hard repair from HR-DVS1EU smps

[rickou]

im a hobbist and for 2 weeks i'm trying to repair a smps from a mini dv and vrc from 1999 collection.

The symptoms are these:
I have a standby light the device turn on, I have some functions, sometimes I can read the tapes, sometimes I can not, sometimes it eject sometimes not, etc.

So I can see until now is that I have a problem in the feedback on the secondary side which causes the ic5101 to stay with 4.8v on pin 1 and it activate the protection and the smps is always on and off I have some voltages in the connector Cn5201.

i will provide the datasheet from the smps and i have all so the service manual.
i can all so provide pics with the osciloscope if need.

[cpt.charlie]

Re: hard repair from HR-DVS1EU smps

Make sure you have no overload at the PSU output, check r5101 and c5107.

[budm]

Re: hard repair from HR-DVS1EU smps

Since it is an always on power supply even when the Power switch is not activated, you should have ALL the output Voltages from that power supply.
you also have some circuit protection devices 'CP' as shown in the diagram that you need to check.
So find out what kind of Voltage you have when the power switch is not activated.
C5103 startup/running cap in the primary side should also be checked.

[rickou]

Re: hard repair from HR-DVS1EU smps

so here are the voltages at the conector cn5201:

1=17V 10=8V
2=GND 11=8V
3=-12V 12=4,9V
4=GND 13=variable from 2V to 37V (Osciloscope10v/div 20.00uS)
5=GND 14=variable from 2V to 37V (Osciloscope10v/div 20.00uS)
6=12V 15=0V
7=GND 16=0V
8=8V 17=0V
9=-11.4V 18=0V
19=2.3V

At octocoupler pin 1=11.6V pin 2=11.6V pin 3= 2.6V pin 4=2.6V
At ic5101 everything ok i have the pwm for transformer only the pin 1= is high +- 4.7 (osciloscope Vmax10v) the OCP/FB is active from this IC.

i have check all the caps but i dont figure out and understand the feedback from the secundary side of the PSU.
really need some help

[budm]

Re: hard repair from HR-DVS1EU smps

Since there are no pin names associated with those pins then I have no ideas as to what those pins are and what Voltages we are expecting from those pins.
How about uploading the service manual?

[eccerr0r]

Re: hard repair from HR-DVS1EU smps

1=17V(17V)
10=8V(6V)
2=GND
11=8V(6V)
3=-12V(-29V)
12=4,9V
4=GND
13=variable from 2V to 37V (Osciloscope10v/div 20.00uS) (could fluctuate)
5=GND
14=variable from 2V to 37V (Osciloscope10v/div 20.00uS) (48V - This is suspect, it should not fluctuate, check C5207, D5210)
6=12V(12V - Main Feedback line)
15=0V
7=GND
16=0V
8=8V(5V)
17=0V
9=-11.4V("Audio")
18=0V
19=2.3V

Pins 15-18 are isolated and you should get no volts between these and GND, however you should get voltage from pin 17/18 to pin 15/16.

Except for the fluctuation and that capacitor above, it looks the feedback circuitry is fine.

Your -29V is a bit low, check voltages around R6306 (flame resistant 47 ohm), D5211 (aud1z), and C5208 (15? 18?uF 50V)... though the schematic is pretty illegible there...

[rickou]

Re: hard repair from HR-DVS1EU smps

here are the following mesures:

at D5211 ok the cap C5207 ok and the flame resistor all so ok.
what i found suspect is the diode D5305 (ad30es/b1) and D5303 (mtzj12c) D5306 (Rd2.7e5)/b2.
i have take them out of circuit to test wiht the atlas DCA pro75 and it sad them are normal diodes normamaly should say that is a zenner diode or not?
is it possible that the transistor Q5301 and the Q5302? because the base of q5301 i have 0V.

[Longbow]

Re: hard repair from HR-DVS1EU smps

A couple of things to look at are R5105 - .47 ohm current sense resistor. This part might have increased in value.

Power source for IC5101 is R5102, D5103, C5103. That voltage should be steady and free from h.f. ripple.

Finally, the feedback circuit monitors the 5v. and 12v. via D5311 and D5312. Both of those lines must be free of h.f. ripple (filter caps), or you will get erratic operation.

[rickou]

Re: hard repair from HR-DVS1EU smps

the anothe of D5311 i have 5v no rippel and anothe of D5312 i have 12V no rippel in the cathode of D5311 i have 12.5V (picture 1).

now the trick one i have before mesure the pin 4 of IC5101 i had 12V (multim) now i mesure with osciloscope i have see that i have 12v with ripple (pic2) i have take the cap and mesure it has fine 39uF 25V 0.02esr i replaced anyway, but the ripple stay.

dont understand
should i order de ic5101 str-f5552?

[Longbow]

Re: hard repair from HR-DVS1EU smps

I can't read the screen too well, but it looks like almost 1 volt ripple on 12 volts supply? That is too much ripple in my opinion. Resistor 5105 OK? Is the ripple at the switching frequency, or at the power line frequency (100 Hz)? It might be time to order a new IC5101.

[rickou]

Re: hard repair from HR-DVS1EU smps

So I order a new ic5101 in the meanwhile I take one leg of the R5101 and take a external power supply and put 14.5V in the pin 4 of the IC and the PS is working fine.

So if the cap C5103 is 39uf in reality I have mesure 40uf.
For 39uF 25V what is the acceptable esr? I hope the problem lies in the IC...

[rickou]

Re: hard repair from HR-DVS1EU smps

I can't read the screen too well, but it looks like almost 1 volt ripple on 12 volts supply? That is too much ripple in my opinion. Resistor 5105 OK? Is the ripple at the switching frequency, or at the power line frequency (100 Hz)? It might be time to order a new IC5101.

I have 5V/Div ripple.

What is the ripple at the switching frequency or at the power line frequency?

[Longbow]

Re: hard repair from HR-DVS1EU smps

So I order a new ic5101 in the meanwhile I take one leg of the R5101 and take a external power supply and put 14.5V in the pin 4 of the IC and the PS is working fine.

Interesting experiment, but I would not use this method in the future! Is the voltage on pin 4 supposed to be 14.5v? You also have a diode D5103. I would replace the diode AND the capacitor. Ripple is too high. Also replace R5101. Good Luck.

[R_J]

Re: hard repair from HR-DVS1EU smps

1=17V <----positive voltage is ok
2=GND
3=-12V <-----negative voltage is low
4=GND
5=GND
6=12V <------- positive voltage is ok
7=GND
8=8V <------- + voltage not too bad
9=-11.4V <-------- negative voltage is low
10=8V <----------+ voltage not too bad
11=8V <----------+ voltage not too bad
12=4,9V <-------- + voltage not too bad
13=variable from 2V to 37V (Osciloscope10v/div 20.00uS) Way too low I bet C5207 4.7/100 is open
14=variable from 2V to 37V (Osciloscope10v/div 20.00uS)
15=0V <------- 15 & 16 connected together
16=0V
17=0V <-----17 & 18 connected together, Measure voltage between 15 & 17,bet its correct around 3.5volts
18=0V
19=2.3V <--- S. protect could be low,check CP5324 circuit protector
Scope the waveform on negative side of C5206 (18/50) and positive side of C5207 (4.7/100)I suspect you have a problem there somewhere

If the power supply was NOT working (meaning the primary) you would not have correct +17 and + 12 volts, They come from the same power supply.
If there was very high ripple on C5207 it could feed through R5317 and rase hell with the feed back of Q5301 and transfer that signal through the optocoupler

[eccerr0r]

Re: hard repair from HR-DVS1EU smps

I was kind of surprised C5207 was good according to post 7... I sort of don't believe that observation, so I'm out of ideas.

[Longbow]

Re: hard repair from HR-DVS1EU smps

RJ, I guess you've covered just about everything. Guess we can move on to another unit.

[rickou]

Re: hard repair from HR-DVS1EU smps

I just replace the ic5101 and now it works but I don't understand why. This IC was the last thing that I think that was the problem. I only replaced the IC and the ripple was gone. Can't understand how this is possible because the old IC worked fine if I use a external power supply like I said in post 11. How can a circuit make ripple?? Find time I had a problem like this. Thanks to all that have tried to help.

[R_J]

Re: hard repair from HR-DVS1EU smps

Good to here you have it repaired.
I have seen similar ic's that will not run at there frequency but will instead pulse on and off, this pulsing can be enough to give some of the voltages in the secondary especially if there is no current being drawn by them. I guess the +17 and +12 being switched off by the unit were not drawing much current so they showed there proper voltage at the power supply,the negatives voltages I suspect go to display which would be on drawing current so that would explain the low voltages there.
I'm suspect pin 3 of the ic was pulsing the primary and those pulses show up in the feedback winding, charging c5103 at that (much lower) frequency you saw on the scope.
and now that the ic's output is a clean sine wave at a much higher frequency,it charges the cap to the proper run voltage.

[Longbow]

Re: hard repair from HR-DVS1EU smps

I just replace the ic5101 and now it works but I don't understand why.

There is a big difference between powering the IC from a single diode/capacitor arrangement and powering it from a regulated d.c. supply. Once the current draw on that simple 1-diode supply becomes large enough, it can't maintain enough voltage on the filter capacitor so there would be more ripple and lower d.c. voltage. Who knows, maybe the internal FET was leaky, but not completely faulty? Maybe some other parts in the IC were drawing too much current. Sometimes resistance readings from Vcc to ground on the IC can give you these clues. Good fix, anyway.

[rickou]

Re: hard repair from HR-DVS1EU smps

Thanks to all.