I plugged in a 12v AC adaptor and I think it was designed for DC. It started
burning, etc. etc. and no longer works. What did I do exactly?

On Thu, 02 Sep 2004 06:59:28 GMT, "Asterix"
wrote:

I plugged in a 12v AC adaptor and I think it was designed for DC. It started
burning, etc. etc. and no longer works. What did I do exactly?

You broke it.

If you're lucky, you just fried a few components in the power input
section. What's a Chu Moy? Is it expensive enough to be worth
taking to a repair shop? If not, bin it and be more careful about
using the correct power supply in future :-)

"Laurence Payne" wrote in
message
On Thu, 02 Sep 2004 06:59:28 GMT, "Asterix"
wrote:

I plugged in a 12v AC adaptor and I think it was designed for DC. It
started burning, etc. etc. and no longer works. What did I do
exactly?

You broke it.

If you're lucky, you just fried a few components in the power input
section. What's a Chu Moy?

http://www.headwize.com/projects/sho...=cmoy2_prj.htm

Is it expensive enough to be worth
taking to a repair shop?

Many are self-built it seems.

If not, bin it and be more careful about
using the correct power supply in future :-)

A few cheap diodes would make it more goof-proof.

I plugged in a 12v AC adaptor and I think it was designed for DC.

You're right. It's designed for DC - specifically, DC with some
amount of regulation. It can probably work with a filtered-but-
not-regulated DC supply, but there may be some amount of hum on the
signal as a result.

It
started burning, etc. etc. and no longer works. What did I do
exactly?

If this was built according to the circuitry at www.headwize.com,
it appears that there's no reverse polarity protection. AC would
definitely be bad for it.

Feeding AC into it would have put a high amount of ripple current
through the filter capacitors (C1 and C2) and would have
reverse-polarized them during half of each cycle. This might have
caused a catastrophic failure (swelling, leaking, venting of the cap
cans themselves) or, at least, have changed their electrical
characteristics. Feeding in AC would also have caused reverse voltage
to be fed to the power supply pins of the OP134A op amps, and I
suspect that this would likely have destroyed them.

I think you'll certainly need two new op amps. It'd probably be a
good idea to replace C1 and C2 as well. Adding anti-polarity-reversal
diodes to the power supply input would be an excellent ideas, as well.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

A few cheap diodes would make it more goof-proof.

Did I tell you about my Sony Walkman Professional? This expensive
unit can't tolerate reversed polarity on the 6v input. As you say -
a few pennies spent on a diode....

Laurence Payne wrote:

A few cheap diodes would make it more goof-proof.

Did I tell you about my Sony Walkman Professional? This expensive
unit can't tolerate reversed polarity on the 6v input. As you say -
a few pennies spent on a diode....

But then they would have to up the volts / watts / price on the ac
adaptor !


Graham

Yes, I think it was built according to those plans, it is a popular design
and a few people are selling them on e-bay. I got mine for about $60 and had
to fight to get it, about 15 people bid. Anyway, I'm recieved a response
from the guy via e-mail, I don't know what he can do now that it's destroyed
but we'll see...



"Dave Platt" wrote in message
...
I plugged in a 12v AC adaptor and I think it was designed for DC.

You're right. It's designed for DC - specifically, DC with some
amount of regulation. It can probably work with a filtered-but-
not-regulated DC supply, but there may be some amount of hum on the
signal as a result.

It
started burning, etc. etc. and no longer works. What did I do
exactly?

If this was built according to the circuitry at www.headwize.com,
it appears that there's no reverse polarity protection. AC would
definitely be bad for it.

Feeding AC into it would have put a high amount of ripple current
through the filter capacitors (C1 and C2) and would have
reverse-polarized them during half of each cycle. This might have
caused a catastrophic failure (swelling, leaking, venting of the cap
cans themselves) or, at least, have changed their electrical
characteristics. Feeding in AC would also have caused reverse voltage
to be fed to the power supply pins of the OP134A op amps, and I
suspect that this would likely have destroyed them.

I think you'll certainly need two new op amps. It'd probably be a
good idea to replace C1 and C2 as well. Adding anti-polarity-reversal
diodes to the power supply input would be an excellent ideas, as well.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Did I tell you about my Sony Walkman Professional? This expensive
unit can't tolerate reversed polarity on the 6v input. As you say -
a few pennies spent on a diode....

But then they would have to up the volts / watts / price on the ac
adaptor !


Graham


Not if you put a single (reversed) diode from input to ground. I've seen
this often and the diode usually burns short. Better a blown PSU.

Gareth.

In article r4RZc.3282$A63.1670@trnddc09, "Asterix" wrote:
Yes, I think it was built according to those plans, it is a popular design
and a few people are selling them on e-bay. I got mine for about $60 and had
to fight to get it, about 15 people bid. Anyway, I'm recieved a response
from the guy via e-mail, I don't know what he can do now that it's destroyed
but we'll see...

I think just replace the op-amp, especially if its mounted in a socket??

greg


"Dave Platt" wrote in message
...
I plugged in a 12v AC adaptor and I think it was designed for DC.

You're right. It's designed for DC - specifically, DC with some
amount of regulation. It can probably work with a filtered-but-
not-regulated DC supply, but there may be some amount of hum on the
signal as a result.

It
started burning, etc. etc. and no longer works. What did I do
exactly?

If this was built according to the circuitry at www.headwize.com,
it appears that there's no reverse polarity protection. AC would
definitely be bad for it.

Feeding AC into it would have put a high amount of ripple current
through the filter capacitors (C1 and C2) and would have
reverse-polarized them during half of each cycle. This might have
caused a catastrophic failure (swelling, leaking, venting of the cap
cans themselves) or, at least, have changed their electrical
characteristics. Feeding in AC would also have caused reverse voltage
to be fed to the power supply pins of the OP134A op amps, and I
suspect that this would likely have destroyed them.

I think you'll certainly need two new op amps. It'd probably be a
good idea to replace C1 and C2 as well. Adding anti-polarity-reversal
diodes to the power supply input would be an excellent ideas, as well.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!