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Post by loupy31 on Aug 22, 2009 21:50:22 GMT
Hi Everyone, Ok I am slowly building my SCHA, I have found 2 small cases which will hold the power supply in one and the HA in the other, The JLH placement is my problem, It can fit in the power supply case but we are talking a VERY tight fit, Or placed in the other case with the HA PCB, which has more room. Will The JLH cause any issues being just above the HA PCB.
Regards Peter
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Post by Deleted on Aug 22, 2009 23:49:52 GMT
Hi Everyone, Ok I am slowly building my SCHA, I have found 2 small cases which will hold the power supply in one and the HA in the other, The JLH placement is my problem, It can fit in the power supply case but we are talking a VERY tight fit, Or placed in the other case with the HA PCB, which has more room. Will The JLH cause any issues being just above the HA PCB. Regards Peter Peter I don't believe there will be a problem, although you could always mount it on a piece of unetched copper PCB from Jaycar, and earth the copper side to the earth PCB pin on the HA Alex
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Post by loupy31 on Aug 23, 2009 10:53:49 GMT
Hi Guys, I have been doing some work on the JLH board, I noticed that on some pic of this board the 639 transistor is on the same side as the 1930's but on diferent pics the 640 is there and the 639 is next to the 5171's. which is the right way?
Regards Peter
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Post by Deleted on Aug 23, 2009 11:42:43 GMT
Peter
Other than the optional current limiter device, ALL the transistors for the +VE rail side are NPN devices. With the -VE rail side, ALL transistors are PNP devices. i.e. the +VE rail side uses BC639 and 2SC5171. The -VE rail side uses BC640 and 2SA1930. To confuse matters further, there were 2 main variations. The major difference between these ,was that the -VE and +VE rail sides were swapped, in a well meaning effort to have the terminals of the PSU PCB line up with those of the JLH PCB.
Alex
P.S. To assist with correct orientation of the 2SA1930 and 2SC5171, there are usually small letter "e" markings on the copper side next to a pin. The "e" stands for Emitter. The Toshiba transistors pin out, looking at the front (label) side, is Base, Collector, Emitter. The BC639 and BC640 ,looking at the front (flat side) with leads downwards, are Emitter, Collector,Base.
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Post by loupy31 on Aug 23, 2009 12:14:11 GMT
Hi Alex, Thanks for the reply, I had a good look at all the available pics and diagrams, its like you said. I think my enthusiasm needs to come down a notch..Look Before I leap.... Regards Peter
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Post by Deleted on Aug 23, 2009 12:16:20 GMT
Peter There was some further information added just as you posted. Alex
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Post by loupy31 on Aug 23, 2009 13:47:30 GMT
Thanks Alex, I double checked the orientaion of the transistors, All Is Now well. Once again thanks
Peter
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