Echoflanger "half working"

[DS-1]

Hi guys!

I have this original unit that works fine only on chorus/echo slap mode.

Flanger and filter matrix is not working at 100%. Both positions have no sound when all the pots are at max. In the intermediate position of the rate pot, the effect seems to have no effect anymore on sound.

What can I check on the PCB? Could anyone please help me to find any issue?

Thanks a lot for the reply!

[ElectricDruid]

Have you got a schematic for it? Some more details would help.

If it works in chorus/echo mode, then that sounds like the BBD delay chip(s?) must be working, which would be good news. So probably something is either wrong with the switching, or something that gets switched in only in that mode isn't working.

But without a schematic, we're guessing. Some photos of the pedal would be useful too, so we can see what's going on.

Thanks!

[Kevin Mitchell]

If I were in your shoes I'd inspect the CD4053 chips first. Make sure what's going in is also coming out in the questioned settings.

[StephenGiles]

Almost certainly the CD4053 is not working as it should.

[DS-1]

Thanks to everyone for the replies.

I have got no schematic for it, even if I've seen a lot of posts here in which maybe I can find something interesting.

Here some pics of the pedal:










The first thing that come to my eyes is that the IC named SCL4013A is a 7 pin IC in a 8 pin socket. Also, I've seen several Echoflanger PCB and I see that they all have 8 pin IC on that socket.

[Kevin Mitchell]

The 4013 is 14 pin dual in-line package. It's not uncommon for larger sockets to be used in old instruments. 16 pin sockets were way more prevalent than 14 pin sockets back then. If you look closely, you'll see that two of the socket pins were pulled so that it would seat through the 14-pin footprint.

There is a schematic around, but it's quite messy.

A couple of us had pointed to the 4053 chips being a likely cause of the issue on first impression. They are 3 single-pole double throw analog switches in one package. Each channel is actuated with logic signals at V+ level. Reviewing the pin-out diagram will help you understand and follow along.

You'll want a multimeter as well as an audio probe or oscilloscope.
Do you have these?

Be careful with those BBDs. You're SOL if you damage either of those SAD1024s.

[DS-1]

The 4013 is 14 pin dual in-line package. It's not uncommon for larger sockets to be used in old instruments. 16 pin sockets were way more prevalent than 14 pin sockets back then. If you look closely, you'll see that two of the socket pins were pulled so that it would seat through the 14-pin footprint.

There is a schematic around, but it's quite messy.

A couple of us had pointed to the 4053 chips being a likely cause of the issue on first impression. They are 3 single-pole double throw analog switches in one package. Each channel is actuated with logic signals at V+ level. Reviewing the pin-out diagram will help you understand and follow along.

You'll want a multimeter as well as an audio probe or oscilloscope.
Do you have these?

Be careful with those BBDs. You're SOL if you damage either of those SAD1024s.

I have a multimeter and an oscilloscope too (my father used it), but I'm able to use multimeter only.

I have a couple of Texas Instrument CD4023BE that I should try to see if them works fine.

[Kevin Mitchell]

I have a couple of Texas Instrument CD4023BE that I should try to see if them works fine.

Please don't.

[DS-1]

Ok, but why shouldn't try these on the Echoflanger? Just to know.

[Phend]

That switch in the middle looks grimy. Contact cleaner ?
Switch it back and forth fast a few dozen times ?

[Kevin Mitchell]

Ok, but why shouldn't try these on the Echoflanger? Just to know.

Because a CD4023 NAND gate IC is not a CD4053 analog switch IC. If you plug one in and nothing happens, that's your best case scenario. Otherwise you'll be creating even more problems by dropping in a random chip that doesn't belong to the circuit.

I'll try to make it simple for you to test the 4053 chips.
As I've said, you want to make sure what's going in is also coming out. But you can't do that adequately without a scope or audio probe - preferably a scope as I believe these switches are used in both the audio path as well as the clock circuit. But we make-do where we can (hence, audio probe)

These chips have 3 channels. Channel X, Y and Z.
There are two pins (in/out) per each channel.
There is also a control pin for actuating these switches - one for each channel. Logic high is to one position, logic low is to another.

Just to get you going, with your multimeter in DC mode inspect each control pin, pins 9, 10 and 11. Now you'll know what they are at rest, on or off. Now use the rotary switch and watch for changes on any of these pins in each rotary position. Ensure that the channel is indeed in use - as some might be held to a supply rail as an unused channel. Do this by looking at the traces under the IC. If you see a single copper trace going through multiple pins (more than a couple), it implies a disabled channel. Usually unused pins are tied to the ground signal.

These suggestions apply to both/all 4053 chips.

Write down your findings per each rotary throw to review your notes. Share your notes with us - including what pins you're measuring as well as what throw the rotary switch is in (1st position, 2nd and so on). While this will not show if the CD4053 chips are the problem, we can at least know if the control signals are doing their thing and we may proceed with more in-depth advice. Again, you're going to wish you had a scope or audio probe moving forward.

Vintage should stay vintage. Please don't replace anything unless you're confident that it needs replacing. This will make a better learning experience for you and also retain some value of the vintage pedal. I mean, it's yours do what you want, but please do so wisely.

[DS-1]

Ok, but why shouldn't try these on the Echoflanger? Just to know.

Because a CD4023 NAND gate IC is not a CD4053 analog switch IC. If you plug one in and nothing happens, that's your best case scenario. Otherwise you'll be creating even more problems by dropping in a random chip that doesn't belong to the circuit.

I'll try to make it simple for you to test the 4053 chips.
As I've said, you want to make sure what's going in is also coming out. But you can't do that adequately without a scope or audio probe - preferably a scope as I believe these switches are used in both the audio path as well as the clock circuit. But we make-do where we can (hence, audio probe)

These chips have 3 channels. Channel X, Y and Z.
There are two pins (in/out) per each channel.
There is also a control pin for actuating these switches - one for each channel. Logic high is to one position, logic low is to another.

Just to get you going, with your multimeter in DC mode inspect each control pin, pins 9, 10 and 11. Now you'll know what they are at rest, on or off. Now use the rotary switch and watch for changes on any of these pins in each rotary position. Ensure that the channel is indeed in use - as some might be held to a supply rail as an unused channel. Do this by looking at the traces under the IC. If you see a single copper trace going through multiple pins (more than a couple), it implies a disabled channel. Usually unused pins are tied to the ground signal.

These suggestions apply to both/all 4053 chips.

Write down your findings per each rotary throw to review your notes. Share your notes with us - including what pins you're measuring as well as what throw the rotary switch is in (1st position, 2nd and so on). While this will not show if the CD4053 chips are the problem, we can at least know if the control signals are doing their thing and we may proceed with more in-depth advice. Again, you're going to wish you had a scope or audio probe moving forward.

Vintage should stay vintage. Please don't replace anything unless you're confident that it needs replacing. This will make a better learning experience for you and also retain some value of the vintage pedal. I mean, it's yours do what you want, but please do so wisely.

Sorry, i just wrote it wrong.

It's a couple of CD4053BE, not CD4023. It's from Texas Instrument.

[Kevin Mitchell]

Sorry, i just wrote it wrong.

It's a couple of CD4053BE, not CD4023. It's from Texas Instrument.

Go for it then - they are drop-in equivalent. If they don't work, I suggest putting the old ones back and following my advice on monitoring their control pins.

This CD4053 diagram will help too - easier to follow than the datsheet info.


For the record, here's the schematics.
Page 1
Page 2

[Phend]

Cold shorts, happen in aged electronic devices.
Check the one next to the black wire.
And others I see as candidates.
(BTW Hot pants do not happen in the aged, lol !)
(You need to have been there)

[DS-1]

Hi to everyone!

This morning I had a couple of hours to install the two new ICs on the Echoflanger pcb. Now it works fine! I can't say if the filter matrix and the flange positions sound at their best (I have a 99 Polychorus that sounds a lot different, so I can't compare it), but now these two positions sound with every knobs position and the two positions effect sound a lot more present than before.

Now I believe I would like to check which one of the two 4053 doesn't work...Could I try with one new and one old?

Also: which one of the two affects the filter matrix and flange sound?

Thanks a lot to everyone for the tips!

[Kevin Mitchell]

This morning I had a couple of hours to install the two new ICs on the Echoflanger pcb. Now it works fine! I can't say if the filter matrix and the flange positions sound at their best (I have a 99 Polychorus that sounds a lot different, so I can't compare it), but now these two positions sound with every knobs position and the two positions effect sound a lot more present than before.

Progress is always great news!

Now I believe I would like to check which one of the two 4053 doesn't work...Could I try with one new and one old?
Also: which one of the two affects the filter matrix and flange sound?

Of course you can.

Both of these switch ICs affect all settings. I know it's a pain, but if you sift through and follow the schematic you'll see that when the rotary switch is set to either filter matrix or flange half of the switch (one pole) actuates 3 switch channels, IC7 (channel Z) in the clock, IC6 (channel X) in the signal path and IC6 (channel Z) in the signal path.

When you change the mode switch it actuates the switch ICs in both the clock circuit and the audio circuit. So the question should be, which side of the design is giving you trouble?

Edit, perhaps finding which 4053 is bad and swapping it's location will make this obvious to you. But you'll want to find out what channel of which IC is bad.

Build yourself an audio probe and we'll tell you where to audibly inspect.
Does your multimeter have a frequency setting to measure hertz?

[DS-1]

This morning I had a couple of hours to install the two new ICs on the Echoflanger pcb. Now it works fine! I can't say if the filter matrix and the flange positions sound at their best (I have a 99 Polychorus that sounds a lot different, so I can't compare it), but now these two positions sound with every knobs position and the two positions effect sound a lot more present than before.

Progress is always great news!

Now I believe I would like to check which one of the two 4053 doesn't work...Could I try with one new and one old?
Also: which one of the two affects the filter matrix and flange sound?

Of course you can.

Both of these switch ICs affect all settings. I know it's a pain, but if you sift through and follow the schematic you'll see that when the rotary switch is set to either filter matrix or flange half of the switch (one pole) actuates 3 switch channels, IC7 (channel Z) in the clock, IC6 (channel X) in the signal path and IC6 (channel Z) in the signal path.

When you change the mode switch it actuates the switch ICs in both the clock circuit and the audio circuit. So the question should be, which side of the design is giving you trouble?

Edit, perhaps finding which 4053 is bad and swapping it's location will make this obvious to you. But you'll want to find out what channel of which IC is bad.

Build yourself an audio probe and we'll tell you where to audibly inspect.
Does your multimeter have a frequency setting to measure hertz?

I have to check if my Fluke has a frequency setting for hertz. I'll update as soon as possible.

Also, this unit has the main foot switch with 3 pin, with only two of them connected to pcb. Should the third one be connected?

[DS-1]

Hi guys!

Unfortunately I was too busy with work and with rehearsals that I had no time to check the things we talked about, but I've discovered another thing about this Echoflanger: when using the chorus and slap back modes, If I have the tune knob set to 0 and the blend switch to OFF, I have a delay in sound. The more I move the tune knob, the more the delay disappear.

In the newer Polychorus I have (around 2000), this doesn't happen. Is this normal for the Echoflanger, or there's something not working properly?