Regulators in White's

[Esteban]

Hi

Wich replacement can be good for MC341 (this is next to a LM2936 Z5 regulator)? Wich is his function?

[Carl-NC]

What model?

[Esteban]

What model?

Spectrum.

[ivconic]

What Spectrum??? I don't recall that i saw any similar in my Spectrum?? My Spectrum is first one, fat one.

[Carl-NC]

It's an MC34164 undervoltage sensor.

[ivconic]

"..MC341.." ???!!!



Esteban is eating letters!

[Esteban]

"..MC341.." ???!!!



Esteban is eating letters!

Because owner has dissambled and phone me. He said me that the LM2936 Z5.0 IS "hot", some thing is in shortcircuit. I go to his home (near my house) and removed the PCB. The coil is marked Spectrum, but no the model.

[Esteban]

It's an MC34164 undervoltage sensor.

Hi Carl, thanks very much. I anotate the model of detector (I removed the PCB). The model is J.V.N. Special Edition VXR 3.031, in PCB year 98. The coil is marked Spectrum.

Yes, the sensor is MC34164 P-5. The 5 V regulator was retired and checked and is OK, but hot when is you put in on the detector. Has some audio, but display doesn't work also.

[ivconic]

Looks like XLT... some early series..

[Esteban]

Looks like XLT... some early series..

Thanks. Maybe, box is black.

[Carl-NC]

XLT, yes. Sounds like something downstream is shorted, could be anything.

[ivconic]

Funny thing i noticed at XLT. It is more modern than Spectrum. It has more advanced uPc. PCB is smaller. Components less than at Spectrum. Overall looks like step forward. Yet it is slower than Spectrum? Slower software response, slower LCD response? Performances are identical at both models. Just Spectrum is much more faster?
Looks like Spectrum manufacturing is more expensive, so people from White's tried to make it more compact and cheaper. Lightweight, smaller battery compartment, lower drain...
Maybe a bit better S/N ratio. Spectrum uses voltage conversion, 4.8v to 13v (78S40) DC-DC. XLT uses directly 12v with no conversion. Presumably lower noise...although i haven't noticed any noise issues at Spectrum so far...
If you ask me; Spectrum is "de luxe" and XLT is "volkswagen" ! Despite the fact that Spectrum is older model.
XLT has more menu options and a bit better LCD quality. In essence those two are the very same machine with much different schematics.

[ivconic]

Back to problem;
only possible way to kill XLT is to mess up with battery. So i would recon that owner most probably wanted to use some alien battery instead original and mixed up polarities.
Esteban, if you don't have better idea than use this as starting point...
Regards!

P.S.
First of all disconnect LCD backlight driver, than continue to search for a problem.

[Esteban]

Back to problem;
only possible way to kill XLT is to mess up with battery. So i would recon that owner most probably wanted to use some alien battery instead original and mixed up polarities.
Esteban, if you don't have better idea than use this as starting point...
Regards!

P.S.
First of all disconnect LCD backlight driver, than continue to search for a problem.

Ivconic, thanks very much. This detector haven't diode for prevent invertion of polarity?

Regards

Esteban

[ivconic]

Not sure for XLT, but Spectrum don't. Spectrum has thin printed fuse (trace). Diode option would be good. However... XLT most probably don't have it also. It was not supposed to be possible to reverse battery poles at original battery, that's why it don't need diode at all.
But....it is possible to reverse poles and kill it with alien battery...