Damage to the Supratech DVD player, model: Vision Helena

• Damage to the Supratech DVD player, model: Vision Helena
  Posted by macan on 26 Apr, 2017 14:15
• Hello friends of the forum:
  
  I have to repair, a DVD player, brand Supratech, and model: Vision Helena.
  
  The display does not turn on, and I found on the power supply, the fused input fuse and two 1N4007 diodes shorted.
  
  The switched-mode power supply has the HXY965 printed circuit board printed on the circuit board.
  
  After switching the fuse on the diodes and the 22microF 400V electrolytic capacitor (which I found dry), I have reconnected the DVD equipment, and a small explosion has occurred again, with fuse blowing.
  
  When looking at the printed circuit components with a magnifying glass, I have been able to see that the integrated control unit (KJV930) has a small crack in a corner, so it is very possible that it is damaged.
  
  I have been trying to get information from this CI (KJV930), and I have not got anything, could you help me?
  
  Greetings.

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• #1 Reply
  Posted by carl_lab on 27 Apr, 2017 08:47
• Do you know the output voltage of the power supply? Is it single or multiple voltage output?
  If single, why not replace the complete PS by an external 5$ wall outlet type power supply?
• #2 Reply
  Posted by macan on 27 Apr, 2017 09:03
• Hi Carl_lab, First of all thank you very much for your answer.
  As far as I can see, it has at least two output voltages, which I do not know.
  If someone could give me this information, or a schematic, it could help me find an alternative solution to the repair.
• #3 Reply
  Posted by CJay on 27 Apr, 2017 15:01
• it looks like a fairly generic power supply, the chip is probably similar to one of the Topswitch parts or similar but can you show us the rest of the inside of the DVD player and the solder side of the power supply please, that may make it obvious what the voltgaes need to be and give you more options
• #4 Reply
  Posted by bktemp on 27 Apr, 2017 20:49
• http://www.st.com/en/power-management/viper22a-e.html
• #5 Reply
  Posted by macan on 28 Apr, 2017 09:35
• Hi CJay, thank you very much for your response.
  
  As you tell me, I show a picture of the interior of the DVD, and the power supply, from various positions (including the printed circuit board).
  
  With the photo view of the printed circuit, I deduce that it has three output voltages.
  
  I also appreciate the response from bktemp, for the information you send me from C.I. VIPer22A. I have been able to see, which is the second reference that has the C.I., in addition to the KJV930.
  
  regards

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• #6 Reply
  Posted by CJay on 28 Apr, 2017 09:42
• OK, so three voltages, possibly 12V, 5V and 3.3V but at the moment we can't be sure.
  
  BKTemp has identified the chip type for you though, it's an ST part and they should be cheap enough to try one but before you do, test as many of the components on the PSU as you can, diodes, capacitors especially.
• #7 Reply
  Posted by carl_lab on 28 Apr, 2017 11:24
• Your PS has one regulated main output voltage and 2 unregulated outputs (one positive, one negative voltage).
  I would  measure primary winding resistance to find possible short.
  If no short, replace SMPS-IC and all mains rectifier diodes.
  
  Reconnect to mains over a 60W light bulb in series as a current limiter.
• #8 Reply
  Posted by samnmax on 28 Apr, 2017 14:15
• macan, have you checked the other PCB (the one with the CPU, USB etc.), it may have silkscreen markings for the three voltages. Otherwise the capacitor voltage ratings may give you a reasonable upper limit.
  
  I would assume the motors run at 12V like the ones on PC DVD readers, and that the decoder PCB runs at 5V since it has a USB port. The negative voltage may not even be used, I can't think of a reason why it would be used apart from a Vacuum Fluorescent Display. It uses LEDs for the display isn't it?
  
  If it's 12V and 5V it will be much easier to find a suitable replacement. 5V would be the big fat diode going out of the transformer and 12 the small one also pointing out. The negative voltage has the diode pointing towards the transformer.
• #9 Reply
  Posted by macan on 28 Apr, 2017 16:38
• Many thanks to all for your answers, which are helping me a lot to achieve the goal of repairing the power supply.
  
  I already ordered the C.I. VIPer22A to an Ebay supplier (they are very cheap components). Before changing it, I will check the remaining components, capacitors and diodes.
  
  And when I try, I will follow the advice of carl_lab, and I will put in the main power, a 60W lamp as current limiter.
  
  I have drawn a draft diagram (which I show), in which it can be seen that it has three output voltages. For the voltage value of the electrolytic capacitors, it appears that the voltages are + 12V, + 5V, and - ¿? (Negative), for the display, which appears to be of the fluorescent vacuum type. I have not seen any value of the tensions, in the serigraphy marks of the other PCBs
  
  Many thanks to all, and when I receive the IC, and do the test I will tell you the result.
  
  regards

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• #10 Reply
  Posted by carl_lab on 28 Apr, 2017 18:54
• Have you compared circuit around your IC and pinout of ST-IC (datasheet)?
  
  Pin 5-8 of ST-IC is interconnected together (DRAIN), pin 1+2 is interconnected together (SOURCE), just as your PCB photo shows, but I've not checked pin 3+4.
• #11 Reply
  Posted by macan on 29 Apr, 2017 11:15
• Hello carl_lab, pins 3 and 4 are not connected to each other, since pin 3 is FB, and 4 is VDD.
  Thank you very much for your help.
• #12 Reply
  Posted by carl_lab on 29 Apr, 2017 17:49
• Quote from: macan on 29 Apr, 2017 11:15

  ... pins 3 and 4 are not connected to each other...
  

  Yes, I know. I meant I've not checked if function of the 2 pins matches your PCB, or not.
• #13 Reply
  Posted by macan on 01 May, 2017 16:51
• Hi Carl_lab, I checked the connection of pins 3 and 4, of the CI (VIPer22A), and I was able to check that:
  The pin 3 goes to the output of the IC (opto coupler), and pin 4 goes to the positive of the input electrolytic capacitor (22microF, 400V), so I think it is correct.
• #14 Reply
  Posted by carl_lab on 01 May, 2017 20:35
• OK, then good luck for your repair.   
• #15 Reply
  Posted by macan on 10 May, 2017 20:58
• Hello fellow forum.
  I already received the IC (VIPer22A), and I replaced it.
  I checked the four diodes of the bridge rectifier, and to test introduced in series with the input of the power supply, a 60W lamp.
  The result was that I did not get any response, the lamp remained off.
  So I decided to remove this protection and connect directly (without the limitation of the lamp). The result was that now it does not blow the fuse and I have direct voltage (311 Vdc), but there is no output, because it does not oscillate the circuit.
  I have measured that the voltage at pin 4 of the IC (VDD), is not good, since it is 2.2 Vdc.
  I checked the capacitor capacitance (CP12) of the voltage VDD, and it is correct, I have checked the diodes DP5 and DP8 and they are fine.
  
  What do you suggest?
  
  I have removed the schematic of the power supply, and I hope it has no errors.

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• #16 Reply
  Posted by macan on 22 Jun, 2017 09:35
• Please, can anyone help me? I still have not solved the problem.
  Thank you
• #17 Reply
  Posted by amyk on 22 Jun, 2017 11:25
• That looks like it should be +12, -12, and +5, going by the capacitor values and reference divider.
  
  You can try powering it from a PC AT power supply to make sure the rest of it works, before spending more effort on fixing the PSU.
  
  I would check and replace all the electrolytic capacitors. They may have become high-ESR.
• #18 Reply
  Posted by CJay on 22 Jun, 2017 11:40
• Load the power supply with resistors and see if it works, you may have already fixed it and have a different fault on the rest of the player.
• #19 Reply
  Posted by PA0PBZ on 22 Jun, 2017 12:56
• Do you have the 300V DC on the drain?
• #20 Reply
  Posted by Armadillo on 22 Jun, 2017 17:02
• AC input UNPLUGGED.
  
  Please measure Resistance Ohm, Pin 1 of transformer to Pin 8 of viper22.
• #21 Reply
  Posted by macan on 22 Jun, 2017 17:19
• Thank you all for your answers.
  The truth is that it is a pleasure to be able to receive help, from anywhere in the world (Internet wonders)
  Hi amyk, I'm not sure that those values ??are the tensions. I do not have ESR tester, but if I have capacity tester, only. However you are right, I will follow your advice to change all the capacitors.
  
  Hi CJay, I thought the problem was only in the power supply, but you're right, I'll replace the electrolytic capacitors, and I'll charge the output with some resistors.
  
  Hi PAOPBZ, If on pins 8,7,6, and 5 (Drain) of the IC, I have the 300 V dc, but when I look at them, I see that the reading of the meter does not stay fixed.
  
  Hello Armadillo, the voltage (measured with a digital voltmeter) on pin 3 of the IC, is fluctuating. When I measure it with an anaerogical meter it fluctuates between zero and 100 mV dc (fluctuation frequency is about 0.5 Hz / s)
  I measured the voltage on pin 4 (Vdd) with an analog voltmeter, and I observed that it fluctuates between 7 and 12 Vdc, with an approximate frequency of 0.5 Hz / s
  
  Greetings to all
• #22 Reply
  Posted by PA0PBZ on 22 Jun, 2017 18:16
• Quote from: macan on 22 Jun, 2017 17:19

  I measured the voltage on pin 4 (Vdd) with an analog voltmeter, and I observed that it fluctuates between 7 and 12 Vdc, with an approximate frequency of 0.5 Hz / s
  

  
  So the thing tries to start and fails. Did you check the diodes on the secondary side?
  
• #23 Reply
  Posted by Armadillo on 23 Jun, 2017 06:44
• I suspect shorted turns, since VDD cannot rise up pass 14.5Volts.
  Do you have a ringer or a DSO?