[sdiy] My Fancy Paperweight, the ESQ

[Rainer Buchty]

On Thu, 13 Aug 2009, Kyle Stephens wrote:

> Q1 MC7812CT - 6.25V (not a good sign)
> Q2 MC7812CT - 12.12V (ok)
> Q3 UA7805C - 4.93V (ok)
> Q4 UA7805C - 5.0V (ok!)
> 
> Q? AN7905F - 7.1V (um...)

Uhm. Are we talking about the ESQ1? The standard ESQ1 PSU has

- Q1: 7912 
- Q2: 7812 
- Q3: 7805 
- Q4/Q5 are transistors (MJE172/182) enabling the display blanking voltage

The digital part only uses the 5V output, so if that's up and running, 
the synth should at least react to user input, as the +/-12V are only 
used for the analog part and get (on the main board) transformed into 
-5V and +7V using two Zeners and another MJE172/182 pair (later: a 7905, 
a 7,5V Zener diode and a MJE182).
 
> Doing a system reset by holding down soft button #1 when powering on 
> made the screen flicker briefly (I think it may do that anyway when 
> you boot it up), but it just gives me the low battery warning, and 
> same old name/make/os screen.

A factory reset requires holding down REC and pressing soft button #1 
and is part of the post-reset routine, there's no way of forcing a 
factory reset during reset.

Removing the battery will force a factory reset automatically, as the 
"magic cookie" preventing the full (i.e. factory) reset cannot be found 
anymore in RAM due to the lack of battery back-up. 

Hence I was asking whether it boots w/o the battery...

Rainer