dont know the size of the input output trannies of
the simmonds sde
im only going on experience with linear
supplies
with power regs the higher the input voltage the
higher the temp of the reg but also the higher the voltage the better the
regulation
it is always a best practice to have a minimum of
3volts over the specified regulated voltage output
so the regulator can work properly and regulate
properly
----- Original Message -----From: jammieSent: Monday, May 07, 2012 3:57 PMSubject: Re: [vintagesynthrepair] Re: Simmons SDE
they are a thin square strip for the back of the power regulatorand a small thermal plastic washer with an internal raising that sits inside the hole of the power regtheres a hole in this for a 3mm screw the hole in the reg is 4mmso the rased 4mm insert on the 5mm washer fits the 4mm regulator hole the 3mm screw fits throught the 3mm hole so that there is a 1mm insulation gap from the reg then the thermal strip wich is about 0.5mm thick sits behind the regulator against the heat sink or chassis this insulates the reg from chassis you then clamp it up tight to get good thermal contactyour measureing the input the input can be upto 18v depending on the psu transformer used if a 240 to 36vac secondary is usedthen it goes through a bridge rectifier circuit which makes it dc with the filter caps for ripple then this unregulated supply goes to the power regs which regulate the supplyread the service manual it will tell you the exceptable voltage for input and output and the ripple percentage allowed before service----- Original Message -----From: Christian OnckenSent: Monday, May 07, 2012 2:50 PMSubject: Re: [vintagesynthrepair] Re: Simmons SDEvery strange.. I'm pretty sure the ICs were not insulated from the heat sink when I opened it up. So either they weren't in thermal contact with it with a very small gap, the heat sink compound acted as an insulator, or there were little insulators in there that slipped out when I took it apart.
So I measured the power supply outputs again with the power supply disconnected and found 16v on what I'm pretty sure is supposed to be the 6v output leg of the 7806. I swapped the 7806 out for a new one and the voltages were the same. Any idea what could be causing this?ThanksChristian