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DYNA PAT

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  1. DYNA PAT

    Dynaco amp mods and tweeks

    Some pics from SCC catalog. My 416 Pat
  2. DYNA PAT

    Dynaco amp mods and tweeks

    Hi folks, New to this site but Ive attached a few articles you may find helpful. Did a pretty major upgrade to my SCC 1986 ST416 over the winter and included the PC-28 resistor mods discussed within. My 28 boards were the updated - doublesided version and I also replaced all caps - obtained from quo-co (Ed Fantasia) on eBay. Ed used to work for Dyanco / Hafler and is a wealth of knowledge - never a problem with his parts and he responds quickly to inquiries. My latest item I'm correcting is I had my right channel go out due to a shorted output transistor (Q5) I ordered a new set of transistors from Mouser - ON brand - 863-MJ21194G (8) and 863-MJ21193G (8) as old ones aren't available new and a couple other transistors exhibited some flakey readings (they are over 30 years old). new transistors have better ratings and heat dissipation characteristics. PC-28 boards do not appear damaged from checks performed. Revealed by right channel being out and one of the 4 relay board fuses being blown. Some pics from SCC catalog forthcoming. To date I've modified my unit (410 to 416 conversion dynakit as follows) Circa 1986: Replaced speaker relay with enclosed relay (on line kit) - Akitika.com RY301 (replace R142 with 1500ohm, 1W resistor to lower relay coil voltage) Replaced output (large) caps under relay board Akitika 22KUF80V Changed PC28 Caps and 6 resistors (ea) on PC-28 boards (R-28,29,30,31,32,33 to wire wound) (Mouser), new 1K trim pots (2 per board - PIHER 1K812M) (RP011 190103) "qua-co" on eBay (reliable) "Fantasia Audio" Installed led meters and select switch NOS Installed 2 speed fan thermo switch (KSD301) Rebuilt PC-30 board (all components) - lots of heat degradation (qua-co) eBay Installed short blue LEDs for power and hi-temp lights - 2152A6 NOS Lastly replacing all 16 output transistors as one failed (shorted) with MJ21193G, MJ21194G ON Semiconductor (8 ea) RCA input jacks with gold plated jacks Hope this helps others! Pat Dynaco Repairs For PC-28 Amplifier Boards copy.pdf DYNACO_REVIEWU.pdf Dynaco Stereo 400 Power Amplifier - Dead Channel Fix - Dynaco Repairs For PC-28 Amplifier Boards ~ Dons Deals.pdf
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