Sony Vrd Mc6 Dvdirect Dvd Burner Recorder

To make a start, power it up and check for voltages around the board.............. like around the input socket to see if anything is coming through. Any decent board should have reverse pol protection. Check for that.

On Wed, 6 Feb 2013 19:26:20 +0000, juanvivo put finger to keyboard and composed:

AFAICT, T3 is a dual inductor that filters each side of the DC supply. As long as there is continuity between points A and B, and between C and D, then the component will not need to be replaced.

I would test for a short circuit between B and D. If there is no short, then check the voltage test points on "placa2grande", specifically TP12V, TP5V, TP1V8, and TP3V3.

- Franc Zabkar

Hello Phoull Rheilly , thank you very much for your answer.

I have 12 volts only at the point that I've marked with A. Anywhere over the plate. I think this is not a decent plate, why not see protection.

Thanks for your help Franc Zabkar,

No continuity between A and B. Continuity between C and D. There is also continuity between B and C-D.

Currently if I connect power to the board, there is no voltage on any of the test points I've tried.

Thank you very much for your help.

Excuse my poor English ...

Hi juanvivo.. it was me that posted the problems with an MC5 model.

In your placa2 pic, there is a diode near the 12 volt power input connector, marked D7. It may be worthwhile to test the diode for shorted condition.. diode test with a DMM, or ohms with an analog meter.

Since you mentioned that the T3 has no continuity from A to B, that indicates that the transformer/inductor is (likely burned) open. The inductor will need to be replaced, but could be jumpered from A to B for testing purposes. Placing a jumper across T3 terminals A to B will restore continuity for the positive (+) side of the external power supply.

If you use a low amperage fuse in the external power supply lead, you should be able to proceed with testing/checking for voltages on the circuit board. I would expect that connection of all of the cables and the LCD display would be required to proceed.

The Sony power supply for these models is a regulated 12V supply, so an unregulated power supply (transformer/rectifiers) wouldn't be the best choice for this unit. A high capacity 12V battery or power supply may cause more damage if the power leads don't include a low current fuse.

In the future, for trying equipment using external power supplies, it's a good practice to always have a fuse in the power lead. I was surprised that the MC5 model had no internal fuse devices, as Franc made clear to me.

Also for future testing purposes, if you're not sure which connector contact is for the negative (-) of the external power supply, many times it will be the contact which shows direct connection to the unit's connectors such as the shell/shield of RCA jacks (inputs or outputs) intended to be connected to other equipment.

These circuit boards are fairly complex and without a service manual, all I was able to do was hunt for defective (simple) components.

Don't forget that there is a short form B-C.

The author didn't specify a short between the 2 power input sides.. what he stated was continuity (and his native language isn't english).. it's also not exactly clear what type of equipment he's using for testing.

Diode D7 is physically close to the power connector, and its designation 7 suggests that it's electrically near the connector. If the diode is shorted across the DC supply, one of the conductors in T3 would open if unable to handle the current.

D7 may not be across the DC supply, and not have anything to do with the T3 failure.. that's up to the person testing the unit to determine.

Thank you so much for your help and for your time. I would be lost without your help.

Wild_Bill;3010198 Wrote:

When I use my multimeter and put pointers in A and B, not continuous beep sounds. When I put them in C and D, if continuous beep. Between C and B are also continuous beep. If I measure ohms, I get no reading. points are shorted. Not if I explain well, again excuse my poor English, my language is Spanish.

I've checked the diode D7 with diode tester position and seems to be fine. NO appears damaged.

I think for a first test, should desolder T3 to see if the short is removed. no?

Once this is done, if the short is gone, then put jumpers between a and b, and between b and c and check readings. Is that correct?

I have to do the tests with the lcd and dvd connected or I can make them without them connected?

When I reverse polarity i use a car battery.

in the future I assure you I will use diodes. I assure you I have learned the lesson.

If I can not express myself well, or some of the things I say does not make sense, tell me. Consequence management is that little English.

Well, he did say "No continuity between A and B. Continuity between C and D. There is also continuity between B and C-D.".

But you are correct. We do not know what "continuity" means. B to C could just be the load.

Regards, tm

En el artículo , Rheilly Phoull escribió:

I can't spot any on that board.

En el artículo , juanvivo escribió:

Whoops. No wonder T3 is a goner.

Your English is fine :)

On Thu, 7 Feb 2013 14:28:54 -0500, "Wild_Bill" put finger to keyboard and composed:

I'm guessing that D7 is a Schottky diode. I suspect that D7, L4 (6.8uH) and U16 form a buck regulator that generates the +5V supply. I can't see any reverse polarity protection on the PCB, so I would think that U16 would have been hit.

The L2 and L3 coils are probably associated with U17 and U14 to form their own +1.8V and +3.3V buck regulators. I suspect that each of these ICs would have been hit also.

If I were the OP, I would locate the datasheets for the three ICs and examine their application circuits, if any.

- Franc Zabkar

On Thu, 7 Feb 2013 21:01:16 +0000, juanvivo put finger to keyboard and composed:

I doubt that the two windings would be shorted to each other, but yes go ahead.

Jumper A & B, and C & D, not B & C.

Leave them disconnected.

- Franc Zabkar

On Fri, 08 Feb 2013 16:15:03 +1100, Franc Zabkar put finger to keyboard and composed:

On second thoughts, if you are testing for shorts between B and C, then you should connect the LCD and DVD one by one to confirm that neither of them are shorted also.

- Franc Zabkar

It's likely that your guesses are correct Franc.. you're far more knowledgeable about these circuits.

I suspect that there is likely to be widespread damage from connecting to a car battery with the polarity reversed.. surprising to me that there aren't any obvious burnt parts to see.

It seems that Sony hasn't provided any circuit protection at all in the VRD-MCn models, and when not using the original Sony PSU the user risks causing damage.

The MC6 version is the latest model and is typically priced at about $200, so a mistake can be costly. I didn't contact Sony to see if a service manual is available, but that would probably be the only way I could effectively troubleshoot these units.

-- Cheers, WB .............

When I say continuity, I mean they are directly connected.

Are shorted.

B, C and D are in short. Or put another way, B, C and D are connected directly to ground.

What is the correct way to say it in English?

Your meaning is clear, it would most likely be said as in line 3.

"are directly connected to ground".

I would think your English is better than many here can speak Spanish :-)

U17 : 4407 DA9S1E

U16: 54331 97M AOXR 'Converter (Integrated Switch) - Step-Down (Buck) Converter - TPS54331 - TI.com'

U14: TPS or PS 53124 TI 96K DQ4C . I´m nor sure with the "T" searching...

On Fri, 8 Feb 2013 12:29:43 +0000, juanvivo put finger to keyboard and composed:

U16 is a PWM controller with integrated MOSFET chopper:

The application circuit on page 11 of the datasheet shows an external Schottky flywheel diode. The part number (B340A) matches the markings on D7.

AFAICT, this would constitute the +5V buck converter.

It looks like U17 is a P-channel MOSFET. Normally in that position I would expect it to be functioning as an external chopper for one of the buck converters. However U16 has its own internal chopper. Is it possible that U17 provides additional current for U16?

It appears that U14 controls two buck coverters (+1.8V and +3.3V):

"The TPS53124 is a dual, Adaptive on-time DCAP mode synchronous controller."

There is a typical application diagram on the first page of the datasheet.

- Franc Zabkar

On Sat, 09 Feb 2013 08:44:00 +1100, Franc Zabkar put finger to keyboard and composed:

AF4407P, Anachip, P-Channel 30-V (D-S) MOSFET:

"Typical applications are PWM DC-DC converters, power management in portable and battery-powered products ..."

AO4407, Alpha & Omega Semiconductor, 30V 12A P-Channel MOSFET:

"This device is ideal for load switch and battery protection applications."

I wonder if U17 is a high-side power switch ???

- Franc Zabkar