• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Deciding what caps to use

I picked up a nice SX-737 yesterday and am going to do this resto. Some questions:

Has the BOM in post #5 been kept fresh as parts have gone obsolete? There are edits to that post that suggest some updates, but later posts indicate some parts have gone obsolete and so may not be reflected in the BOM.

Is there a more/most current version of the BOM I'm not seeing?

Should I just paste the list into the Mouser web site and see what happens?

Thanks,
Mike.
 
cuda440 said:
Should I just paste the list into the Mouser web site and see what happens?
Click to expand...

When you use the BOM tool at Mouser, if there are parts they don't have it will suggest replacements. There is no downside to giving it a try.

What it doesn't do well is suggest replacements. Mouser's software does a fine job of pointing out is missing and suggesting general alternatives. The best next step is for you to do research and find better replacements for the ones that aren't available.

For instance, Mouser might tell you "we have no KSC1845F's in stock. we recommend using the KSC1815 instead." That is a very different transistor, different enough that you probably don't want to use it as a replacement. You'd want to find some other vendor who does have the 1845F.

Or Mouser might say "nope, we don't have any of the Nichicon KL 1uf 50V ecaps, so you could use the Kemet XX series 1 uF 50V instead". Here you'd want to do a little research to see if there was a KL series 1 uF that was higher voltage than what you were asking for. Bingo! Yes, Mouser has those and that what you should use.

So, using the BOM tool at Mouser even with an older BOM parts list from AK is an OK start. Just be prepared to do your own research, even coming back to a thread like this and asking "what now", for the parts from the AK BOM list that Mouser doesn't have in stock right now.
 
Keeping the lists fresh would be a career for someone, not a volunteer effort, The lists STARTED when I published spreadsheets of parts I had made over the years as I did restoration work on various models. Then they took on a life of their own.

Submit the LAST list in the thread, copy out all the parts lines that mouser DIDN'T recognize and post them. That'll give us a starting point to make the substitutions. Has to be the whole line so we can LOOK at that component position to make the best choice. Sometimes it's just a different suffix on the end of the parts list. That's mostly transistors.

Then once a list is fully updated and available, post a new version at the end of the thread. For the next person to start with.
 
Understood it would be a monumental effort to maintain the lists. I hope I didn't imply otherwise. I was just asking if I was looking at the most current version since multiple threads can address the same topic and one can easily miss the best one available.

In very my first resto (last year, of an SA-9500ii) I posted the BOM that I used, derived from the various posts on the topic. It took some effort to cross reference the posts and come up with the parts list for Mouser (though I never saw a mention of the Importer tool at the time, a nice timesaver). A good task for this newbie to take on as it was a great learning experience and perhaps a way to start paying my dues.

I'll have a go at what Mouser has to say about the BOM and report back.
 
Okay, the results are in.

All the film capacitors from Cornell Dublier (Mouser prefix 598) are obsolete. I found the Wima (505) equivalent.

Three of the Nichicons (647) were out of stock in bulk, but available on tape, so no problem there.

For some reason the Importer tried to choose a reel of Nichicon 1uF 50V and choked on the minimum order, but bulk is available.

Looks like On Semi (512) has a new mfg designation (863) and a new part number for the 1N5404 diode, it is 863-1N5404RLG.

The problem children are:
Mouser #: 512-KSC2073TU
Mfr. #: KSC2073TU
Mfr.: ON Semiconductor
Desc.: Bipolar Transistors - BJT NPN Epitaxial Sil
13 week lead time

Mouser #: 863-MJ21194G
Mfr. #: MJ21194G
Mfr.: ON Semiconductor
Desc.: Bipolar Transistors - BJT 16A 250V 250W NPN
26 week lead time!

Digi-Key has the KSC2073TU, but not the MJ21194G, though the lead time for the latter is a mere 18 weeks. Any suggestions on what to do here?

I have a working version of the Mouser BOM in a text file, with all the replacements listed, that I would like to share if someone wants to check my substitutions. You can't use it directly since there are entries with notes embedded, but I'll post a clean version once it has been vetted.

Thanks.
 
For the KSC2073 you should be able to use Mouser's in-stock KSC2073H2. It is the same transistor just a higher gain HFE which shouldn't matter in the power supply circuit. (All you super-smart people chime right in and correct me if I'm wrong).
 
For the output transistors, you should be able to use the MJ15003G, which are in stock, in place of the MJ21194G. It's what we're all having to do at the moment. Just buy your MJ15003G before they run out.

In a pinch, you can always post here and some kind AK'er with a big stash can help you out.
 
Thanks. I made the suggested changes and they look good. I have a new problem though, when looking for a replacement for

Mouser #: 598-DSF050J474
Mfr. #: DSF050J474
Mfr.: Cornell Dubilier
Desc.: Film Capacitors 0.47uF 50V 5%

I didn't notice the Wima equivalent is a non-stocked item at the 5% tolerance, but is available in 10%. I'm assuming 5% is required. They are used on the tuner and mic boards only.

Both Nichicon (647-QYX1H474JTP, $1.16) and Kemets (80-SMR5474J50J0416, $1.97) are available.
 
cuda440 said:
Thanks. I made the suggested changes and they look good. I have a new problem though, when looking for a replacement for

Mouser #: 598-DSF050J474
Mfr. #: DSF050J474
Mfr.: Cornell Dubilier
Desc.: Film Capacitors 0.47uF 50V 5%

I didn't notice the Wima equivalent is a non-stocked item at the 5% tolerance, but is available in 10%. I'm assuming 5% is required. They are used on the tuner and mic boards only.

Both Nichicon (647-QYX1H474JTP, $1.16) and Kemets (80-SMR5474J50J0416, $1.97) are available.
Click to expand...


You're doing a great job with looking up the replacements and dealing with the existing BOM. Keep it up!

Try this approach and see how it works for you:

You know you need a through-hole (not surface mount) film capacitor. You probably want a radial set of leads instead of axial ones (that's old gear, not the "modern" solid state gear like your 737). You know you want 0.47 uF and you need 50 VDC or more.

Try searching on Mouser using these sequential steps:

Passive components
Capacitors
Film caps
Through-hole
In-stock
Radial
0.47 uF

At this point, you should have LOTS of matching choices. Now is when you can start getting picky and use your own judgement or favorites.

I like Panasonic for this range of capacitance in film caps, so I limit the results to Panasonic.
You're really just interested in polyester or, maybe, polypropylene, so limit the results to polyester as the dielectric.

You should be down to about 25 choices, in stock, of Panasonic ECQ series film caps. All of them will be way more than 50V capable. If they aren't, filter to just show those 50V or higher.

Now you need to take into consideration just two things: lead spacing and physical size.

Look at your PCB, measure or guess at how far apart the holes for this cap are. They'll be 5mm or 12mm or maybe even 15mm. You want to choose a Panasonic ECQ series with lead spacing to match or nearly match your PCB holes. Remember you can bend the leads inward or outward, so you don't have to match this exactly.

Next, look at the width and physical dimensions. Nice caps like these Panasonics can get quite big, so even if your lead spacing is close enough to get the leads in the PCB< you might find the physical cap body is too big to fit in that spot on the PCB and not shove other nearby components out fo the way. So, just look at the physical dimensions listed on Mouser, lokk at your PCB where this cap goes, and get one that you think will fit. One or two sub-series, like the ECQ-B or something, says "smaller than normal" in the datasheet. I prefer those so I can avoid crowding when I choose replacement film caps.

Does that help? When you try the above or just the parts above that make sense, are you getting good choices in your search results?
 
Last edited:
Yes, that does help confirm my process. On the SA-9500ii resto last year, I had to sort through the various part update posts when I compiled the BOM and I ran into some of the same "not available" issues, so had to learn how to search for compatible parts. Once of the nice things about that BOM is that the lead spacing and physical sizes had already been worked out, so all I had to do was select from items that were vetted and available. I was hoping/expecting to do much the same this time.

Back then the highly regarded Pana ECQ series was no longer an option. I don't recall if it was merely due to them being out of stock or whatever, but the Wimas were what was recommended so I went with them.

I noticed you don't mention tolerance when choosing the film caps.
 
cuda440 said:
I noticed you don't mention tolerance when choosing the film caps.
Click to expand...

Well, that is an oversight on my part. I do care about precision (tolerance) when restoring. For film caps, anything better than 20% is ok and I shoot for 5%. I forget what the Panasonic ECQ-whatevers are, but it's better than what was in the gear in the first place.

When restoring something with ceramic caps or in the RIAA curve part of a phono stage, I use MLCC ceramic caps with C0G NP0 dieletric from Murata and TDK. Those are 5% tolerance. I'd love to go lower, but I don't find it worth the price of 1% caps.

For resistors, 1% precision and metal film is cheap, so that's what I aim for there.
 
cuda440 said:
Back then the highly regarded Pana ECQ series was no longer an option. I don't recall if it was merely due to them being out of stock or whatever, but the Wimas were what was recommended so I went with them.
Click to expand...

If I remember correctly, there were a number of BOMs with a Panasonic EC-something series that got discontinued. There are still plenty of Panasonic ECQ series to look at and in-stock at Mouser and digi-key.

WIMA's are fine, almost always smaller, but few of the ones Mouser carries have long leads that I normally need to get into the PCB holes. If you order the WIMA caps in TAPE or REEL packaging, you get the long leads version. Otherwise you get 2.5mm or so of lead and that's not enough for many situations.

Just my $0.02.
 
The MJ21195G and MJ21196G spec's compared to the 21193/94 are so close to be essentially the same. And they are slightly cheaper than the 93/94's.
 
There's a couple of bucks to be saved, so if the specs support it, I'll make the change.

I was thinking I might put the mica insulators on the list too, but I couldn't find them in the Mouser site.
 
No apologies needed and thanks so much for the links.

Is there a preferred way to format the BOM? I'm currently tracking as two text file versions, one with notes and one without, as the Mouser Importer won't like the notes, (yes?). It would be nice if I could just have the one version with notes and the Importer would know to ignore everything after a certain character (like a ";" perhaps), they way software compilers ignore comment lines. Alternately I suppose a spreadsheet file with columns for part numbers and notes would work too. I'm trying to make it easy for the next user to cut and past the list without having to strip out the notes line by line.

Also, I typically see this kind of info pasted right into the thread as another post, instead of as a separate file. Again, what is possible and what is best?

Thanks for all the help.
 
I just spotted in another post from MarkTF that excel spreadsheets are standard and I found one for the 737 dated 2016. Should have started there.
 
To do this right I'm going to have to print out everything and walk through it line by line, but my printer just ran out of ink so it will be a day or two.
 
You must log in or register to reply here.
Back
Top Bottom