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    voltage reading results are in, changed selenium,changed quad cap and driver board caps .

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    dmagazz

    Posts : 137
    Join date : 2018-06-20
    Age : 50
    Location : new fairf, ct

    voltage reading results are in, changed selenium,changed quad cap and driver board caps .

    Post by dmagazz on Fri Jun 29, 2018 5:37 pm

    ok so it looks like there was success right out of the ring putting all these upgrade/refresh parts in. thanks to great people on this forum who helped lead me in the right directions


    ODDBALL things i noticed-- i set the bias's to 1.56,(bios was set in the middle of the pot just about exactly where it was originally with the selenium rectifier)) tipped it back. got bios reading of 1.44. i was like  HUGH???... checked it again at the port,set to 1.56(it was only a tad off at 1.47) tipped it back again.. seemed  stable, but off by .02v high on the right.. that was wierd!..no?
    so i left it like that, wasnt gonna chase my tail for .02 volts

    OK..so
    for the rectifier the following- diode D544042R, (NTE552?), caps 2- 110v 100uf polarized, 4 10k 1-watt resistors(2 existing, 2 added)
    for the output capacitor - 80/40/30/20 525v dynaco quad cap
    for the driver board -
    4 - metal poly  0.1uf     600v  caps
    2 - metal poly  0.047uf  640v  caps
    2 - silver mica  82pf      500v caps
    2 - silver mica  390pf    1000v caps

    METER- JTR Instuments.--model DMM-300-
    I tested all volts for 100's in the 1000v position...all 10's in the 200v position and all 1's in the 20v position
    tested afyter warming up 20 minutes, with a 8 ohm 50 watt shunt on the speaker terminals,and shorted rca plugs on the inputs.
    now, what i have for readings.

    power into tranny from wall outlet, 118.5

    DIODE RECTIFIER- 55.2v ac in / 73v dc out

    DRIVER BOARD PINS
    3---378
    18--377

    QUAD CAP
    IN ORDER FROM 1-4 as in manual(1 being toward the back) LOOKING UNDER CHASSI
     1        2         3         4
    434----447----306----378


    TUBES
    _____PINS______1_______2_______3_______4_______5_______6_______7_______8__
    5AR4                            444                     367                     367                      444
    LF EL34            1.55      6.38ac     433        437         -30       -30        6.38ac     1.55
    LR EL34            1.55      6.39ac     432        435         -30       -30        6.39ac     1.55
    RF EL34            1.57      6.36ac     430        433         -29       -29        6.36ac     1.57
    RR EL34            1.57      6.38ac     429        432         -29       -29        6.38ac     1.57

    the amp is dead silent Smile
    but is there anything odd looking?

      Current date/time is Wed Sep 26, 2018 1:46 am