Boss RE20 Space Echo effects pedal

[N_Cook]

The DSP works giving a spacey output but only when the Intensity control
is at 3/4 to full, so too much, and straight through input sound
component very low level.
Straight through, effects off, is good normal signal level out.
The pots and switches check out ok, the mode switch is resistive and
does the mode change ok.

 

[N_Cook]

Looking closer, corrossion product from beer or whatever near the input
and SMD FET and a 4558, gives something non-dsp, to probe tomorrow, no
mention of beer-swilling of course.

 

In an SMD device codebook I have, XG is a BZX284-B13 and is listed as a 0.4W 13V zener. An XGs is an BCR523 which is an NPN DTR 50V 0.5A.

Hope this helps,
Dan

 

[N_Cook]

2 topcode XG marked FETs? on the board, both with 21.7V on and other
pins reasonable looking DC on them, one with corrossion around.
No mention of phantom power in the user manual, I wonder what that is
doing near the input. 9.3V fed onto battery supply line.
2x JRC 14558,IC4 and IC2 that one in corrossion , the other some way
away, 0,8.2V supplies and 6x 5.5V on the other pins.
The corroded one power rails and only 2, pins 3 and 5 commoned at 5.5V
and 4 pins with all sorts of DC and varying somewhat, in effects on or
off mode.
So off with that SMD and a 4558 will go in there and see what happens

 

[N_Cook]

On 09/12/2015 17:58, dansabrservices@yahoo.com wrote:

In an SMD device codebook I have, XG is a BZX284-B13 and is listed as a 0.4W 13V zener. An XGs is an BCR523 which is an NPN DTR 50V 0.5A.

Hope this helps,
Dan

Whatever the XG are, they are true 3 pin active SOT23 devices, not 2
plus common

 

[N_Cook]

On 09/12/2015 15:16, N_Cook wrote:

2 topcode XG marked FETs? on the board, both with 21.7V on and other
pins reasonable looking DC on them, one with corrossion around.
No mention of phantom power in the user manual, I wonder what that is
doing near the input. 9.3V fed onto battery supply line.
2x JRC 14558,IC4 and IC2 that one in corrossion , the other some way
away, 0,8.2V supplies and 6x 5.5V on the other pins.
The corroded one power rails and only 2, pins 3 and 5 commoned at 5.5V
and 4 pins with all sorts of DC and varying somewhat, in effects on or
off mode.
So off with that SMD and a 4558 will go in there and see what happens

Normal function returns for all that Star-Trekky stuff.
4.1V dc (half 8.2V) now on both 4558 pins ins and outs, all 12 such
pins. I'll try and find out how beer got to where it pooled , as not an
obvious landing place.