Inu

http://www.digikey.com/product-detail/en/SCT2450KEC/SCT2450KEC-ND/4171678 Lower Ciss.

2SC1815 ECB 2SC2705 ECB 2SC4686A BCE 2SA1968 BCE

I have one extra KSA5 board and FETs.

Buzzing noise when adjust VR1(2K) toward the R33 side. So I set VR1 wiper to R32 side to avoid buzz noise at the beginning. Both VR1 and VR2 affects voltage of Active battery but VR1 affects much less. I have no benefit from adjusting VR1 so I replaced VR1 (2K) to fixed 2K ohm register and center(Q17 Base) connected to the R32 side. And changed VR2(10K) to 9.1K fixed resistor with 2K pot. After replaced these, no more intermittent static noise when amp is heats up https://picasaweb.google.com/inuponken/T2#5566996623938911634

I am in for one. 14 to go?

Silkscreen on the original board = I think R4 is 562 not 750.

Thank you.

I only confirmed with Sine wave… I’m used 2SA1930/2SC5131 and my friend used MJE15031/15030 for the power stage. We will compare sound after finish casing. https://picasaweb.google.com/inuponken/KSA5#5894178191153371122

Thank you. When set Ic to 62.5mA@22V, surface temperature is down to 122F (50℃) Total current = +22V 400mA (with current to the Relays) / -22V 380mA

What is the current draw in each output transistor on the original unit? When I set it for 100mA, 1.5inch heatsink gets really hot.

I am replacing these to 2SA1930 and 2SC5171.

4.7uF 63V WIMA = 6pcs 2 ohm (3W) = 71-cpf3-f-2

K216/J79/2SA1486 in my T2 and 2SA1967/1968LS in my KGSS are all from SATO Denki.

2SA1807 http://www.digikey.com/product-detail/en/2SA1807TLP/2SA1807TLPCT-ND/1782365

2SA1486 is on the “1985 NEC New Product Info” Picture is not 2SA1486 but the one from my old collections (30+ years old). NEC changed their logo in 1992 but they never used simple character logo on their products. https://picasaweb.google.com/inuponken/T2#5829408747652314498

Zettler 24V Relay A2830-2C-24DS http://www.bgmicro.com/REL1086.aspx MPS8099 and 8599 (0.15) http://www.bgmicro.com/TRNMPS8099.aspx http://www.bgmicro.com/TRNMPS8599.aspx It is hard to pairing MJEs… MJE15030G(NPN) Lot:AFA50 hfe = 78 78 80 83 96 97 98 104 104 105 107 109 111 114 MJE15031G(PNP) Lot: AFB09 hfe = 228 234 238 241 242 252 253 257 260 262

Schematic: Q2(Q7) Collector - Q12(Q13)Base Board: Q3(Q8) Collector - Q12(Q13)Base IN2 only (IN1 is OK) Schematic:Q14,23&24 MJE15030 Board:MJE15031 Schematic:Q25&26 MJE15031 Board:MJE15030 +/-22V line (or +/- 21V?) 4.7uF/63V are not on the schematic Q27 Collector 0.1uF is not on the schematic

Sorry, you are right. 500R = 500ohm. 500 = 50ohm

I think R20 (Pot) is 50ohm.

I think arced between resistor and GND pattern...

I used AAVID Ultrastick for my T2. http://www.aavid.com/sites/default/files/products/interface/ultrastick.pdf#search='aavid%20ultrastick'

Congratulations!!!!

With snubber circuit?

Oops! CCS on top.

If you use 6.3V windings on the HV transformer and use a delay circuit for the 6CA7 heaters, you need to add Relay into the HV lines (secondary) instead of the 120v primary line...