Is this IRS21xxx?

[nonprof]

Hello!

Please somebody give the name of this driver 14pins IC? I know this is IRS21xxx? Pin 2 is the shutdown pin.
Please see attached file...

In our country this harvested from QAMP 1500.1

Thanks you!

 

[Perry Babin]

I was fairly sure that this was the 21844 but not 100% so I dropped one in a lightning amp that uses the same board and it works. I used the IRS version.

 

[nonprof]

I was fairly sure that this was the 21844 but not 100% so I dropped one in a lightning amp that uses the same board and it works. I used the IRS version.

Thanks Perry to your usual support to us!

 

[nonprof]

DC out fault

Hello everyone!

I have a couple questions, Is that the PT-IN pin in the driver board is where the DC-out protect signal coming in? Pls see attached PT-in sch.
And in 2nd schematic, somebody pointed me which circuit is responsible for monitoring DC-out?
Pls. see attached DC-out schematics.


1. This amp has a DC out and does NOT protect. Audio signal pin at the driver board is masked by the - rail voltage , the Audio-in signal was clamped at -5.6V, oscillation dies and sent straight DC to IRS21844, cause turning on the low side output fet. DC out protect circuit not worked this time.

2. Cycling the power, sometimes DC out gone but the IRS21844 is in shutdown mode. A good audio signal coming in to IRS21844, output fets are turned off.

Measurements at driver board pins:
PT-in = -78.4V
SD-R(with DC out) = -70, (without DC out) =-76V
-VCC= -78.7
-VCC+12V= -66.8V
MOL=-78.4


I guess, I'm having problem in DC out protect circuit or turn-on delay?

Thanks,

 

[nonprof]

I just notice in IRS21844 driver that my SH pin measures approx. 1.1Volts without DC out and protection and seems it sync with the input signal.

May I know what is the shutdown max voltage?
I remove all the connection(diode and NPN transistor) of the SH pin, but it still measure 1.1volts, I expect a close to 5volts because of internal pull up.

I may order again a new driver IC.

Thanks!

 

[Perry Babin]

With a pot connected as shown (wiper on pin 2), The IC drops out at about 1.6v when transitioning from high to low. It begins to oscillate at about 2.1v when transitioning from low to high.

 

[nonprof]

thanks perry!

 

[nonprof]

thanks perry!

Hi Perry, I followed this procedure. Driver doesn't turn on all around. The input pin voltage followed the SH voltage🙂 They might have internal leakage so I will order new one.

Thank you so much!

 

[Perry Babin]

If you're ordering from a source that doesn't pack the ICs with desiccant and a humidity card, buy from a different source. Also be careful not to apply too much heat or apply the heat for too long. These ICs are very sensitive.

 

[nonprof]

ohh my God...one customer pulled out his amplifier after it takes a month to repair his amp, that's frustrating it's my 1st time that I did not repair an amp.
I replaced 3 drivers but always failed. I applied 40watts soldering iron and careless when installing this driver.

Now it happened again...thank you so much Perry!!!

 

[nonprof]

Hello Perry,

Do you have schematics of this driver board and/or this amp? After I replaced the driver the amp still has DC out = -rail.

Which part of the amp circuit monitors the DC out?

Thank you!

 

[Perry Babin]

The DC is controlled by the op-amp on the driver board. Look at the DC voltage on the inputs and the output of the op-amp to see if the output is in agreement with the input.

I don't have a diagram for this board.

 

[wolfi084]

Hello everyone!

I have a couple questions, Is that the PT-IN pin in the driver board is where the DC-out protect signal coming in? Pls see attached PT-in sch.
And in 2nd schematic, somebody pointed me which circuit is responsible for monitoring DC-out?
Pls. see attached DC-out schematics.


1. This amp has a DC out and does NOT protect. Audio signal pin at the driver board is masked by the - rail voltage , the Audio-in signal was clamped at -5.6V, oscillation dies and sent straight DC to IRS21844, cause turning on the low side output fet. DC out protect circuit not worked this time.

2. Cycling the power, sometimes DC out gone but the IRS21844 is in shutdown mode. A good audio signal coming in to IRS21844, output fets are turned off.

Measurements at driver board pins:
PT-in = -78.4V
SD-R(with DC out) = -70, (without DC out) =-76V
-VCC= -78.7
-VCC+12V= -66.8V
MOL=-78.4


I guess, I'm having problem in DC out protect circuit or turn-on delay?

Thanks,

Hello!
Can you sent to the complete the schematic drawing.
I would really appreciate!