Vintage Synth Repair

Trimmer adjustment turning , bad idea. 

There are four similar circuit boards on a dog house door, two on the inside two in the outside.  There is a socket-ed white LSI at right angle to the circuit board on each.  Each LSI handles 3 notes, CEF# etc. Remove and re-seat CEF#.  The LSI could be swapper with the board next to it.  All voltages can be compared to the board next door.   There are two zener diodes on each board two near the LSIs.  One voltage is -15volts and the other as I recall -7.5volts across.   If both zeners are correct and re-seating has not helped, there is a shorted signal diode. Check and compare with another board if value are suspect.


>________________________________
>From: "nanodocl@..." <nanodocl@...>
>To: vintagesynthrepair@yahoogroups.com 
>Sent: Thursday, September 5, 2013 7:12 AM
>Subject: [vintagesynthrepair] RE: Re: Hammond piper
> 
>
>
>  
>I did check almost every component, surely I am missing something.
>Thanks for sending the schematics. I really appreciate Nicolas.
>
>
>Nano
>
>
>--- In vintagesynthrepair@yahoogroups.com, <vintagesynthrepair@yahoogroups.com> wrote:
>
>
>Hi,
>
>You probably have some leaky transistor or leaky caps in the solo circuit.
>I'm gonna scan the pages related to that section and I'm gonna send them to you this weekend.
>
>Nicolas
>
>--- In vintagesynthrepair@yahoogroups.com, Nano <nanodocl@...> wrote:
>>>
>>> Hi Nicolas,
>>> 
>>> I think I found the model number, is the autocord 730.
>>> 
>>> Nano
>>> 
>>> El 03/09/2013 20:52, nanodocl escribió:
>>> >
>>> > Hi Nicolas,
>>> >
>>> > Thanks for your answer. The problem is when I turn on the solo 
>>> > instruments, a high frecuency note (E note) came out of the speaker 
>>> > (very soft, but anoying) without touching any key. I did try adjusting 
>>> > some trimers inside but no luck.
>>> >
>>> > By the way, I do not now excetly the model number It says "The piper" 
>>> > Autochord.
>>> >
>>> > Nano.
>>> >
>>> > El 03/09/2013 20:38, Nicolas escribió:
>>> >>
>>> >>
>>> >> What is the problem with your Piper?
>>> >>
>>> >> Nicolas
>>> >>
>>> >> --- In vintagesynthrepair@yahoogroups.com 
>>> >> <mailto:vintagesynthrepair%40yahoogroups.com>, "Nicolas" 
>>> >> <nico678@> wrote:
>>> >> >
>>> >> >
>>> >> >
>>> >> > Hi,
>>> >> >
>>> >> >
>>> >> > Yes, I have that service manual.
>>> >> > But I think there is a few different versions. The one I have is 
>>> >> for models 3100, 3200, 727 and 730.
>>> >> >
>>> >> > This is a pretty big manual. If you could tell me what circuits you 
>>> >> need I could scan them this weekend and send them to you by email.
>>> >> >
>>> >> > Nicolas
>>> >> >
>>> >>
>>> >
>>> >
>>> 
> 
>
>