I agree about the 68pF part changing to either polypropylene or ceramic NP0.
It looks like BC846C and BC856C will mount to the pads for Q8-Q11 on the amp board perfectly on the bottom side of the card. Q20 also looks good. This is an alternative to struggling with sources for BC556C. On the PSU card Q6 and Q7 leads are in a line so the fit is not as good for a bottom side SOT-23.
The bill of materials shows PSU board Q3 as 771-2N7002PW-115 which is a really tiny SC-70 package. I dropped a SOT-23 on the board and it fits perfectly so I think the 2N7002 should change to part number 771-2N7002BK215.
I agree about the 68pF part changing to either polypropylene or ceramic NP0.
It looks like BC846C and BC856C will mount to the pads for Q8-Q11 on the amp board perfectly on the bottom side of the card. Q20 also looks good. This is an alternative to struggling with sources for BC556C. On the PSU card Q6 and Q7 leads are in a line so the fit is not as good for a bottom side SOT-23.
I would not beat yourself up on not getting the E version. What you should not do is mix suffixes.
846 C and 856 C versions are also ok.
It would be quite easy to mod the PCB for SMD parts, but generally I get the feeling most people try to avoid them. I am quite comfortable using them- you just need a decent iron with a fine tip and 1mm or less solder wire.
846 C and 856 C versions are also ok.
It would be quite easy to mod the PCB for SMD parts, but generally I get the feeling most people try to avoid them. I am quite comfortable using them- you just need a decent iron with a fine tip and 1mm or less solder wire.
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Re the 68 pF cap - yes I agree it will be more economical and quite ok to go for polyprop or NPO.
I have a whole pile of Silver Mica's collected over the last 10 years or so, so that why this ended up on the board and in the BOM. I'll also make the changes and correct the silk screen error you noted Bill_P when I update the doc.
I have a whole pile of Silver Mica's collected over the last 10 years or so, so that why this ended up on the board and in the BOM. I'll also make the changes and correct the silk screen error you noted Bill_P when I update the doc.
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Agreed. Not sure if I am getting my message out... I would be satisfied with two complementary parts, both D or both E, but they are not available in both D or both E grade. One is available only as D, the other one is available only as E.
That is all. Only D for one part, and only E for the other part. We can't get KSA1381D/KSC3503D, nor can we get KSA1381E/KSC3503E as a pair.
If you can find them in small quantity at a reasonable price. If I wanted to buy a reel, the PDTA115 would be available too.
Btw, the 2.7K 1/2W CF602K70 resistor is non-stock/reel only.
edit: Did you intentionally specify R9, 3.3R as WW (wirewound)? The Mouser p/n 594-5083NW3R300J seems to be 2W metal film.
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"edit: Did you intentionally specify R9, 3.3R as WW (wirewound)? The Mouser p/n 594-5083NW3R300J seems to be 2W metal film."
Let me check this when I am back home.
E and D thing - ok clear.
I am wondering if there are any other TIS devices we can use. It's really a bummer that these things are not available with the same grade.
Let me check this when I am back home.
E and D thing - ok clear.
I am wondering if there are any other TIS devices we can use. It's really a bummer that these things are not available with the same grade.
I wonder if Chip 1 Stop might not have something
2sa1381 search result?[en] shopping site of electronic components and semiconductors- chip one stop
Japanese distributor bought out by IIRC Arrow. But they do have quite some stuff from Japanese vendors
2sa1381 search result?[en] shopping site of electronic components and semiconductors- chip one stop
Japanese distributor bought out by IIRC Arrow. But they do have quite some stuff from Japanese vendors
I found original Sanyo 2SC3503 E rank, and Fairchild 2SA1381 with unmarked hfe rank from local distributor - probably very old stock. I was disappointed at first when I saw unmarked Fairchild and intended to disregard them but when (weeks later) I measured hfe (for 10 each that I bought):
2CS3503E hfe 177-200
2SA1381 hfe 187-207
Unmarked Fairchild has even higher hfe (on average) than selected Sanyo! Can I use these? The only drawback is that these are in nonisolated case (unlike KSA/KSC).
Ampslab has 3502E/1380E but I guess they can also be used!
2CS3503E hfe 177-200
2SA1381 hfe 187-207
Unmarked Fairchild has even higher hfe (on average) than selected Sanyo! Can I use these? The only drawback is that these are in nonisolated case (unlike KSA/KSC).
Ampslab has 3502E/1380E but I guess they can also be used!
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No it shows up just fine...Is my post #243 invisible or what
1) I do not know how close or how different those parts are from the Fairchild SA1381/SC3503.
2) At $30/10 pairs, they are expensive. Perhaps that is a good deal at this point, but I can't tell. I was hoping someone else who knows better would comment. These are likely to be "surplus" parts, judging from the bent legs, which may mean they work, but were rejected during test.
3) Same thing applies to the parts Ivan found, seems like a good find, but I personally can't tell.
I will try to go back to my original source, and see what the actual cost would be by the time we take shipping into account. Those KSC3503E parts were originally purchased from a major distributor, and definitely from Fairchild. Still on tape as far as I remember what I was told. We could then buy the still available KSA1381E from a distributor like Mouser. We would presumably have a complementary pair, same parts that Andrew tested with, and for less per pair than AmpsLab. Just FYI, to get those parts to me, requires shipping them twice, so that is a week-8 days.
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Ampslab offer 1380/3502 is here:
2SC3502 2SA1380 SANYO - Buy Online @ AmpsLab
These parts are even better than 1381/3503 but the price is too high. I think that PMI's suggestion is better: KSA1381E from Mouser at low price and than mix them with hard to find and more expensive KSC3503E from different source.
2SC3502 2SA1380 SANYO - Buy Online @ AmpsLab
These parts are even better than 1381/3503 but the price is too high. I think that PMI's suggestion is better: KSA1381E from Mouser at low price and than mix them with hard to find and more expensive KSC3503E from different source.
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2.7K is not a standard 1% value and that causes the issue. There are other examples of this on the bill of materials. I chose 2.67K to replace 2.7K, Mouser part number 660-MF1/2CC2671F. Other 1% vs. 5% standard values: 5.6K - 5.62K, 3.9K - 3.92K, 22K - 22.1K, 330K - 332K, 22 - 22.1. Those are from the PSU board.
Resistor E Series - E3, E6, E12, E24, E48, E96 Tables :: Radio-Electronics.Com has charts of standard resistor values. E24 is for 5% parts and E96 for 1%.
Thanks, I did find some of those, but I did not know which were standard 1% values.
Thanks, if they are better, then someone besides me will have to make the call on what to use, and why. I think I am out of my depth here. Knowing why, would help, I think.
Many manufacturers make 1% tolerance resistors in E24 series.
Very few retailers stock E48 or E96 values.
You will find some retailers stock precision resistors in E96 values to a tolerance of +-0.1%
There is nothing wrong with stating E24 values, if they suit the circuit and certainly nothing wrong with choosing +-1% or +-0.5% or +-0.25% or +-0.1%
Very few retailers stock E48 or E96 values.
You will find some retailers stock precision resistors in E96 values to a tolerance of +-0.1%
There is nothing wrong with stating E24 values, if they suit the circuit and certainly nothing wrong with choosing +-1% or +-0.5% or +-0.25% or +-0.1%
Good question, I never noticed that. If nobody else has a comment, I will look into it. Have you been following the component discussion? I still do not have a 100% complete BOM that reflects some of the recent suggested substitutions...I got my boards, Thanks Peter
U2 in the board is PTDC143ET but in BOM it's PTDC144ET, is it ok to use any of them?
2SC3502 and 2SA1380 are for Ultrahigh definition CRT and very similar to 2SC3503/2SA1381 which are for High definition CRT. 3502/1380 have lower voltage rating (200V) but same current rating (100mA). Cob is even lower than 3503/1381, making it ultra ultra-low. Process is different, FBET (for 1381/3503 it's MBIT), but I don't know what that means and how important it is.
PMI,
I haven't looked at the component values yet but am supposing that most of the resistors are 1/4 watt rating? If so I have purchase kits of resistors in 1% from Ebay that were very inexpensive and I think that they were E48 or E96 values. Take a look perhaps I was just lucky at the time I found them.
Steven
I haven't looked at the component values yet but am supposing that most of the resistors are 1/4 watt rating? If so I have purchase kits of resistors in 1% from Ebay that were very inexpensive and I think that they were E48 or E96 values. Take a look perhaps I was just lucky at the time I found them.
Steven