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Analogue Systems RS110 dead, pointers?
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author Analogue Systems RS110 dead, pointers?
A client managed to plug his Asys RS110 in 'upside down' and now it's pretty dead. I don't normally do repairs like this so hoping for a few pointers. Or a schematic?

On the main board there are these ICs:

3 x TL072s
1 x CA3046
1x CA3080


2 x 10uF polarised (tantalum bead) caps
2V7 zener

On the output board:

2 x TL072s

I have a ton of TL072s so swapping those out is easy enough. The zener physically doesn't look good but apart from that there are no physical signs of damage.

Obviously the two transistors and the two polarised caps are going to be suspect - any tips on testing those in situ?

The CA3046 and 3080 - I'd rather try to rule other stuff out first (seeing as I won't need to order anything) but is it likely that these are going to be dead. If so I'll just order them immediately which might save some fruitless debugging.
Without a schematic or board layout diagram it is going to be hard to debug. Is there any sign of life at all at the moment? In my experience a reverse voltage will kill most ICs and polar caps with pretty high probability.

Assuming it is totally dead then I think you have taken the right approach - start by replacing the things that are easy and then progress to replacing the things that are harder.

Generally testing caps and transistors in situ is pretty much impossible so I am afraid lots of careful work with with the hot air gun awaits!
Thank Iain.

So far I've replaced the TL072s and the zener to no effect.

The filter is just silent apart from the odd pop. It passes signal through the Notch and HP outputs (as I've just found out!) but otherwise, BP, LP and Res outputs are silent (apart from the odd pop).

Oh and the transistor array (CA3046) gets a little warm. I think it's time to start ordering ICs.... hihi
It's an old thread but, maybe @neilbaldwin can help me?

I've the same problem. I've connected the module in the wrong way.
Silence from the outputs apart some "pop"

I've to replace all the ICs?
I would go that way
- replaces obviously burned/destroyed parts
- remove all ICs, check if there is power where you expect it
- fit in new ICs
Definitely swap out those tantalum caps. They may not have burned enough to be visibly damaged, but they're destroyed very quickly by reverse polarity.

I once plugged in an Analogue Systems module backwards, and swapping the tantalum caps got it most of the way back to functioning – enough so that I could find the other problem sources.
I've replaced all the ICs, and 2 Tantalum Caps.
Now the signal pass at very low volume only from the Band Pass Out.
From the other Outs ever the same "pop" and then silence.

I'm waiting the 2 transistor BC184L and BC212L and then will see...

After that i'll try to replace all the remaining tantalum caps like @bartimaeus said
I fixed an Asys filter for someone a few years ago. I don't remember the model, but I do remember that I had to replace the transistors before it worked.
Hello Neil,

Here are some thoughts.

Destroyed parts can be evidence a problem 'upstream' - which is why the schematic is so helpful. If you have found damaged components, then replacing them *may* simply subject them to the same damaging voltage (or whatever).

In my humble experience, be careful of your confidence in saying 'I replaced those ICs, now they are good'... because they may be compromised.

I would start with the power circuitry. Perhaps the passive parts near the power cable plug? Diodes and power transistors in particular. If anything is heating up too much that is usually a darned good warning of too much power. quickly and lightly touching the IC's with clean fingers can let you know if there is a 'hot' chip. PS: They cool down very quickly. So this is done when the module is under power (no patching necessary)

Using a multimeter is kinda mandatory to see what the circuit is doing.

After reading the datasheet on chips, such as the output op amps you mention (TL072) - you can then meter voltages at the different pins and potentially see if the input signal is too much (which would only indicate the issue is further up the signal chain).

Here is the data sheet for the Texas Instruments TL072 :

I have only been doing this for a short time (4 years) and there is a lot to figure out. Please keep us updated on your discoveries and photos are a great if we can assist you further.


Also watch this, it discusses Analogue Systems power and connections.
BC184L and BC212L replaced but nothing happened...

i start to order the 2V7 zener and the remaining tantalum caps....

anyone know what kind of condenser is that?


Maybe here is the problem?....strange...the continuity test with the multimeter it's positive....
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