Maestro Echoplex ep3 sound on sound static

[DaveST]

Hi all,

I'm getting ready to sell my ep3 maestro echoplex. It echoes perfectly. However, when I flip the switch down to sound on sound, all I hear is loud static. Any ideas on how to repair this? You advice is greatly appreciated. Thank you.

Dave S

[oc disorder]

Hi DaveST

Just to get you started , there are a few versions of the ep3.
The version is determined by the serial number.
The "ECHOPLEX_OWNER-SERVICE_MANUAL.pdf" (approx 23 megs)
is here :-

http://www.synfo.nl/servicemanuals/M...ICE_MANUAL.pdf

Regis , a member of this forum, has hands on experience with one and has
provided a helpful page here on his web site :-

Regis's Echoplex Page

After having a quick look at the manual it appears the circuitry or electronics is shared
by both the echo and sound on sound selection which to me narrows it down
to the head being open circuit or a double pole changeover switch which
is a bit easier to fix !

You will need a multimeter set to resistance with the machine off !!! to check these.



The switch is a double pole change over switch the two center connections either connect
to one set of contacts at the top or when thrown the other set of contacts on the bottom.
From my diagram/picture 1 is connected to 2 or when switch thrown connected to 3.
Likewise the not visible set of contacts 4 connects to 5 or ...6.
Its two "or's" in one !


So you should get a zero ohms reading (continuity beep will also indicate if the contacts are connecting) across
1 and 2 and 4 and 5 and when you flick the switch 0 ohms or beep between 1 and 3 and 4 and 6.

According to the manual (possibly dependent on model) if you follow the black and white wires from the sound on sound head
(on the right?) they terminate on the switch so in the sound on sound position you should get a resistance reading
of approx 400 ohms between those two (B&W) wires on the switch.

In the echo position those wires should be shorted or measure zero ohms.. ie connected together !

Hope that's some use

Posting back here with the model number and the results of this initial test should help anyone on the forum
to assist.

Make sure it's unplugged from power or we may never know what happened !

[52 Bill]

We've been discussing this one over in the guitar FX forum. He knows that it's not the switch so it's either the sos head or the wiring.

[DaveST]

Wow, the response had been very helpful. I want to thank you all for trying to help. The problem is i'm not an electrician and I don't know how to work on these typed of things. I guess I was hoping it was some kind of easy quick fix. I wanted to sell this machine in perfect condition. Whatever happened to it, happened during the long term storage of it, because it was working perfectly the last time I played with it many years ago. I believe I'll just have to sell it as is unless I find someone in the Tampa area who knows how to work on these things. incidentally, the serial number is 35006. Everything else on it works and looks great! once again, thank you.

[oc disorder]

We've been discussing this one over in the guitar FX forum. He knows that it's not the switch so it's either the sos head or the wiring.

Thanks for that Bill.. going blind down here in the cold !
Well at least both threads conclude with measurement data required....

I'm still a heathen re the switch 'till he pokes it with a stick um meter probe..

An mp3 may dissuade me when I hear the clickity clack...clickity clack ... clickity clack...

[oc disorder]

Well Dave.. even a hot rod enthusiast with a multi-meter should be able to check the switch for you.
Otherwise I heard Walter Becker had some success getting a bunch of Buddhist Monks to
de- demonize his studio. Apparently all the bugs were banished.!
You could try that although we don't want to encourage It.
It would decimate the service industry !

[Enzo]

Echoplexes are everywhere. Any competent amp tech can work on them. Schematics are readily available.

[52 Bill]

I'm still a heathen re the switch 'till he pokes it with a stick um meter probe..

Amen, agree 100%.

Dave- If you don't want to test or clean the switch, try flipping it back and forth a few times and see if that will clean it enough to get it working again.