Ampeg A-6 Chorus Problem

[yescaster]

I have an ampeg a-6 chorus in mint cosmetic condition.

A very unabused pedal.

The effect does not come on when switched (led on).

Nothing looks cooked inside. It's very clean. the switch is a delicate looking mechanism, but it does turn on and off ok.

I tried it with power and batt.

same experience both ways.

Any info- advice- similar experiences?

- know what it is right away???


also there are two outputs on this one... a 'direct out' and 'out'. (seems there were more than one version- so a heads up- this one has a direct out also)

[yescaster]

It appears i have one of the rarer compact 80's effects on the planet.
There may have been an overseas version of this same effect, called ROzZ.

The switch-
is a pcb tact type, with a long spring (slid over a square style switch top) going to a tab on the underside of the footswitch. (the pcb tact makes a clicking sound when switched. not ambiently silent- but called a noiseless solid state switch.) Is this the same switch I wonder in any other 80's 'soft switch' boxes (can't recall any clicking)?

approx 9/16" sq x 1/4" tall. and has four prongs visible topside... but appears to have two offset tabs on either end beneath-(I have not unsoldered it), and there are "pinning tabs (one small one larger) that seat into the pcb.

is this a spst? without unsoldering it- wondering what the 2 offset solders are...no traces from either., and cant see them from topside of the switch installed.

[yescaster]

[yescaster]

[proff]

Please make a photo of wires behind the pcb. I need to see where are they connected (connection between pots, led, ps, in/out... and pcb)

[cjlectronics]

First, you are lucky cause the silk screen on the board is very detailed and it tells you what the parts are... makes it a little easlier to troubleshoot.

Second, if you've got a multimeter, check the voltages on pins 8 and 4 of the 4558 op amp. Should be around 9v with a fresh battery.

3. I'm not sure, but the transistor looking device just above the MN3101 looks like a 5v regulator????? I can't make out what the number is on the silk screen. If it is a 5v regulator measure one of its pins for around 9v and then one of the other pins for 5v. (the center pin will be ground)

4. I've seen 2SK30's go bad... as a matter of fact, quite a few of them... Suspect these as a potential problem. BTW, 2SK30's are typically used as the switch between Bypass and effect on.

Let us know your results!!

[proff]

My question was totally different of your answer... I just need to know where are pots terminal and direct out connected on pcb (rate, tone and depth)
There is not a 5V regulator in this pedal !!!

[proff]

My question was totally different of your answer... I just need to know where are pots terminal and direct out connected on pcb (rate, tone and depth)
There is not a 5V regulator in this pedal !!!

So I need to know connection between pots and other points on pcb

[waspclothes]

Any updates to this? I have an ampeg chorus with the exact same problem (light works, but no effect). Just wondering if you found a fix?

[proff]

Any updates to this? I have an ampeg chorus with the exact same problem (light works, but no effect). Just wondering if you found a fix?

I fix it and sold it Pls open it, make some pictures and send them to me in pm