Hi Mooly, It is pretty difficult to get to those coils(L701) with out dismantling the P700 board, but what i did was I check the voltages, I did the audio adjustments on pin 804 and 805 i got the 35vdcm, when i did the adjustments on the P700 board i can adjust the left side to zero but the right side keeps fluctuating i can not adjust it when i turn the R707 it does not change the setting it deflexes between 0.015 and 0.10 can not adjust, What should i look for next???
Pat
Pat
Are you measuring this voltage on the PCB before the relay ?
You won't get any meaningful results measuring across the speaker outputs as it says in the manual because the relay hasn't closed due to the fault.
You should be able to get to some of the parts on the output line in order to make a definite measurement. What about on the junction of the 0.22 ohm resistors ?
Tbh
it sounds like this might be beyond what you are comfortable working with. To repair this is going to involve fairly complex measurements and probably replacement of parts, possibly altering the values of surrounding parts to work with modern semiconductor replacements.
You won't get any meaningful results measuring across the speaker outputs as it says in the manual because the relay hasn't closed due to the fault.
You should be able to get to some of the parts on the output line in order to make a definite measurement. What about on the junction of the 0.22 ohm resistors ?
Tbh
it sounds like this might be beyond what you are comfortable working with. To repair this is going to involve fairly complex measurements and probably replacement of parts, possibly altering the values of surrounding parts to work with modern semiconductor replacements.Attachments
Hi Mooly, I appreciate what you are saying, it's just I am very meticulous and I go over things a couple of times just to make sure i get it right, I know this is not a school and I really appreciate all the help i get from these threads.With all of that said, let me ask you this there are NO jumpers between the Main amp and the Pre amp with starting this should their be jumpers???
Pat
Pat
If you are seeing 35 volts on the main amplifier output point of that board then that is why the relay doesn't click.
The relay is to protect the speakers as much as anything. 35 volts would destroy them instantly.
Usual cause of a high DC offset would be failed output transistors and drivers. Why they failed would also need investigating. Could be abuse by a previous owner or it might be dries or an intermittent fault on the board.
The relay is to protect the speakers as much as anything. 35 volts would destroy them instantly.
Usual cause of a high DC offset would be failed output transistors and drivers. Why they failed would also need investigating. Could be abuse by a previous owner or it might be dries or an intermittent fault on the board.
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