Search:

Type: Posts; User: robgrif; Keyword(s):

Page 1 of 2 1 2

Search: Search took 0.03 seconds.

  1. Replies
    59
    Views
    8,847

    ok no limiter still 3vdc on speaker output

    ok no limiter still 3vdc on speaker output
  2. Replies
    59
    Views
    8,847

    ok preamp and tube section hooked up new...

    ok preamp and tube section hooked up
    new measurements
    q5 and q8 g-52v d+3v s -52v
    q4 and q11 g+50v d+3v s +52v
    q6 be .6v
    q7 be .5v
    speaker output +3vdc
  3. Replies
    59
    Views
    8,847

    no pulsing in light. board in chassis. preamp /...

    no pulsing in light. board in chassis. preamp / tube circuit are not hooked up .I will re-connect those items.
  4. Replies
    59
    Views
    8,847

    sorry for confusion of that statement . the base...

    sorry for confusion of that statement . the base emitter voltage on q6 and q7 is not static it is constantly changing
    from approx .9 v to approx 50v it is not staying at any particular voltage....
  5. Replies
    59
    Views
    8,847

    ok the amp voltages are q6 B -04.2 V C -44.6 V...

    ok the amp voltages are
    q6 B -04.2 V C -44.6 V E -3.5 V BE RANGING .9V TO 50V
    Q7 B +3.4 V C 45 V E 3.0 V BE RANGING .5 V TO 50 V
    Q4 G +45 V D -43 V S +48 V GD +88V GS -4V
    Q11 SAME AS Q4...
  6. Replies
    59
    Views
    8,847

    ok thanks probe + on emitter - on base q6=+.6 v...

    ok thanks probe + on emitter - on base q6=+.6 v probe +on emitter - on base q7 = -.45 v
  7. Replies
    59
    Views
    8,847

    ok removed limiter 1 amp fuse no speaker 3.5...

    ok removed limiter 1 amp fuse no speaker 3.5 volts dc on output terminals this does not change with bias adjustment fuse blew while I was adjusting bias. installed new one amp fuse . still 3.5 volts...
  8. Replies
    59
    Views
    8,847

    Okay hi all parts arrived put in 4 new mosfets....

    Okay hi all parts arrived put in 4 new mosfets. The amp is working on limiter right now. Bulb is dim. Measuring 1.0 volts dc on speaker output. Preamp output working.touched. Small 8 ohmns speaker to...
  9. Replies
    59
    Views
    8,847

    ok thanks will return as soon as new parts arrive...

    ok thanks will return as soon as new parts arrive
    happy thanksgiving to all those celebrating
  10. Replies
    59
    Views
    8,847

    thanks for all input lots of thought thanks...

    thanks for all input lots of thought thanks
    anyway i think JAZZ p Bass is on to something about the limiter upsetting things. put new mosfets in 60 watt limiter glowing bright .Installed preamp...
  11. Replies
    59
    Views
    8,847

    thanks for the info . all those gate diodes test...

    thanks for the info .
    all those gate diodes test good . all the outputs were changed as were pre-drivers and were good. all resistors test good correct ohmns readings. the preamp board is not...
  12. Replies
    59
    Views
    8,847

    ok installed fuse it blew also both mosfets q5...

    ok installed fuse it blew also both mosfets q5 and q8 blew as well oops fuse was 2amp my bad
    any way this is the same problem originally so whatever it is remains a mystery i will purchase two new...
  13. Replies
    59
    Views
    8,847

    ok thanks something strange is happening.when the...

    ok thanks something strange is happening.when the emitter of q7 is touched with + probe from meter light limiter dims amp starts to hum and dc on speaker goes to -47 volts. i have two meters this...
  14. Replies
    59
    Views
    8,847

    thanks checked the resistors they are all...

    thanks
    checked the resistors they are all correct values and good
    as for q6 and q7 not sure what is happening there.
  15. Replies
    59
    Views
    8,847

    [QUOTE=The Dude;367281]It would appear from your...

    [QUOTE=The Dude;367281]It would appear from your measurements that Q6 and Q7 are open. Also check R41, R43, R58, and R67.[
    ok checked those resistors all good
  16. Replies
    59
    Views
    8,847

    ok thanks here are the values that I got Q7...

    ok thanks here are the values that I got
    Q7 E=+.06 v C=+18v B=+3.16v
    Q6 E=-.06 v C=-18v B=-2.6v
    Q3=E 2.6v C=3.16v B=1.5 v
    U3 ouput = 0v
    light bulb limiter 60 watt bulb
  17. Replies
    59
    Views
    8,847

    ok replaced power supply caps one was causing...

    ok replaced power supply caps one was causing more current to flow when touched.still drawing excess current. would it be possible for U3 to be causing this problem.?just guessing now.
  18. Replies
    59
    Views
    8,847

    Sorry wrong meter scale. Reading is 49.5...

    Sorry wrong meter scale. Reading is 49.5 milivolts dc . On. 33 ohmns resistors
  19. Replies
    59
    Views
    8,847

    20.7 @source q8 20.8 source @q11

    20.7 @source q8 20.8 source @q11
  20. Replies
    59
    Views
    8,847

    There is 49.5 milivolts through them I tried to...

    There is 49.5 milivolts through them I tried to adjust it down but it did not go lower the bias pot measures 500 ohmns and responds to adjustment down to zero.
  21. Replies
    59
    Views
    8,847

    Okay replaced all those bits however amp still...

    Okay replaced all those bits however amp still pulling high current on light bulb limiter. Not sure what else could be drawing current power amp is only board hooked with nothing attached. The last...
  22. Replies
    59
    Views
    8,847

    the part is an in rush current limiter that...

    the part is an in rush current limiter that failed . identified by J.M.Fahey (thanks) it is an sl22 1000r .still passes ac to amp
    q5 and q8 removed 60 watt light bulb limiter showing low idle...
  23. Replies
    59
    Views
    8,847

    here is jpeg of power amp 31574 and power...

    here is jpeg of power amp 31574
    and power supply31575
    thanks
  24. Replies
    59
    Views
    8,847

    b200r

    thanks very much for advice and schematics.
    this amp failed about one year ago with same problem i think but ithought the cause was the incorrect factory board wiring of crossover
    is it possible...
  25. Replies
    59
    Views
    8,847

    thanks speaker not connected no ac at speaker...

    thanks speaker not connected
    no ac at speaker terminals
    btw acdc rocks
  26. Replies
    59
    Views
    8,847

    Ampeg B200R Bass Amp

    ok thanks for that . just going slow removed q8 . limiter 60 watt bulb barely glowing
    should i continue to remove other two mosfets
    would this be all that is wrong or could there be underlying...
  27. Replies
    59
    Views
    8,847

    b200r

    thanks for reply
    schematic does not show MOV it is on black supply line before fuse a piece of the device broke off when problem occured. also transformer has same wires as figure for export 240...
  28. Replies
    59
    Views
    8,847

    Ampeg B200R Bass Amp

    Hi All
    I have an Ampeg B200r Bass Amp with a problem
    Stopped working, speaker started humming seems to be drawiing excessive current MOV blew out and fuse was sparking but did not blow fuse The...
Results 1 to 28 of 50
Page 1 of 2 1 2