GRonald
Active Member
They should not, are you getting a sound from the speaker on power on, before the relay clicks?.
I had to replace the transistors on the meter board in one unit that had that problem.
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Marantz 250 restoration query
- Thread starter quadmatrix82
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I had to replace the transistors on the meter board in one unit that had that problem.
No sound from speakers until the relay clicks amp runs well and holds bias at 12mv and offset is 0 but the meters completely peak hard on switch on?
All the transistors in the meter board have been replaced as has the zener diodes
GRonald
Active Member
so the wiring is ok and the transistors are new. Have you done the meter adjustment as per the service manual, if so that would mean the meter board is working fine.
I’ll take a photo of the wiring I believe it looks good and I did the calibration so assuming that’s ok too
Double checked the calibration it’s spot on here’s some photo of the wiring looks good to me ? Diodes on one side replaced with 1n270 as one of them was shorted previously…the resistors are getting super hot and show signs of previous heat issues also
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New development - I set the meters to the off position for both channels from the face plate but the meters still bounce hard on start up - any ideas on what the issue may be?
For future restorations I can confirm either 1n60 or 1n270 work well on the meter board for the mm8005 diode replacement
I have checked my 250 which was refurbed by Bob Speece, about 3 years ago.
My meters do bounce on startup. In fact, they do full bounce once, goto zero and bounce back up 50% before settling at zero. This is at startup after being off for a month or so. I've left it on, and I'll power cycle it maybe tomorrow and we'll see if the bounce is still there.
Full disclosure, I have one meter that doesn't always go back to zero, it's some stickyness in the meter.
My meters do bounce on startup. In fact, they do full bounce once, goto zero and bounce back up 50% before settling at zero. This is at startup after being off for a month or so. I've left it on, and I'll power cycle it maybe tomorrow and we'll see if the bounce is still there.
Full disclosure, I have one meter that doesn't always go back to zero, it's some stickyness in the meter.
Thanks for checking, this sounds exactly like what mine does seems like it’s normal for these amps glad we have clarified it for us and anyone else who restores these in future!