Mike Reed's Grandee Problems

[bnelson218]

hello, the thump your talking about only happens upon turning off or sometimes turning the organ on.its called transient sutdown tump.its not i big deal.most concords and grandees do it .mine concord does it and so does my hammond elegente.the sound comes from the power supply.ther is some teck info about this ,but you have to change a lot of components inside to make it stop doing that . to me its not a big thing. terry

I'm surprised these models aren't protected from the transient surges. I know that X77s are. The thump heard in the speakers is typically caused by the quick build up of the power supply (when the organ is turned on) and the likewise quick discharge of the supply caps (when turning the organ off). You don't notice any thump in tube-based equipment due mainly to the rectifier tubes that gradually build up the supply voltages as they heat up. To avoid this in the X77s, there is a delay circuit controlling a relay that connects the speakers to the amplifiers after the supply voltages are achieved. Severe thumps can cause damage to a speaker over time and such a delay circuit is pretty simple to build and install. I have a schematic for one if anyone's interested.

[Momboc]

Which connector should be cleaned?

[Larrytow]

That one right there !

[tpappano]

“Those” connectors 8)

[Daniel777]

I've got a one owner Grandee here in the south east UK, all working I think!

I've cleaned it up and tested everything

Anyone like it? For a donation. Could deliver in van during the next week....

[gunnarhk]

Re-seating all the connectors and IC chips in their sockets might solve this problem for a good while - it helped my Elka X705 which had similar issues.