That's fantastic!
BA312 replacement
- Thread starter bubhardy
- Start date
TupolevFan
Super Member
Here is the gerber file which anyone can use by going to JLCPCB.com and it will be really cheap to make a batch. now it is just about selection of smt transistors. There are some toshiba transistors, Rhom transistors but i suspect our plain vanilla fjv1845 (nothing but ksc1845) will work fine.
GrisPato
Super Member
When I watched this thread developing I had a feeling allready you would like to take it on!
TupolevFan
Super Member
Ohh and i forgot i need to attach actual schematic for one to be able to correspond PCB prints and components values( I mean Q1,Q2,Q3, and R1,R2,R3,R4). @Hyperion I know you have a good eye for error spotting. When you have time take a look at attach schematic PDF and see if i messed something up ( I am famous for that 
)) I mean if I made an error in schematic compared to what was presented by @Hipocrates
)) I mean if I made an error in schematic compared to what was presented by @Hipocrates
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TupolevFan
Super Member
Seemed to me as something that could be easily done in Computer software. Besides on perforated board it will look so so. But on factory made adapter it should look nice and price wise is nothing to talk about
)) It is cheap.
TupolevFan
Super Member
We could do another variant which might be a bit more expensive using this chip from "Analog devices" https://www.mouser.com/ProductDetail/Analog-Devices/SSM2212RZ-R7?qs=WIvQP4zGang/JsE6b4gfRA==
It is dual transistor array (matched pair). We do not need matched pair here but it is low noise device and seems very nice ( I never tried it) Will need 2 per adapter and 1 transistor will be unused of cause. Not sure if it worth it but just as an option.
It is dual transistor array (matched pair). We do not need matched pair here but it is low noise device and seems very nice ( I never tried it) Will need 2 per adapter and 1 transistor will be unused of cause. Not sure if it worth it but just as an option.
Done - no errors that I can see.
TupolevFan
Super Member
Thank you John. In this case there should be no issues with gerber.Done - no errors that I can see.
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GrisPato
Super Member
Seemed to me as something that could be easily done in Computer software. Besides on perforated board it will look so so. But on factory made adapter it should look nice and price wise is nothing to talk about
For you yes, I would not now where to start. I remember as one of the first threads I read on here that you made an adaptor for installing smd bjt's to replace the dual 2sa798. And I think to remember a power supply board for an AU x17. Always interesting.
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TupolevFan
Super Member
By the way that 417 works @ my friend's house daily. So for now the bottom line is : if you need cheap BA312 replacement. Take my gerber ( in zip format). Register @ jlcpcb.com ( i have no affiliation with them what so ever). When you do "Order now" or may be "order" you will be asked to upload gerber file(or there will be option to do so). Just upload that zip file and you done. It usually takes about 2 weeks door to door for me.
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TupolevFan
Super Member
Thanks a lot.Nice work!!
On a separate note I got 3K of fjv1845E (same as KSC1845E but in smt ) from Rochester Electronics ( it was 100 USD only) if anybody interested i could share
I was hoping @TupolevFan would chime in!
I recall seeing threads where you had already made an SMT version.
I was thinking of a through hole version, to ease assembly for those who didn’t feel comfortable with SMT. Also, for those that want to keep the gear as close to original as possible. I’m going to put something together using TH parts that many of us have for repair/restoration already.
I have been kind of tied up the last two weeks. My wife’s mother fell ill, and passed away this last Monday, September 27. So we had to travel from our home in Michigan to the beautiful mountains of Western Maryland, for this. Very emotional and stressful time.
I recall seeing threads where you had already made an SMT version.
I was thinking of a through hole version, to ease assembly for those who didn’t feel comfortable with SMT. Also, for those that want to keep the gear as close to original as possible. I’m going to put something together using TH parts that many of us have for repair/restoration already.
I have been kind of tied up the last two weeks. My wife’s mother fell ill, and passed away this last Monday, September 27. So we had to travel from our home in Michigan to the beautiful mountains of Western Maryland, for this. Very emotional and stressful time.
Hi, what are you using to connect the adapter to the board? I'm assuming it's a 7-pin header of some sort, but did you have anything specific picked out? Do you have any of these completed? I'm curious what they look like.
TupolevFan
Super Member
Here is Through the hole version of BA-312 No smt!!! components size is 20mm(lenght)X 16mm(height). I used triangular pattern for transistors so anyone could install transistors of their choice ( ECB, EBC, BCE, BEC etc...
)). Here is the gerber file, Schematic is the same as previously attached. One needs to be aware that this version will be bulky as transistors will hangout from the side and to make overall profile smaller one will need to push transistors all the way to the board as much as possible.
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TupolevFan
Super Member
Nope. To be honest it is very primitive. I use what ever is left from the leads of the components i cut .
TupolevFan
Super Member
You can use gerber viewer to see how those are going to look. Register on JLCPCB and upload my zip file (gerber) and it will show you
TupolevFan
Super Member
Here is how the last one looks
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TupolevFan
Super Member
And here is the look of SMT version
TupolevFan
Super Member
@EastPoint Because i used primitive way to connect the leads I was not very precise with the distance between the holes. However it can be adjusted and adapted to the connector of your choice, I just did not explore the options and created something quick.